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Last Post 16 Aug 2016 03:26 PM by Fair
Vorshlag Ford Focus RS Development Thread
|11 Aug 2016 02:59 PM
Project Kickoff - July 8, 2016:
The 2016 Ford Focus RS, AWD turbo compact, has hit the streets - and we just got our hands on one for the next 10 days. During that time we plan on measuring, weighing, and testing the OEM bits - and hopefully developing some new items for this chassis.
The new Ford Focus RS is being introduced in the USA in July 2016 as a 2016 model. The key features are: All Wheel Drive, 2.3L 350 hp turbocharged 4 cylinder engine, compact size, big Brembo brakes, and a $36,755 starting price. These cars are just starting to hit the dealerships across the country this week (many with large mark-ups) and our friend Todd Earsley at MyShopAssist
just got his the day before he left town to go race his Mitsubishi EVO at an Optima event in Colorado.
- our little forum which gets a surprising amount of traffic
- a Forum for S197 and S550 Mustang track owners (which we sponsor)
- a Forum for S197 and S550 Mustang track owners (which we sponsor)
- a forum for SCCA racers who autocross, road race, and more (which we sponsor)
Above are the forums where this thread will be updated, questions answered, etc. We didn't want to push this thread where it wasn't wanted, so we're sticking with forums we own or sponsor only.
WHY SHOULD WE CARE?
Why is this Focus RS car important? For one it fills a niche now that the AWD turbo Mitsubishi EVO is no longer being made. That departure last year left a huge hole in the AWD turbo compact market.
We had fun with the 3610 pound EVO X MR back in 2008-09. We used that to developed a number of suspension products (shocks, camber plates, shock mounts) as well as figured out better solutions for the wheels, exhaust, and even came up with some cooling fixes for the DSG's sequential gearbox. We had a lot of fun racing it in NASA Time Trials and SCCA autocross semi-effectively (it won some TTA events and did well in BSP autocross class locally).
The rest of the AWD turbo market is fairly underwhelming. After the remarkably light and fast GR model Subaru STi left us (shown above) it became a bigger/heavier car that went up in price. The 2017 model STi is now 3400 pounds and starts at $35,000, but they go way up from there (the popular Limited trim level STI is $40,000). The Subarus are also just... odd. The flat 4 engine they use is hung way out in front and full of bad ideas, which makes Subarus a "love it or hate it" kind of car. And they don't do as well in autocross or on track as the EVOs of the same years, so losing the EVO was a significant loss - that Ford is trying to fill.
The only other AWD turbo compact we have in the USA is the Golf R, which itself has become a heavy compact car with an even smaller following. The 2016 Golf R with the DSG trans is close to 3400 pounds and $39,000. We worked with a tester on the new Mark VII VW platform, shown above, to create a camber/caster plate for this new chassis earlier this year. His car was a 2015 GTI - these are FWD (the AWD model is much more costly) but had the slick DSG dual sequential gearbox - like the EVO X MR had. The GTI is nearly 300 pounds lighter than the new Focus, as you will see below, but the Golf R (292 hp) is almost the same - but with a better gearbox.
So, Ford has added its hat to the "AWD turbo compact car" ring in the USA. And looking at it's current competitors, it is neither overpriced nor overweight. But does it offers more than these other cars? The $36,775 base price might also be a bit misleading - it is easy to option these cars to $45,000, and some dealers are marking them up $10K beyond that (which goes away fairly quickly, once initial demand catches up with supply).
LET'S FOCUS HERE...
We here at Vorshlag try to get our hands on the "hot new cars" that people might want to use on a road course or autocross, and we use our Vorshlag Test Pilot Program to reach out to folks with these cars when they first hit the streets. If we can borrow their car for a week or two it allows us to get real corner weights of the cars (because OEM "curb weights" are usually junk data), measure for larger wheels, measure brake pads to help develop track worthy options, look for any exhaust system issues, and of course measure suspension bits.
I got a message two days ago that basically said: "If you want to develop stuff for my RS while I am out of town for the next ten days, come get it!"
So yesterday my engineer Jason and I went to the Evolution Dynamics
/ MSA shop space and picked this beauty up. Jason drove it back the ~25 miles to our shop (nearly doubling the mileage on the odometer) and had these things to say:
"Lots of power off the line, surprisingly good acceleration. Ride quality is harsh, the steering is very fast, it is *very darty and wants to tramline badly. The shifter needs some help."
- Jason @ Vorshlag
* We have since measured the alignment and this car came with 1/8" of total front toe out, which might explain the dartiness.
After shop manager Brad shot a few outside pictures we brought it inside and checked the initial ride height at all 4 corners, camber and toe front and rear, then put it up on the lift and slid our digital corner weight scales underneath to get a weight. As always I took a guess - without knowing anything about this car other than what I could see - and I guessed 3220 pounds. I'm usually pretty close on my weight guesses but this time I was off by over 200 pounds. This car had a FULL tank of fuel, which could explain some of the higher weight...
Wow, 3445 pounds full of fuel is a lot for a car considered a compact - but again, look at its competitors and they are all in this range. AWD definitely adds some weight to the FWD Focus ST, as do the giant Brembo calipers and 19x8" wheels Ford decided to put on this car. That would be the first thing I changed, by the way - the OEM wheels. The 235/35/19 rubber looks too narrow on this car and the sidewalls are too short, which might explain the ride harshness. We are pulling the wheels and tires + brakes off to weigh them now...
Ford used the old "scoop and flap" method of front brake cooling, just like on the 2015 Mustang and on Porsches since the 1980s. This is where a brake duct or in this case a low pressure inducing tunnel under the front end puts air near the inside front suspension, then a flap on the control arm diverts this flow towards the brakes. It doesn't work all that well, but its something.
With the weight this car has I suspect a dedicated brake cooling system will be beneficial for track use, so we will look into that for this Focus.
There are dozens more pictures we have taken and need to analyze. There are definitely things that can be improved in the exhaust, the wheels, and suspension.
I haven't even driven the focus yet, so I will go drive it around the block a few times and get a feel for it. We are looking at the suspension and brakes very closely right now and will report back in the next few days, to see if we can improve on what Ford has built...
Terry Fair - www.vorshlag.com
|11 Aug 2016 03:10 PM
Update for August 10th, 2016:
It has been a a little over a month since our first post and the Focus RS has been put through its paces at a local race track by Vorshlag (MSR-Cresson), then it was raced at two different Optima/USCA 2 day competition weekends by the owner Todd (Charlotte and COTA). We have gained a lot of first-hand experience with this car and several issues jumped out at us, which we will share in this post. We will also offer up a few potential solutions to these issues.
When reading this, please understand that we are not auto journalists, looking to gain readership with a shiny happy car review and a few funny quips. There won't be a cup holder count, radio features won't be explained, none of that. We care about simpler things than car mag writers - we want to know how does a car go, stop, and turn in track and/or autocross use. Also, is it reliable on track, or does it overheat some system quickly? Are there any electronic gremlins that deter from the track experience, things like that. Honestly we're a bit jaded and have seen so many whiz-bang special new hotness cars that when finally tested on track, were a flop. And we've seen others that did all right. This RS seems in the middle of that range, so far.
While the RS is popular with the auto journalist types, it is also a hugely
popular car on the internets. The Focus forum fanboys are extremely unforgiving of anyone saying anything critical about this car. There is a lot of special sounding jargon and internet mythology being associated with the Focus RS, but frankly I just don't buy into the hocus pocus.
This RS is just a car. It is a small-ish car with AWD (sometimes), decent (front) brakes, and a turbocharged 350 hp engine. It weighs a good bit, has a relatively small tire, and a bunch of it's weight is on the nose (59% front weight biased). Just so we are all on the same page, these are called: the facts.
There is no magic breakthrough technology on this car (except the RDU - see documents below - but it doesn't work well on track). Sure, the RS has adjustable shocks (cockpit adjustable twin tubes, circa 1990), a launch control "rev limiter" mode (which has been on many cars for years, and with as complex of a procedure this car has to set it, this has very limited usefulness), and there is active disengagement of the rear drive axle - which is not usually a good thing. Bill Caswell mentioned this "Torque Vectoring Rear Drive Module (RDM), which combines a differential and two hydraulically activated clutches to control the power distribution to the rear wheels"
in this R&T article
. He did some track driving in an RS which put the rear diff (admittedly very small) into thermal overload, which disengages the rear drive completely. Many others are seeing this same issue, including me at our test and the owner Todd when he drove it at Optima events.
In my track test in-car video (see below) I mention many times while driving the car on track that the car felt like it had no rear drive at all. "It just handles like a Front Wheel Drive car", and that was because the rear drive unit was disengaged almost the entire time I was on track. This isn't me being hyper critical, its a known flaw in the RS. I've driven many AWD cars (Subarus, EVOs, etc) on track in the past 15 years and never had this issue happen on another car, until the Focus RS. It was disappointing to say the least, and "rumor has it" that Ford is coming out with a diff cooler retrofit unit that you might want to add to your race prep budget if you plan on tracking your Focus RS.
