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Vorshlag 2011 Mustang GT 5.0 - auto-x/track build (STX?)
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New Member

New Member

17 Apr 2012 09:04 PM
Do you need a tester for the Watts link? I'll pay for the shipping to my house.
I have been religiously reading your posts since I bought my 2012 V6PP in Dec. All your massive experimentation is awesome.
Could you say more about the WL? (when) I have been seriously weighing options for mine. It is DS novice currently, but this trial of ESP & STX is perfect.

Veteran Member

Veteran Member

25 Apr 2012 04:34 PM
Great job this past weekend at the Mineral Wells Pro Solo. Waiting for your report, but I'm assuming we won't likely be seeing you back in STX anytime soon.

The bus lot is not Toyo friendly and we were still fighting the same longstanding handling issue that wasn't resolved until a week later, but the STX results there are what they are. So are the ones from this past weekend :-p


Basic Member

Basic Member

25 Apr 2012 04:38 PM

I suspect they'll be staying in ESP as well. Very good showing considering they were on old V710s. It was nice meeting you and Amy (worked a corner with her) this past weekend and for the info you shared. Good luck and I'll keep reading this interesting and informative thread.

PS - none of the pics I took came out well, maybe next time.

New Member

New Member

25 Apr 2012 09:53 PM
I find it funny about you post needing more power for ESP, you need more power? Try driving with the anemic 2V! their's not enough bolt on's in the world to make this thing have enough power for ESP. Motor swap is a must in the future

Veteran Member

Veteran Member

27 Apr 2012 05:07 PM

Project Update for April 27, 2012 - Part 1: A lot has happened in the past week and a half so this might be a long-ish update. I will break it into two parts - ESP preparation work from a week ago to get the Mustang ready for the ProSolo last weekend. Part 2 will cover the ProSolo results and a list of new issues that cropped up. I posted some of these pictures below on the Vorshlag Facebook page over a week ago - I put previews of upcoming thread/blog posts on FB first, so follow us there!

ESP Rear Spoiler

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In my last "quick update" from 4/13/12, I showed a picture of some rear spoiler bracket and element parts we got from a circle track supplier, as well as some machined washers and struts. We didn't use that bracket or the spoiler elements - they were too tall for use on the Mustang trunk. The manufacturer's website didn't have any dimensions so we took a gamble and it didn't pan out. Oh well, the rear support struts and the machined washers were useful. Instead, we made an all new rear spoiler from scratch using some 1/4" thick plexiglass we bought locally and some aluminum sheet we had at the shop. If you haven't been following along, SCCA Street Prepared rules come from pre-historic times and still do not allow a rear wing, only a rear spoiler. It can be as wide as the widest part of the car (excluding side mirrors) and can extend 10" away from the body in any direction.

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This spoiler was built to fit a spare red Mustang trunk we located a couple of weeks ago - one we weren't afraid to drill into for the ESP-legal rear spoiler or for the upcoming TTS/AI legal rear wing. The trunk was set up on a bench at the same angle as it sits on the car, so it could be built while it was off the car. Some of the scrap aluminum we had at the time was anodized, which made it a royal b!tch and a half to weld to, so it wasn't the artwork-like welds you typically see coming out of our fab shop. No worries - it was strong, worked great at the ProSolo, and was built to an insane deadline in only a day and a half. It looks pretty good for a prototype made out of scrap, but the next one we make will use some virgin aluminum.

The spoiler bracket bolts to the trunk using four "nutserts" installed into the trunk metal with a special rivet gun. The four points are shown above, where the black lower strut supports are placed. This aluminum spoiler bracket extends past the trunk and covers the width of the rear of the car, to about the edge of the sheetmetal. It could be another 4" wider per side (to extend out to the rear fender lips), but we felt this was wide enough to make plenty of rear downforce to match the Leguna Seca front splitter. The lower sections where it overhangs the rear fenders was later trimmed out so it wouldn't rub the paint and some Xpel paint protection film was added to the fenders "just in case".

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Once Ryan had the bracket laid out and tacked up, he and the guys made a cardboard template for the spoiler element itself. It is 10" tall and laid back at about a 65° angle. The next step was transferring the template to the plexiglass sheet and carefully cutting that out. There's a trick to cutting plastic with a saw - too fast and it melts back together behind the blade, too slow and it won't cut cleanly. My cheap "one speed" jigsaw (he had to pulse it on-off-on-off) was a nightmare to work with and it eventually burned up the motor after about 40" of cutting. A trip to Lowe's produced a variable speed Bosch jigsaw that worked like a charm and cut the 1/4" plexiglass sheet like butter. Drilling holes in plastic also takes ... patience. They managed to get everything cut and drilled without cracking the plexiglass. The machined washers are placed on both sides of all bolted joints in the plexi and held up after a weekend of ~30 autocross runs.

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The plexiglass spoiler element was simply bolted in place - it was flexible enough that it did not need to be heated and bent to follow the curvature of the trunk or the two "bends" at the edges, where it meets the rear fenders. The struts hold the element well enough, but we might go back and mount two tension rods to the widest points of the spoiler, with the rods attaching at the forward edge of the trunk. A little testing (and video aimed at the spoiler at speed) will tell us if that is needed.

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The rear spoiler was finished up minutes before the car was loaded into the trailer Thursday night and it definitely got a lot of looks at the ProSolo. This was the first time we'd made a rear spoiler here at Vorshlag and we learned a lot. The guys were very careful during mock-up and construction (lots of painters tape used!), there were only 4 holes drilled for this part and not a single scratch was added elsewhere in the paint. Good stuff.

Bigger Wheels

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Another new ESP modification we added were 315/35/18 Kumho V710 R compound tires mounted to Forgestar F14 wheels in 18x11" (front) and 18x12" (rear) sizes. We had been eying Forgestar (a division of iForged) for a while now and decided to give these wheels a try for larger widths like these. We called the guys in California there and they knew about Vorshlag and our Mustang, and our propensity for using big wheels. After speaking with them for a bit, they wanted us to become a dealer. So now we are a Forgestar dealer - if you see anything in their catalog you like, we sell at their MAP price.

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They did a super-rush build and made these wheels (from flow-formed/semi-forged blanks they keep in stock) in an extremely short time frame for us. These were machined to our 5x114.3 bolt pattern, hub bore, and backspacing. We have done a ton of testing to see how far we can push wheel widths on this car and we sent them our specs... and no, I'm not sharing those with you. If you want wheels that fit like these, call us and we'll be glad to sell you a set. :) It's the only piece of the puzzle we can hold onto, and we've spent a lot of time and money learning these wheel specs on this chassis.

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Even being careful as we measured for backspacing, then calculated offset, we still