In this post we also disassemble this car's suspension and brakes, to weigh and measure things. Again, to show the facts. Many items look correctly sized for the power this car has (front brakes), while others look woefully undersized (rear axle, driveshaft, halfshafts, rear brakes, wheel width, tire width, etc). Some of these judgement calls are indeed guesstimates made by our crew, which includes engineers, race car fabricators, and other race experienced folks. Take that as you will, but its all part of our honest assessment of this chassis after tearing it apart and racing it on track first hand.
We are not Focus forum experts, nor blind believer internet fan boys, and we don't have all of the answers (or special lingo) for the issues we noted on track. All we know and trust about this car are what we can see, measure, and test first hand. When driven on track at three different venues by two different drivers, this car's oil temps got very hot very quickly, as did the coolant temps. The rear drive unit seemed be disengaged constantly; if you ever overlap the gas and brake (which happens when you Left Foot Brake - which all experienced racers should be doing if they don't need to downshift in a corner) or if the rear diff fluid gets hot (which it does).
There are many things we feel are needed to make this car more reliable on track, and to catch up with similar AWD turbo 4 doors from the past 10 years. Sure, it might be on par with a current VW Golf R, but not a Mitsubishi EVO X or GR Subaru STi (which had similar prices when new). An engine oil cooler is a must do upgrade on the RS for track use, unless you drive like Mr Magoo or race above the Arctic Circle. The 235mm Michelin PSS tires are overwhelmed by the power level and WEIGHT that this car has on track. The lack of camber adjustment up front shreds the outer shoulders of the front tires, which are doing almost all of the work on this car. The stock dampers and springs - although adjustable - are still too soft for this car's weight and power, so you get a lot of roll/heave/dive even with not-soft 300 treadwear tires. Vorshlag has a set of monotube coilovers on hand to install on this car, plus we are designing the camber plates for use with those, to be installed in the coming weeks before another Optima event.
Ford isn't in the business of making and selling 100% indestructible track terrors - they never have been - and this one is no different. It needs help to deal with the higher thermal load of a turbocharged engine, and cool the undersized driveline components. So while we may seem critical of this car in this post, know that we are pointing out the flaws we see - like we do on all cars we dig into this far. We're also committed to fixing or minimizing those issues with more track-worthy components, as time and budget allows. We end up needing to do this for almost every new car we encounter.
FOCUS RS DECONSTRUCTION
After the brief "intro" post on July 8th we had a chance to really dig into this Focus - by taking it apart and measuring lots of things. Our intent was to see what this car was capable of, and checking the potential for a camber plate design that utilized the OEM springs and struts. We also wanted to measure to see potential for wheel and tire width increases, brake cooling, engine cooling, etc. There were several eye opening discoveries which we have detailed in the pictures below.
After getting the car in the air we started by looking at many things underneath, under the hood, and then dug further. Let's start under the car.
The RS front undertray is a hodge-podge of scoops and shapes...
This unusually shaped, extremely non-flat fabric/plastic front undertray has several NACA scoops to help direct air to hot things underhood. This would be a decent design if this fabric panel wasn't so flimsy and non-flat. We will look at a smooth bottom aluminum undertray (and short splitter) with the NACA ducts added as needed.
The diameter of the driveshaft that feeds power to the rear differential, or as the fanboys call it the "Rear Drive Unit" (RDU), is remarkably small. The section above right necks down to the size of my finger. How does this transmit "up to 70% power" of 350 hp to the rear wheels? Doesn't add up.
Not to mention the Rear differential itself, which is painfully small in the RS. This is the size of what you'd expect to see in a side-by-side or ATV that has a 500-750cc engine. Not exaggerating here; this differential housing is small. I've never seen a car with any sort of rear drive that used an axle this small in 3 decades. It is no wonder it overheats and disengages the rear drive, to protect this differential from damage.
Some light reading from Ford documents that explains the complicated controls and overtemp protection on the RDU
After some digging through Ford documents, turns out this car doesn't even have a differential unit at all. There are electronically controlled clutches in the center diff as well as one for each rear drive axle. There are a network of computers, hydraulics, and robots controlling torque to each wheel. Lots of fancy doo-dads that are neat on paper, but terrible in practice. Hopefully there are some industrious folks who can crack the code and reprogram this unit to work better for performance driving.
This images above show the rear axle housing and rear suspension from a 2008 EVO X, which we spent two years tracking and autocrossing with. The differential housing looks like a similar shape but is substantially larger in person, and the rear suspension has aluminum multi-link arms. Just wanted to show what was available 8 years ago in AWD 4 doors.
The Focus RS exhaust system is oddly shaped around one of the center bearings of the THREE PIECE rear driveshaft. Yes, this subcompact car with a 104" wheelbase, has a 3-piece rear driveshaft. Which is a bit nutty given the length, but that seems to be a theme in this car. The exhaust is smashed nearly flat there, but there is ample room to leave it full size there. The aftermarket can and will fix this.
Sure enough, Magnaflow has already responded with a better exhaust routing, shown above. No smashed section, no problem. Ford does this exhaust smash trick on a number of their cars, and it is mind boggling.
The rest of the factory RS exhaust isn't too bad, just a bit on a small side for a 350 hp turbo car. There is a bit of a gimmick feature out back - a computer controlled exhaust bypass valve which can bypass the muffler. Hey, even the Corvette Z06 has this. But it seems that some RS tuners are using this and some "tuning tricks" to make the exhaust "pop" and burble. To me this is akin to adding an exhaust whistle
... If I see a tuner bragging about how they add this "feature", I will label them as a clown. #BubRub #WooWoo
One of the worst features of the rear suspension is this trailing arm torsion blade. This is a 1960s-era design used on the VW bug, where you use a flat spring steel arm that can accommodate the suspension arc by twisting. This arm is needed to locate the suspension fore-aft during travel. Massive rubber bushing up front also allows for all of this twist. That front bushing should get a spherical. You only do this type of rear suspension to save money.
The rest of the rear suspension is heavy, stamped steel bits. Not an ounce of aluminum anywhere back here. This seems to have been done for cost savings. I would expect more from a nearly $38K car, but I guess I'm picky. At least they improved on the janky rear swaybar endlink design used on the Focus ST, but that is about it.
This Focus is made by the same company that designed and built the S550 Mustang (shown above), which has an independent rear suspension light years ahead of the Focus - and which can take real power to a properly sized rear differential. Aluminum is used on the throughout Mustang's rear suspension to save weight. And while some of the GT350 Mustangs (non-track pack cars) are seeing differential overtemp issues on track, it seems to be a programming glitch. This only affect the small portion of these Mustangs that even have
a temp sensor in the rear differential housing. We've seen S550 Mustangs being abused on track for years with no long term negative effects.
Engine bay in the RS is the definition of "tight". There's not a whole lot of space for a turbocharged 2.3-liter four-cylinder and transaxle that sends 350 hp and 350 lb-ft of torque to all four wheels. The bulk of the drivetrain is in front of the front axle centerline, which explains the 59% front weight bias. The Subarus and EVOs suffer from the same thing - they all tend to sit around 58% or 59% front bias.
Ford does the RS no favors by putting a full sized battery in the cramped driver's side corner of the engine bay, either. I'm sure they had their reasons, but this would be something I moved to the trunk area on even a semi-serious build.
The best part of this car, to me, are the front brakes. The calipers up front are an OEM style Brembo 4 piston matched with beefy rotors. Lots of brake capability for a Subcompact car, and I we will talk about their track worthiness below. The front brakes are one of the few things on the RS that are matched well with the 3450 pound tested weight.
Now the calipers and rotors aren't anything magical - no co-cast aluminum brake hats or radial mount calipers - just a properly sized, OEM style 4-piston Brembo solution and decently sized iron rotor. Not gigantically silly or undersized, but just right. The front rotor weights and measurements are shown above. They are also not big enough to justify a 19" wheel - we could fit 17" wheels over these front brakes. Ford's 19" wheel choice was simply a fashion statement.
|11 Aug 2016 03:11 PM
continued from above
There is also an OEM front brake cooling solution on the RS, shown above and below. In the image above you can see the smooth plastic duct that takes air from a front scoop/opening and points it into the front fender liner.
Here you can see the fender liner exhaust for the brake cooling air (at left), and from here the higher pressure cooling air stream is thrown at a flap on the control arm. This flap, in theory, guides the air towards the inside of the rotor. We call this a "scoop and flap" brake cooling solution. No, its not as effective as a properly hosed/ducted brake cooling system like you see us build for race cars, but its better than nothing. I think it was Porsche who came up with this scoop and flap technique on factory 911s back in the 1980s? Ford has done something similar on some of the S550 Mustangs also.
The rear brakes seem disproportionately small, and originally I suspected they were the same units fitted to the "rental car fleet" Focus, but I was wrong. When we sent the brake pad scans to our friends at G-LOC Brakes they assured us these were new pad shapes, so the small diameter, non-vented rotor and single piston sliding caliper might be unique to the RS. It is not impressive in size or style - but it should be cheap to replace when parts wear.
Here we see the weights on the somewhat heavy 19" x 8" factory wheels and 235/35/19 Michelin Pilot Super Sport (PSS) tires. There is supposedly another optional tire for these cars, but this RS was ordered with the base standard set knowing they would be quickly replaced. This 235 Michelin PSS shows to be 23 pounds on the TireRack website
, so that means this 19x8" wheel should weigh about 28.5 pounds (amazingly heavy) if you do the math. There are definitely some pounds to drop going to a wider 17" or 18" aftermarket wheel - and we plan to measure for new rims after the coilovers and camber plates are installed. We will talk more about that in a future post.
These are pictures of the front strut tower and strut/spring assembly. There is nowhere for the strut with the large diameter OEM spring to go - no room inboard - so there will be no OEM spring style camber plates. I explain this in more detail in the video below, "Suspension Challenges".
Just getting to the top of the strut towers involved removing about 19 layers of stuff under the hood. This is one of the most restrictive engine brace / cover systems we have ever seen.
The wiring for the adjustable twin tube shocks has a connector above the strut tower brace, shown above left. The wiring passes through the top of the brace as shown above right.
After 90 minutes of careful removal, we could finally see
the tops of the strut towers and the strut top mounts. The factory RS engine and strut tower brace is crucial and must be retained. It is 7.5 pounds of stamped / welded / fabricated steel. This elaborate brace ties into a number of items, like the strut towers, wiper motors, and lots of plastic covers (aka: Tupperware) that hide the back of the engine bay and strut towers. The OEM strut mount is unusual in that it is bolted into the tower via bolts from above. This is backwards from nearly every McPherson strut car we have ever seen, which usually have studs that protrude through the the tower from below.
After you can access the top of the towers, actually removing the front strut assemblies takes more time. Support the bottom of the control arm, remove the front swaybar end link, disconnect several wiring connectors, then unbolt the strut to spindle clamping bolt. Spread the split in the spindle clamp as shown (above right) with a short extension square drive end. Then pull the lower control arm down. Now you should be able to pull the bottom of the strut out of the top of the spindle clamp. Once that is uncorked, you can unbolt the three bolts at the top of strut mount, freeing it from the engine bay.
This unusual, raised reinforcement lip on the underside of the strut tower (above left) is another thing preventing a camber plate that could work with the OEM springs. Making a spacer to sit below that lip (so the plate could slide inboard) would eat up too much much stack-up height, so it would be nearly impossible to keep an adjustable top mount from raising the front ride height. Switching to an adjustable height coilover strut makes all of this moot - the smaller diameter springs allow inboard travel, and the adjustable spring perch height counter acts the slightly higher stack-up height needed to clear the raised lip under the strut tower. The OEM strut + spring + top mount weights nearly 17 pounds, as shown above right. Coilovers always seem to weigh less, which is a bonus.
After we finally had the strut off the car and the spring compressed, we were ready to remove the strut top mount. We wanted to remove the coil spring so we could digitally rate it, but we stopped short. Why? The wiring for the adjustable shocks could have been ripped when removing the top mount. Yea yea yea, "it looks so easy". Trust us, it wasn't.
To remove the strut top nut would require an impact to spin the nut loose. Even if we custom made a "windowed" socket to allow the wire to pass through, we would have still probably ripped the wiring, ruining the OEM struts. With the chances of making an OEM spring compatible camber plate at zero, we cut our losses and decided no not rate the springs until we had replacement struts. The space constraints made it obvious we had to move to a coilover anyway. This also means there is not an easy path to installing lowering springs (which almost never have enough spring rate anyway).
We had the rear shocks off but neglected to get a picture of these. Will make a point to weigh and photograph these when we install the coilovers next week.
This is a quick video we made over a couple of days as we disassembled the Focus suspension, looking for a way to make a camber plate, improve spring rates, measure for better dampers, etc.
YouTube video: https://youtu.be/DIzkQCFfF94
We are trying to point out the problems we see and offer up possible solutions. There are some good and bad things we noted here, but no super trick zero money solutions for improving handling performance. This video has a few thousand views already and lots of thumbs down. Blame the messenger, I guess?
PART TIME AWD SYSTEM
This internal Ford document about the Focus RS AWD system explains a lot. "During normal operation, most of the torque is delivered to the front wheels."
is exactly how it felt to me all the time.
Read this and see what you think. Sounds pretty funky.
TRACK TEST at MSR-CRESSON 1.7 CCW, JULY 15, 2016
Brad and I trailered the Focus out to Motorsport Ranch on Friday morning July 15th, leaving my house at 5:30 am. We arrived at the track at 6:30 am, just after sun up, and started to unload. This was the first time in a long while where we got to run on a "member day" at MSR. There were close to 15-20 cars on track with me during the first 2 sessions of that morning, so there was a bit of traffic to deal with - but this also gave us a good gauge of how well the car was doing. Weather was mild but threatening rain, so we wanted to get a couple of sessions in and head out before we got soaked.
We mounted two video cameras, a microphone (still testing optimum placement - these videos still had too much wind noise), and one of our trusty AiM SOLO predictive lap timer/data loggers. I have used this exact AiM unit dozens of times at this track and it always reads within .1 seconds of the AMB transponder timing loop on a NASA race weekend. It isn't some free phone timing app with a slow GPS transponder - this has 3 accelerometers and a 10 Hz GPS. Sidebar - one of my friends used my other AiM and ran his cheesy phone timer app at this same event, and the phone "lap timer" was consistently 4 seconds a lap off!
Event Photo Gallery
Temps here in North Texas in late July can be oppressively hot, but we got lucky. With the first session on track starting at 7:30 am, ambient temps were only 79°F and overcast, so we were encouraged. We had high hopes for the RS and anticipated some good lap times. These are temps we normally don't see until Spring or Fall.
Below is the course map for the 1.7 mile MSR course, which we made for the use of our NASA Texas Time Trial group, (I do this for every NASA Texas event we attend, and hand them out at the driver's meeting). This is the most common
course and direction for Motorsport Ranch's 3 different track configurations. It is also the one I am most familiar with, and it is the easiest to drive.
This course is relatively flat, easy to learn, and has no dangerous "off" sections to worry about. The only thing we caution drivers about on the MSR 1.7 is to avoid the high curbing in a few areas - namely in "Rattle Snake", which are a series of esses in T10 and T11. I've seen people high center their car or worse when getting greedy in that section, so I tell my students to only touch the paint, and always stay off the big curbs.
Just so you know a little about my experience in general and at this track, I wanted to preface this post with a little background. I did my first track event in 1988 and have been driving on track, competing at road course events, and instructing for HPDE students for nearly 3 decades. I hold a NASA Time Trial competition license and have raced in several wheel to wheel road races as well. At heart I'm an autocrosser (since 1987), and I use the aggressive car control I learned dodging cones on track to maximize driving on the "Friction Circle". Watch the data logged g-load trace in the video below: a good "friction circle" driver can make the trace follow a circle when transitioning from lateral cornering to braking and into acceleration. I'm by no means perfect, but I try to always keep the tires loaded up to the extent of their limits - you can hear the tires "singing" in every hot lap.
I am also fairly tough on brakes, but I hate coasting. Coasting is death!
I am either on the gas or on the brakes at all times, and I Left Foot Brake (when no downshift is needed) so there is no time coasting while moving my feet around. In a manual transmission car I always rev match downshift using the heel-toe method, and do not abuse engines by downshifting early and relying on engine braking. Brake pad replacements are much cheaper than engine rebuilds.
I also try to data log and shoot video of nearly every lap I drive on track or autocross, in the pursuit of both maximizing the car and my own driving. I am no "pro driver" by any means, and acknowledge that there are always someone faster, but I'd say... I'm no slouch. Owning Vorshlag and being at track events constantly for the past 28 years has allowed me to drive upwards of 1000 different cars, and likely 150+ different cars on track.
At MSR-Cresson's CCW 1.7 mile layout I have driven maybe 300-400 laps, and have also run their 1.3 mile CCW track, the 3.1 mile CCW track, and the CW 1.7 mile circuit here many times over the past 10 years. I have set 4 or 5 NASA class track records at this track in various classes and cars.
Reference times: My quickest lap time in a street legal car on the MSR 1.7 CCW course is a 1:17.25
, which was set in 2014 in our NASA TT3 classed 2011 Mustang GT. My most recent NASA lap times back in March of 2016 were in my TTC classed 1992 Corvette (nearly bone stock in every way) with a 1:21.9
and a 1:27.6
in our TTD classed BMW E46 330. All of those times were on Hoosier DOT legal R-compound tires. The TTD lap time was a bit disappointing, though, because we still had the bone stock drivetrain (195 whp) and I made my best lap times on heavily corded 245mm Hoosier R7 DOT tires. That 1:27 lap was painfully slow but still good enough for the win.
To keep from damaging a brand new car with 83 miles on it, I decided to stay off all of the high FIA curbs
on the apexes of nearly every turn here. To be consistent and sage, I would instead just "kiss the paint" on the apex curbing, to use all of the paved track available. The exit curbing is all standard FIA semi-flat "gator teeth" concrete curbing, which is safe to drive on, which I DID use to maximize corner exit room. I kept engine revs under 6000 RPMs, but vowed to push the car as hard as I could while keeping off the dirt. I didn't want to be accused of "sandbagging" the baseline track times, so that when we do changes there could be a huge improvement.
I ran the car in "Street" mode in the first session and "Track" mode in the second session. "Drift" mode did not seem appropriate for getting fast lap times. In both sessions the Traction / Stability control system was turned off completely.... press and hold the button for 5 seconds, while a counter dials down, then it says the system is off. It wouldn't stay off, but I will get to that.
|11 Aug 2016 03:11 PM
continued from above
The 8 laps in the 7:30 am session on track were spent learning the car, navigating through traffic, listening to the front tires howl, and seeing the oil temps climb and climb. I came in after only 8 laps due to increasingly high oil temperatures (285°F was all I was willing to see in this brand new engine). Again, it was only 79°F ambient and I wasn't over-revving or drifting or anything unusual - I was pushing the car as hard as I would any other, not abusively. This first set of 8 laps were somewhat boring and I had a best of a 1:28.5, which is admittedly slow.
As you can see in the image above, the Focus suffered from a lot of body roll. It also was losing camber badly on the front wheels - the loaded front wheel in the picture above has probably 2 degrees positive
camber, which is never good. With that positive camber shown in the image above it is no wonder that the outside half of the front tires were showing serious wear in only 8 laps on this super smooth, low tire degradation track surface.
Here is a picture of the car braking into T9, after the fastest straight on this course. As you can see, there was also a lot of brake dive. The springs appeared to be too soft to deal with even the moderate grip levels of the Michelin PSS. The brakes did feel pretty damned good - which was about the only thing I didn't complain about all day. With stock pads and fluid I wasn't able to ever boil fluid/lose pedal or fade the pads. If the grip level of the tires is upgraded we might have to re-assess the brake fluid and pad compound.
The tire and boost pressures would have been better at 500psi!
After these 8 laps (with 3 cool downs in there, so 5 hot laps) I came into the pits and Brad quickly used an IR gun to get a few temps... intercooler, brake rotors, radiator, etc. Nothing seemed extraordinary. The tires had crept up from 30 psi cold to 40 psi hot, which was about what we expected. We bled them down to 38 psi hot and kept them there for the next session, which was about an hour later.
Luckily the weather was overcast and the ambient temps stayed at 79°F, which was remarkably cool for a mid July day in Texas (normally it would be in the 90F+ range by now). With not much sun yet the track temp was only around 100°F, which would keep the tires from overheating.
We parked the RS with the hood up facing into a small breeze to help cool off the engine and coolers for the 65-70 minutes we waited while the open wheel cars (30 minutes), motorcycles (30 minutes) had their first sessions. The track requires all member day drivers to be in a full fire suit, and the super high humidity (nearing 100%) meant that you will sweat a lot. The first thing we did after cooling off the car was shed our suits and drink plenty of water.
I gridded the RS closer to the front of the pack that went out in session two to try to avoid the slower Spec Miatas and a few other street cars that were poking around. I got out on track and pointed the race cars by quickly.
We had re-checked tire pressures to get them back to 40psi when hot, and this time set the car in "Track" mode. It was a bit crowded again but not so much that I couldn't get 3 hot laps without traffic, shown in the video below.
With as bad as the skies and forecast looked I was pushing to make this my fastest and last session of the day. It would either start to rain or just get so much hotter it wouldn't matter. Somehow it rained everywhere else in the metroplex but never did in Cresson.
The issue was the oil temps crept up rather quickly, and after 3 laps I had to alternate cool down laps with hot laps. After one cool down lap the oil temps would drop below 300F and I could make one more hot lap, then the oil was near 300F again. On the first lap the PSS tires have virtually no grip (when cold) but by lap 2 they were up to temp. The tires got hotter every lap and were starting to overheat and lose grip after about 5 or 6 laps.
In-car video from 3 laps in the 2nd session is here.
This overheating of oil and tires worked against me - I never got a clear lap of traffic in either session when both the tires and oil temps were both in their optimal zone. The predictive lap timer showed a possible "1:26.6" time on lap 5, but I caught a train of 6 cars going into the last turn (Big Bend) and had to back off considerably that time. The best lap I could put together was a 1:27.40 on lap 7, but I nearly matched that time with a 1:27.50 on lap 3 in this same session. Again - there was a little more in it, but I would have needed a completely clear track and a perfect drive when everything was up to temp.
Catching and passing this GT4 was fun, but he reeled me back in and repassed the Focus later
Most of the cars on track with me that day were dedicated race cars, so the Focus was at a pretty big disadvantage with the 300 treadwear 235mm tires. Even the Toyo equipped Spec Miatas were leaving the Focus in the corners. I did play around with a Porsche GT4 a little, but after passing this car he caught back up and repassed me later.
The RS' 1:27 lap time nearly matched my times in a BMW E46 330 with 195 whp running at 3285 pounds back in March (with similar conditions). The BMW was indeed a bit lighter (3285 lbs in the BMW vs 3650 lbs in the RS, with driver), and much easier to drive at the limit. Both cars had equally excellent brakes, but the BMW had roughly 150 less hp. The 245mm tires on the BMW were a hair bigger and better compound, but were 8 weekends old, the compound was dead and the tread was badly corded.
RS Track Driving Impressions
At the end of the second session the car was running hot and the tires were pretty shredded (see the end of my in-car video for what they looked like after 16 laps). Brad and I loaded up the Focus and headed back to the shop.
Obviously if you watched my in-car video above you heard me complaining about understeer. Massive amounts of steady state understeer was all this car could produce. I suspect that the "RDU" system shut down almost immediately and I was essentially driving a Front Wheel Drive car for all 16 laps. Again, was it the fact that I used LFB technique on a handful of corners? Was it an overheated RDU? Who knows.
I also noted that the stability control was fighting me like it was still on, yet it was clearly turned off before both sessions. Something in my driving style pissed off the little computers and kept trying to keep the rear from ever stepping out. I would have loved to see a bit more turn-in, but it was not possible. Yes, it was in "Track" mode, too. All it would do was plow... the more throttle I gave it mid-corner, the more understeer it produced. There was no trick I didn't try - nothing worked. It felt like a FWD car the entire time.
Power delivery was rather lackluster, and some have speculated that the odometer reading (83 miles) was something that the computer didn't like and kept it from making full boost. This is nothing I could control that day. Now the car has several thousand miles on the clock, and a COBB Accessport and Sage 1 custom tune was added, and makes 330 whp. This is how Todd raced it at COTA last weekend.
So yea, it needs a lot of handling help, more tire, and lots of cooling upgrades. We're on it!
If you have read my race write-ups before you might remember that these Optima/USCA are events lots of fun. They break cars into 4 classes, require 200 or higher treadwear tires, some street going equipment is mandated, each car runs in 3 competition driving events (time trial, autocross and speed stop), a car show portion ("Design and Engineer" judging, which is very controversial), and a road worthiness check (50-100+ mile road rally event on public roads).
Todd Earsley (the RS's owner) has been competing in Optima events as long as I have, and has completed more Qualifiers and SEMA shoot-outs than almost anyone else I know. He has won his class many times, almost always podiums, and took his EVO 9 to as high as a 3rd place overall finish in Vegas at the big post-SEMA event.
Todd's goal was to use the Focus RS to replace his race-prepped EVO and use it to complete the rest of the Optima qualifiers this year.... and hopefully win an invite to the post-SEMA Optima Ultimate street Car Shootout in Las Vegas. This is where ALL classes and cars are combined for an overall "ultimate street car" winner. He will be driving the car to these events and we and other shops will be upgrading various systems between events, as his schedule allows it.
OPTIMA AT CHARLOTTE, July 30-31, 2016
With his his bike mounted on the back and his trusty canine co-pilot Violet, Todd drove the Focus 2500 miles to and from Charlotte Motor Speedway on the week of July 30th to enter the 2 day Optima qualifier event.
OPTIMA USCA Charlotte Motor Speedway event results: https://clubregistration.net/clients/usca/results/overall.cfm?eventID=7058&class=GTS
The results for GTS class are linked above. Todd said he fought with the handling (understeer), the launch control was buggy, and the oil temps were super high for him as well on track. He was even seeing high oil temps in the autocross portion, with 20+ minute waits between runs.
No changes had been made to the car yet, so it had the same brake dive and floppy OEM suspension as before. Todd remarked at how the Michelins were over-matched by the performance of the brakes (again, the best part of this car) but noted that the engine felt stronger than when he first drove it. Driving 1000+ miles to get to an event likely allowed the motor break-in period to be passed and the computer nannies unleashed all 350 horses.
He finished 8th out of 14 in class, so about mid-pack. Todd is an accomplished NASA TT and Optima competitor and I watched his in-car videos - he was pushing it to the limit, too. But for a bone stock car on absolutely the wrong tires, he did damned well. The hot tires in Optima competition are the Bridgestone RE71R and BFGoodrich Rival-S. Look for one of those on this car before the end of the season.
Todd's Charlotte Optima event highlight video
In the video above Todd narrates the in-car videos from his best autocross, speed stop and road course laps in the Focus RS. Great video, worth watching. He is a bit kinder than me in his opinions of the car, at least publicly, hehe. The understeer in the stock setup is apparent, but again, the brakes worked very well in all 3 segments. With better tires, some camber, and more spring rate it will surely improve.
Free RS Mod!
We missed this one but while at the Charlotte event, Todd found a huge decal placed over about 1/4th of the face of the stock intercooler. We have speculated that this might be used there to block airflow, lower drag, and eek out a tick more gas mileage by Ford, but after more research we found Ford places it there to prevent water (during a high water crossing - which should never happen in this particular car) from entering the intake tract and possibly damage the engine. Todd removed this blockage and it uncorked a significant amount of surface area of the intercooler heat exchanger, which can now see airflow and "do work". Apparently this is the one "free mod" that people can do for $0 to reduce inlet air temperatures.
OPTIMA AT COTA, Aug 6-7, 2016
Only one week later and it was time for another hot hot hot Optima event, this time at Circuit of the Americas... the Formula 1 track in Austin, Texas, better known as COTA.
On his way down to the event he stopped in at COBB Tuning and they fitted the Focus with their Accessport and a Stage 1 tune, where it made 330 whp in an otherwise bone stock vehicle.
OPTIMA USCA COTA event results: https://clubregistration.net/clients/usca/results/overall.cfm?eventID=7059&class=GTS
In the timed track event the RS had more grunt on the main straights with the added horsepower from COBB. The oil temperatures were even worse, however, and the 105°F ambient temps didn't help things. Drivers were overheating, cars were overheating, and the RS couldn't make more than 2 or 3 laps before he had to come in.
Todd drove well but managed only 11th out of 18 cars in the GTS class. If you look at the cars entered in this class it is some heavy hitters.... Mclarens, Corvette Z06s, and a 2016 Porsche GT3 RS was the overall winner. So he has a tough battle to fight in GTS with a bone stock Focus RS. Hopefully, with some smart mods, it can become a contender.
Todd's COTA Optima event highlight video
Once again Todd does a great job of compiling his best runs in the autocross, speed stop and time trial competition portions of the Optima @ COTA event in the video above. He talks about the problems with fluid temps and more in this video.
I understand that this series of posts looks negative. Sorry, not sorry. Our impressions just did not match the shiny happy opinions of many car magazine writers or forum fan boys. We don't have a lot of tolerance for the excuses of why this car has massive understeer, and the failings of the "RDU" programming were real. The RS has massive amounts of hype which, we felt, is not justified. It needs a lot of work to handle more neutrally, and the power delivery is very FWD-like.
This Focus is due back here at Vorshlag in a day or two, then we have less than 2 weeks to develop and build camber plates to fit this chassis and the coilover monotube shocks and struts we are using. Todd is racing it again at an Optima event at Road America on August 27-28th, so I will update with those results soon. Hopefully the improvements we have in store this time will improve the car's overall and GTS class standings to better than mid-pack.
This post has gotten too big so I am going to stop there and cover more next time!
Thanks for reading,
Terry Fair - www.vorshlag.com
|16 Aug 2016 03:24 PM
Project Update for August 15, 2016:
So my last post was not received well by some folks - it came off a bit inflammatory, but that's not what I had intended. The simple fact is I don't sugar coat my comments about any
car. That last series of posts has been shared and read thousands of times in just a handful of days. Some folks just watched the videos, and probably took some things out of context (short attention span Facebook addicts who cannot be bothered to read detailed posts).
Lots of comments on social media, ranging from thanks to hate mail. Many aspects of our track testing were questioned, so this post is a quick follow up to my last one to hopefully better explain our test process and first hand opinions, as well as explore some technical aspects that were missed by some.
MOST NEW CARS HAVE SOME FAILINGS ON A ROAD COURSE, TOO
I wrote my posts from a very narrow point of view of track worthiness in stock vehicles. Most cars in showroom form have several flaws right out of the box
that hold back their lap times and/or their on-track reliability, just like the RS. There are only a handful of sports cars built today that DO work well on track right out of the box: C7 Corvette Z51 (but not the supercharged Z06), Mustang GT Performance Pack (the base brakes can be killed quickly), and the Porsche GT3 to name a few.
I have a good example for this in a similarly priced car that I can share. One of the more track-able cars right out of the box when they were new were 6-speed Brembo packaged 2011-14 Mustang GTs (priced from $32-38K). We have done a lot of track testing in theses and of course they have their own unique track issues in stock form, that need to be fixed. In 2012 I bought a base model
2013 GT (for $25K new!) with the 420 hp 5.0L engine (which made 377 whp, shown above right) and the 6-speed trans. This car weighed very close to what the Focus RS did (3518 pounds, see above left). We purchased it without the optional Brembo brakes - it was a stripper model that was priced about what a Focus ST costs now.
This base model GT came with 235mm all season tires on 18x8" wheels. The the grip level of these tires with this power and weight was a complete joke (the Brembo equipped GTs came with 19x9" and 255 tires, which were a bit better but still too small). This 2013 had the base GT 13.2" front brakes (twin piston sliding caliper) and matching 11" single piston rear discs. To try to get a decent baseline "stock lap time" on the same set of wheels we had planned to use later, we installed a set of 18x10" wheels and 295/35/18 NT05 tires (2" wider wheels and 60mm wider tires, yet 6.8 pounds per corner lighter
per corner). We also installed an AMB transponder, some class letter/number decals, and then I entered the car in a NASA Time Trial event at Eagles Canyon Raceway back in October 2012 for its very first track miles.
The car was a handful of days old, still had paper plates, and the stock brake pads were brand new and at full depth. I did one 15 minute TT session to get a feel for the car, and it seemed to be working OK as I increased my speeds. It did have a bit of understeer (lacked front camber, like nearly all cars in stock form) but it was manageable. In the second TT session I turned it up a bit and pushed my braking zones, running a string of three 2:07 laps
in a row (which is fairly quick for a nearly
stock car at ECR). The problem was the brakes...
On lap 7 of the 2nd track session, with an otherwise brand new car and brand new brakes, the front pads came apart. The material had worn so low that the remaining chunk of front pad disintegrated and essentially exploded as I braked after a 125 mph straight into a very tight corner (T7). There was no warning; the pedal just went right to the floor then I went for a ride about 150 yards off track. Not fun! I limped it back to the pits and all of the pad material was sitting inside the front wheels (see above left). The rear brake rotors
on my wife's 2011 GT also "popped" that day - both rear rotors cracked clean in two! Granted, she was on race tires with full suspension and aero and running 1:56 lap times, putting more heat into the rear brakes. We later noticed that this rear rotor issue was a chronic failure and developed a 13.8" rear disc upgrade kit for these cars. On the black 2013 GT we soon upgraded the front brakes to the factory Brembos and that plus brake cooling, better fluid, lines, and better pads and it never had an issue with brakes again.
My point here is - MOST cars have some Achilles heel, some initial flaw that only comes to light when driven hard
on a road course. In my last post I pointed out several issues we noted on the Focus RS, when driven how I drive any car on track. Mostly I was disappointed in the factory suspension design, the understeer heavy handling, tires that were too small for the weight and power, the computer controlled "RDU" rear axle that didn't do what it was supposed to do, the high oil temps, and the somewhat lackluster lap times. The track performance we saw first hand just didn't seem to live up to hype and real world costs for these cars ($45K is a common price I see for a lot of RS cars), in my view. It had more issues than most, but I doubt it has anything we cannot "fix".
One thing to note, the two drivers who have tracked this RS - Todd and I - are not your typical casual Novice group HPDE drivers. We are both comp licensed NASA Time Trial racers, which means we are both pushing the HELL out of this RS in stock form. At most NASA events, the TT run group tends to have the fastest lap times of the entire weekend, as we are essentially always running qualifying
laps. So not everyone will likely see the same issues to the same degree - oil heat, major understeer - as we did in the RS. Todd avoided LFB on track when he drove it but still noted serious understeer in autocross and road course use at both Optima events he has entered.
Also, the RS wasn't all bad
. I did say that the RS comes with great brakes, but I neglected to mention that it also has really good ABS programming
as well - at least with the 300 treadwear tires we have used on it so far. Ford seems to do a much better job than most companies with their ABS programming scheme. So many other modern cars have somewhat lackluster ABS functionality (I'm looking at you, GM). I cannot overemphasize how well these brakes worked on stock pads and stock fluid. Normally I can ruin brand new factory brake pads and boil brake fluid in a session or two (my 2013 Mustang GT example above is not unique) but not this RS. The brakes were "Fair Proof", heh.
The factory clutch also seems to be holding up well
. Todd mentioned this in his Optima @ COTA overview video (the tail end of my last post), as he has now done dozens of "launch control" standing start launches. The AWD functionality seems to work fairly well from a stop. AWD is very important for Speed Stop and Autocross runs in Optima, where those two competitions and their specific course layouts tend to heavily bias AWD cars' launching performance. The image above showed the time slips autocross and speed stop runs he did in one day - a testament to the durability of the RS clutch system.
Todd did say that the complicated steps you have to go through to engage the launch control
were hard to do via the stalk mounted controls with gloves on. If you moved the car one inch you had to go through this multi-step process again. A little clumsy, but he is working with COBB to see if he can make that easier to engage (like the factory EVO launch control).
Again, we feel that our criticisms were well earned by the RS. The rear diff did not work right when I track it. The tires were too small. The suspension is sloppy and needs help. In the sections below I will try to explain in more detail what is needed and why. I will even explain why we used the tire pressures we used - because several folks questioned even that.
SECOND GUESSING AND BLAMING US FOR THE FOCUS RS ISSUES
I have avoided the dumpster fire that are the Focus forums, especially after my 2nd post. Why? Because I'm not really writing this thread for the typical fans of the RS. Those are folks who were deeply in love with the RS long before it was built, and made their minds up about this car long ago. Some will see any non-glowing review as apostasy. I am not going to ever shake loose some rigid opinions of how the RS handles or works on track - even if the majority of fans have not even driven one. I can't help those folks, and don't care to.
My Focus posts were written for readers who were open minded about all cars that might have an interest in buying an RS primarily for track use. Many have told me via the Book of Face that they appreciated our honest assessment of the track capabilities of this car. Others agreed to wait for any fixes we and other shops come up with - and these issue WILL BE FIXED, one way or another. We have an outlook optimistic, as we know there will be many improvements to handling performance and reliability in this car, just like we've seen on other chassis. I went back and re-read our development thread on the EVO X and it also had many flaws in stock form that were fixed. You can read about that in a section below.
There are many things we have been blamed of "doing wrong" to elicit the understeer, odd behavior of the stability control, and high oil temps on track in the RS. First, apparently I don't know how to press a button to switch between the car's "driving modes" (Track, Drift, etc). Next, I don't know how to press and hold a button to disable traction and stability control (this is the first thing I learn about any car). I also don't know the "right tire pressures" for a Michelin PSS tire. My Left Foot Braking technique was "wrong" and blamed for disabling the "RDU". Some even said I entered turns too fast, and should "enter slower and let the AWD pull you through!" A decent chunk of the comments were hard to decipher because of keyboard rage - but basically, I suck at driving and everything wrong I noted on track with the RS was my fault. "You're doing it wrong". Memes were even made...
Look, I won't ever convince some
folks that the world is round, much less that a bone stock Focus RS needs some help to go around a road course in a decent time without overheating. But you know what? I am fine with not being believed by a large swath of people - people who will never push their cars on a road course, nor ever need to use the solutions we will offer. It just is what it is. Some people just like to hard park, its cool.
"THERE IS NOTHING ELSE FASTER IN THIS PRICE RANGE!"
This is another claim many have made - that the $37-45K priced "RS is the fastest car available for the money". Of course that is very debatable, and when presented with other 2016 model cars that cost the same or less and DO go faster around a road course (see two below), the qualifiers come in.... well, "I live at the North Pole and I need AWD for driving in the snow". Or, "I need a back seat with 4 doors to haul my dogs". And on and on.
We get it - these two pony cars are in a completely different market segment than an AWD hot hatch
There are several choices in this price range that have faster lap times in stock form. But what about similar "hot hatches"? I mentioned several 4 door AWD competitors in my first 2 posts. Sure, that is the one thing I could have done differently, if we had the time and resources at our first MSR test day - I would have track tested some other hatch back turbo 4 door cars that day. This would be a logistical nightmare, but I will try to track down a few of the RS' competitors and wheel them around MSR under similar conditions on their OEM rubber. I am reaching out to some of our customers with similar turbo AWD or even FWD "hot hatches" to see if we can put them to the test at MSR and compare lap times. Because, in the end, the lap times are what matter most to me. How the car deals with the heat of road course abuse (cooling, brakes, and tires) could also be compared with these cars, too.
WHY TIRE PRESSURES ARE CRITICAL - AND IMPOSSIBLE TO ADVISE
One of the many things people have questioned about our initial track test in the Focus RS (and the list is long!) was the tire pressure
we chose to begin the testing with. And the basis for their reasoning I have seen posted is all wrong. Let me explain.
Left: Do not count on this sticker for track pressures! That is for MAX LOADING ONLY
To get to the initial tire pressure settings we started with, we looked at the recommended tire pressure decal on the door frame, shown in this video
. The numbers that Ford publishes are 46 psi, which are laughably high. These are actually there to prevent people from running their cars fully loaded at the rated gross vehicle weight limits on nearly flat tires - remember the Explorer/Firestone tire fiasco? The 46 psi numbers are the highest pressures
they recommend when the RS is FULLY LOADED TO MAX CAPACITY - with 5 people, a tank full of fuel, and the hatch area full of luggage. But these numbers are not for normal street driving and definitely NOT FOR TRACK DRIVING.
We noted that this car had 60 psi in all 4 tires
as delivered from the Ford dealer, which was part of the reason why it rode so poorly in our initial street driving tests. This was a mistake
on somebody's part - no sane person would run 60 psi on these MPSS tires for any sort of use. This particular RS likely had a porter or tech that performed a sloppy "make ready" service at the Ford dealership, and I suspect they should have lowered the pressures when this car came off the transporter down to a more reasonable 35 psi for regular street use.
Instead of of the "recommended for max load" 46 psi number, we started by setting all 4 tires to 30 psi cold
(the car was trailered to our first MSR track test, as shown below, so the tires had no heat in) and we were hoping
to see 40 psi hot
on the front tires after
coming in from hot laps (they did). The rear tires do so little work on this Focus that the pressures back there don't matter as much, but we still started with 30 psi cold and they got up to 38 psi hot, too.
This was an educated guess learned from nearly 30 years of tracking cars, testing tires, and building suspensions systems. We test a lot and have learned some good starting points for a variety of tires on a wide selection of cars - and more importantly what to look for
to adjust pressures after they are up to temp to try to find ideal settings. Cold settings don't mean much, what we are concerned with is HOT tire pressures.
We always adjust the hot pressures AFTER the first track session, where we also inspect the tires for shoulder scrub. If we noted the "tire scrub" line rolling down onto the shoulder, below the tread cap, we would add more pressure. If the scrub line was higher, and didn't use 100% of the tread blocks, we would lower the pressure to use more of the tire's working tread area.
Short video showing outside tire wear on Focus after first 8 laps
As you can see in the video above, which was taken with 83 street miles and only 8 laps on track at MSR (after my first track session), front tire wear was visible yet the rear tires almost had no wear. Most of the front tire wear was on the outer 3 tread blocks, yet the outer shoulder scrub line looked good. From that we knew we were pretty darn close on the tire pressures for the 235mm Michelin PSS, yet we had a long way to go to get this car to go faster on track (see suspension discussion, below).
|16 Aug 2016 03:25 PM
continued from above
Front tire wear after 83 street miles and 16 laps at MSR-C
This image above shows the total tire wear after our initial 16 lap track outing (two 8 lap sessions on a track surface with very low tire degradation), and the image below is after 2500 street miles 2 days of Todd racing at the Optima event. Overall the tires are wearing somewhat heavily BUT that's mostly due to the stock suspension losing so much camber in roll and too narrow of a tire for this car's weight. Overall this is about as good as we could expect for front tire wear on a 59% front heavy, effectively FWD, overtaxed and narrow tire that is losing 2-3 deg of camber when rolling in a corner.
Worn pretty poorly after 2 events but as good as we would expect considering the weight/size/suspension
To make this car faster in Optima competition - which includes autocross, speed stop, and time trial road course competition - there are several other settings we will alter to improve performance and tire wear. Then, once the tire killing suspension issues are improved we will ADD tire width, which should increase mechanical grip as well as deal with tire heat better from this car's weight and power level. Again, power has already increased by 10% (from 300 whp up to a dyno'd 330 whp after the COBB stage 1 tune). We explain the what and why we will change in the suspension below.
CAMBER SETTINGS MATTER AS MUCH OR MORE THAN PRESSURES
Track pictures make good data. This image is useful to tell us about camber settings, tire pressures and roll.
Tire pressures and camber settings are two of the most crucial settings a racer can alter to make the tires work more effectively, so we take these settings very seriously - we have to. We can only do so much with tire pressure changes, but a camber setting can make an even bigger improvement to tire performance and wear.
The ideal front camber setting for a modern radial tire will still have some
visible negative camber when loaded fully in a corner. The Focus goes to about +2° positive camber
under load, which is bad for both tire wear and ultimate grip - a significant portion of the loaded front tire isn't touching the ground. It is not "doing work".
Vorshlag is a multi-faceted business, but our primarily focus is to design and build suspension components
to improve factory built cars for road course use. As suspension engineers and designers, our main goal when creating suspension components is simple: make the tires work
more effectively. Everything we do with dampers, spring rates, adjustable camber plates, wheel widths, even chassis construction is done to optimize the tires when being driven on a road course or autocross conditions.
These 4 small contact patches of tire are the ONLY things connecting the car to the track surface, and we do everything we do to maximize the size of the contact patch (camber + tire pressure), and to make sure it isn't in the air (dampers + springs). "Tires in the air do no work" is a saying I use a lot, and if you look at slo-mo video of cars with poor dampers, the tires are not on the ground as much as you might think while cornering over even small track imperfects.
If you think about the pinnacle of motorsport - Formula1 race cars - they still use a LOT of static negative camber on their front wheels, which is visible in this Redbull F1 car above. Why is that? Don't these cars have the ultimate in suspension design? Ultra rigid carbon fiber control arms and carbon tubs that have zero deflection, metal suspension bushings that don't deflect? Double A-arm geometries that don't lose camber like a McPherson strut car does in roll? Super stiff spring rates, and THREE swaybars (front, rear, and FRIC) to control roll and heave? Yes, they have all of those things, and yet they still run -4° front camber, and on tighter street courses they run even more (Monaco). So it isn't unheard of for your Focus RS to need a lot more than the -1° it comes with from the factory. If we had the room we'd run the RS at -2.5 to -3° front camber on the otherwise stock suspension and tires.
On top of that, this RS is losing a lot of camber from roll and deflection (see below). One of the major problems we see in ALL late model, McPherson strut front suspension cars is a lack of camber control when loaded laterally in hard cornering. The front suspension bushings deflect and the soft springs roll so much that the car gets into a excessive roll condition. This makes the loaded outside tires start to roll off the ideal "flat" contact patch and onto the tire's shoulder.
This is not a tire/wheel position you ever want to see when cornering
The Focus is no different than almost any other "McStrut car" we have seen in the last 30 years - it loses a LOT of camber in roll due to several factors. A big part is the relatively soft set of springs and anti-roll bars used so that Granny Smith that buys one doesn't complain when she drives her RS down a dirt road to her farm house. Which means, in stock form, this car has a LOT of body roll. Next up is a big rubber bushing in the strut top mount, which deflects under lateral load, causing more camber loss at the tire. There are bushings on the lower control arm that also deflect under load (we will address this issue at a later date).
Left: Stock suspension too soft, lots of roll and camber going positive. Right: Much better with improved dampers, springs and camber
Here's a good side by side example. These two pictures above show McPherson Strut equipped S197 Mustangs in the same corner of the same race track (ECR Turn 11). We use this corner for a lot of testing because we can get great photos of cars here due to a placement of a flag stand nearby. The Mustang GT at left is bone stock (on 255mm street tires) and has a lot of roll and associated camber loss in the outside (left) front tire. The car on the right has a wider wheel and tire (295mm) yet has markedly LESS body roll and the loaded front tire still has negative camber when fully loaded. The car on the right has our fabricated Bilstein TrackPro kit
coilover kit (a modified Bilstein inverted strut & shock) with 4 times the front spring rate and -3° of static negative camber. The lap times from this shock/spring/camber plate change were 4 seconds per lap quicker than when using the same 10" wide wheel and 295mm tire, and tire wear was greatly improved. It was 8 seconds per lap faster than on the stock suspension and stock tires. And EIGHT SECONDS is an eternity...
Even the $50K+ BMW 1M was very front camber limited in stock form - this tire damage happened in one HPDE weekend!
Changing to coilovers, quadrupling spring rates, and going to camber plates is a pretty drastic change just to keep the tire from shredding itself in a corner. Sometimes, like on this BMW 1M model (above and below), we can keep the stock sized tire from getting shredded on the outer shoulders just by adding a spherical top mount camber plate. We had enough room in the strut tower with the OEM springs/struts on these E82/E90 M models to do just that.
We fixed the 1M with camber-caster plates - more from negative camber dealt with the tire wear easily
These 1M could see as much as -1.7° camber in stock form, but that still wasn't enough when you factored in the rubber top mount deflection, soft springs, and associated body roll. The damage to the tires shown above was from 2 days on track at a normal HPDE weekend, when driven by an experienced road racer pushing the car 10/10ths. With our spherical camber plates the camber adjustment went to over -2.8° while keeping the stock springs (they can get more camber with smaller diameter coilover springs). This small change - just one degree more negative camber and less deflection from changing out the rubber strut top mount - allowed this 1M and many more to stop killing front tires in one weekend.
We have do this "camber fix" on dozens of McStrut cars and hoped to do the same on the Focus. As my Focus Suspension Challenges video
from last time showed, there is just not enough room to move the OEM front spring inboard before it hits the tower, so we have to change to coilover springs
and new struts to allow for this much needed camber adjustment. That happens this week!
TIRE WIDTH PER UNIT WEIGHT RATIO
Another factor (other than the soft suspension) that is hurting the Focus on track, for both ultimate grip and especially long term tire wear, is the relatively narrow tire it comes with. The 235mm tire coupled with the 3450 pound as tested weight makes for a difficult "tire width per unit weight" ratio for the RS to overcome - and is another item we will address to try to lower lap times on this car. So many magazine writers fixate on power-to-weight ratios, but almost nobody ever talks about tire-width-to-weight ratios. Which, for handling, is so much more important than power!
Jarrett Jan's 2235 pound Miata on 225mm tires has more equivalent tire than our 3600 pound Mustang on 335mm tires?!
Some friends and I that autocrossed back in the 1980s-90s figured this out early on. We used to keep track of weights and tire widths use when comparing autocross times - because it was alarming how well CRX and Miata models did on slower courses on their "smaller tires" compared to more more powerful yet heavier cars we tended to race with. The truth was that these little/light cars had a HUGE tire-per-unit-weight advantage. Here's a quick calculation for the 2 cars above: a 2250 pound NA Miata on a 225 tire would equate to a 3600 pound Mustang needing a 362mm of tire for an equivalent weight to tire width! Even with the 335mm tires we ran at Optima events (above right) we were at a distinct disadvantage to this Miata on the same model and compound 225mm tire.
Let's do a comparison that isn't fair, yet is still valid. A C6Z06 Corvette with 505 hp weighs 3217 in this version (2012 model with factory optional 20" wheels). This is a big car, with 51%F/49%R weight bias has OEM 335mm width tires on a 20x12" rear wheel
(which weighs 8 pounds more than the Focus 19x8" wheel and 235mm tire). This is the rear drive wheels so they are critical on track. The Focus at 3445 pounds on a 235mm tire is at a huge tire-per-unit-weight ratio disadvantage.
To have an equivalent tire as the C6 Z06, the Focus RS would need to to be running a 358mm wide tire. Of course there are other variables at play, and the AWD system of the Focus should close some of that "tire advantage" gap in slow speed corners (autocross), but as we've seen the AWD advantage has almost no effect on a proper road course - unless it is raining, there are VERY slow corners, or the Focus gained another ~200 whp. Once you get off the super narrow OEM tires, we have found that AWD doesn't do almost anything on a lower powered car above certain speeds.
We have noted this in NASA Time Trial racing - once the cars are built to the limit of a power-to-weight ratio class, and tire sizes are no longer restricting the car, the AWD cars lose their advantages. They just... don't win many more events than 2WD cars. AWD really shines in dirt/gravel/snow, of course, but we don't road race on courses with much dirt, gravel or snow.
THE "FAIR" FOCUS RS TO EVO X COMPARISON
Bone stock 2008 Mitsubishi EVO X MR - with sticker power!
I want to get back to the EVO X for a minute - a car I compared the Focus RS to in my first two posts in this thread. This was a car that was very similar to the Focus RS in many ways, which we worked with over 2 years and made much better, and won a lot of autocross and time trial events in - a 2008 EVO X MR. It also had a few notable differences, but overall they were more similar than not.
Left: Inverted monotube Bilsteins on the MR were better, but springs were too soft. Right: Factory 18x8.5" and 245mm tire = 46.8 pounds
The EVO X was a $35,000, relatively heavy 4 door AWD car with a front weight bias - all similar to the RS. It has a turbo and intercooled 2.0L engine, beefy Brembo brakes (with 2-piece rotors), factory launch control (really a 2 step rev limiter, just like the RS), and rode on relatively soft stock suspension. The MR came with a slightly better shocks (inverted Bilstein struts, which have less strut deflection when loaded than a twin tube strut), the dual sequential transaxle (so nice, when it worked), and a more sophisticated rear suspension. It had a 245mm tire on a 18x8.5" wheel, so a very similar stock tire-to-weight ratio to the RS. It made 300 hp in stock form but with exhaust changes and a tune we got it to over 380 whp, which some are already able to get to in a modified RS.
I went back and read our EVO X development thread and I noted that we wrote that it suffered from similar "stock suspension" challenges, which are visible in the track and autocross images shown when raced it on the stock suspension, after initially upgrading to a slightly more competitive 245mm Dunlop tire on the stock 18x8.5" wheels. The car had a TON of body roll, front camber loss, and brake dive in this "stock suspension" autocross I raced it in, shown above. About the same as the Focus has, in all fairness.
In stock form it was pretty terrible, so maybe I was too harsh on the RS?
If so, here is my apology to Ford and the RS' fans... the EVO X was equally as crappy as the RS.
It just seemed like the RS had so much positive press and hype you'd think it was a space ship - but the EVO X was treated much the same way by car mags and forum fan boys alike.
We didn't keep the EVO X on the stock suspension very long, and after one autocross and one NASA Time Trial it got coilovers and camber plates. I was just remembering how much better it was the majority of the time we used this car over 2 seasons - with properly upgraded suspension.
|16 Aug 2016 03:26 PM
continued from above
Left: Enkei 18x10.5" wheel and 275/35/18 Yokohama was 48.5 pounds. Right: This big tire and wheel lowered lap times on the EVO!
The first things we did were add proper monotube coilover dampers, upped the spring rate, and lots more negative camber to the front end - which is the same order of mods we have planned for the RS. We then upgraded the wheels to wider 18x10.5" wide Enkeis with 275mm wide good street tires (Yokohama Advan AD07). Again, similar in tire width (275) and wheel width (9.5" or 10") we have planned for the RS. I don't think the RS can fit as much wheel as the EVO X, but we'll soon see after the coilovers are installed.
With monotube coilovers, more spring rate, swaybars, camber plates, and wider wheels/tires - this EVO X cornered flatter and was much faster
Like we have planned on the RS, we focused our changes on the EVO X on the same basic suspension upgrades - minimize body roll, reduce suspension bushing deflection, add negative camber, improve dampers and up the spring rates dramatically. Then we added wheel and tire width to improve mechanical grip.
This EVO X MR also had a major flaw on track
- we had to quickly make some cooling upgrades the MR's transmission cooler. The Getrag DSG semi-automatic trans ran hot on track (after 10-12 minutes it would overtemp the trans and go into limp mode) until we opened up the front cooling duct and added a fan. Like the oddly placed intercooler decal covering 1/4 of the front heat exchanger on the RS, the MR had a large transmission fluid cooler that was 1/2 covered up by a foglight. We removed the fog light, meshed the now larger openings (to keep rocks/bugs/klag from packing up the heat exchanger), and then added a 5" electric cooling fan to use in the pits between sessions to cool this fluid. Cured the over-temp issue and allowed the EVO to run complete 20 minute track sessions without fail.
So looking back on it, the EVO X MR we raced for 2 years was far from perfect
in stock form. With some work, a lot of testing, some upgraded components, and the help of others we were able to make it more reliable and much faster. Hopefully we can do the same with the RS. COBB did the tuning on our shop EVO X and they have already tuned Todd's Focus RS as well. Evolution Dynamics also has some tricks up their sleeve, as do other partner shops that are working on this car. It looks like we might just be able to cure what ails the RS. Stay tuned!
MICHELIN PSS SPECIFIC ADVICE AND 500 PSI
Like I said in the beginning, everyone on the internets seems to be questioning every single thing we wrote about in our first 2 posts. One of those was tire pressures we used on the stock 235/35/19 Michelin Pilot Super Sports, or MPSS for short.
This 300 treadwear Michelin tire is a great all around performance street tire, and while somewhat alignment sensitive, it tends to wear well over many thousands of street miles when used correctly. The MPSS can
work well enough on track, when the suspension is optimized, but this tire is by no means the hot "street tire" for track use. We recommend this tire for daily driver use to most people that ask because it is a quality tire, has decent performance, long life, and comes in a lot of sizes.
Currently there are probably a dozen tires in the 180-200 treadwear range that are faster than the MPSS: the Bridgestone RE71R, BFGoodrich Rival-S, Dunlop Direzza Start Spec II, Hankook R-S3-V2, Yokohama AD08R, and even Michelin themselves make several models faster than the MPSS. Because of our many years competing in Optima, Goodguy, and SCCA Street Touring classes, we have to know these tires very well and stay on top of any new comers or changes in the "200 treadwear tire wars".
None of these "super fast" 200 TW tires listed above are really appropriate for true "all weather daily driver use", as determined by most OEM car makers, so Ford went with a good compromise in the MPSS. This tire is an upgrade over what Ford puts on a LOT of its hot performance cars, so we have no complaints there - other than the narrow size they chose. A 245mm width in a 17" or 18" diameter would have been a more appropriate factory tire size for this car, given its weight and power level. But those 19" wheels had the look Ford wanted, so styling won out over weight, practicality or performance.
We have used many sets of Michelin PSS tires on many cars on track, as well as dozens of other brands and models, what we have learned is - there is no magic tire pressure
to run on all cars, even tires of the same model/brand. There are so many variables that affect tire pressure, it would fill a book.
Tracking with 245mm wide MPSS tires at ECR on BRZ
For example: on this lightweight (2775 pounds) rear wheel drive Subaru BRZ above was run on a 245mm MPSS for both street and track use on a 17x9" wheel (we later moved up to 255mm BFG Rival tires). After track testing we ended up with around 32 psi hot
tire pressures on the MPSS. These lower pressures can work better on lighter cars and/or cars with a better tire-width-to-weight ratio. We had really good suspension (MCS 2 way coilovers) and excellent camber (Vorshlag plates) and good swaybars on this BRZ, too. It cornered flat, had plenty of static negative camber, and a well supported tire of proper width for the weight and power - so it treated the tires well. This car with this tire had a similar weight-to-tire-width ratio to most Corvettes.
Left: 215 vs 245mm tires. Right: The FR-S/BRZ's main weakness in stock form were the craptasitc, skinny tires they came fitted with
Funny thing is - we made a big deal about how TERRIBLE the factory tires were on the BRZ and FR-S. I gave that car more grief than I did the RS. Of course at the time, this was scandalous - "Why do the magazine writers rave about this car if the tires are so bad??", they said. There were fan boys of this car as well, but the fact was that the skinny 215mm "Prius" tires they fitted to the 86 twins were a joke. Over time many thousands of BRZ/FR-S owners have upgraded to better 245-255 mm tires, which we recommended from day 1.
Toyota and Subaru missed a number of things on the 86 chassis design, which I was just as vocal about in that project build thread
. The ridiculously wide FA20 2.0L engine makes underwhelming amounts of power for this car. The engine is placed about a foot farther forward in the engine bay than needed, which helped contribute to the relatively poor 56% front weight bias - pretty awful for a RWD car.
Overall the 86 twins are still nice handling cars due to two important facts: they weighed in staggering 670 pound lighter
than the RS, and the track width is very wide for a car this light. Granted, the RS can likely eat this BRZ's lunch on a road course in stock form, especially with the little Pruis tires the factory fitted. By the time we were done this BRZ, however, it was an autocross and track terror with zero power mods. I ran laps as fast as the 420 hp 2013 Mustang GT at ECR (2:07s) in the 200 hp BRZ.
Honestly the "86 twins" are cars that people should also look at if they want to have fun on track or autocross. Yes, even versus the Focus RS. That seems crazy - it has 150 less hp and 2 fewer drive wheels - but this comparison can be made simply because the chassis is so much lighter. It has a decent suspension setup, lower center of gravity, decent RWD Torsen differential (no robots, computers, or NASA scientists needed) and again... it is 670 pounds lighter than an RS.
OK that was quite a tangent. Back to the MPSS tires and our starting pressures... My point somewhere in this section was: We get a lot of people asking us "what tire pressure should I run?". I mean hundreds and hundreds of people ask this, all the time, everywhere. Tire pressures, as I said above, are important but they are actually fairly hard to give gross generalizations about. Too many variables. And when people ask this question, they never tell us much about their cars, tires, wheels, setup, or end use.
It is even more frustrating on social media, where the previous day's technical help we post gets flushed down the toilet, and the same questions pop up the next day. Snapchat group think - ask, answer, forget, then rinse and repeat tomorrow. At least here, on a real forum, we can point to our answers from a previous post.
This has gotten so frustrating that we have created a sarcastic reply of "500 psi" to all tire pressure questions. Why? There are just too many variables that go into optimal tire pressures that it is impossible for us to tell folks what they should use - unless we get a lot of data about their car and we happen to have tested that tire model under those circumstances. Every car's set of variables is slightly different, and only long term, scientific testing can tell someone what their optimal air pressures are: for their car, on their tire model/width, there wheel width, their suspension/settings, and their track surface, their driving style/setup, and in their common weather/track temps.
So when you see our 500psi decals
, this is our way of saying there is no one right answer for tire pressures. You need to test for yourself, for your circumstances. Now you know.
Our true goal in writing these posts is to show fixes to the problems that we have seen on the RS. To make these cars faster and more reliable on track. My next post will finally have some solutions instead of just critiques and explanations.
So far this RS has logged 4400 miles and been run at 3 different road course venues on the stock suspension in the first month of ownership. The suspension will all change drastically, starting this week. Todd just dropped the RS off today for another 2 week period and we are working on our new Focus RS/ST camber plate design right now (for coilover use).
After pulling the engine undertray and front end off we have great "underskirt" pictures of the RS in new areas. Look for those in my next post.
With the front end off we are measuring for placement of a large external liquid-to-air oil cooler. We're going to try to fix that issue before the next track test and road course event. More partners have come on board with upgraded parts, after seeing this form thread and noting Todd's and our track testing. Lots of new parts will be installed in the next 2 weeks. Which is good, since Todd is running the RS at the 2 day Optima @ Road America competition Aug 27-28th
. We are hopefully going to be track testing the new suspension, exhaust and oil cooler before he leaves, so we have a tight deadline.
Thanks for reading,
Terry Fair - www.vorshlag.com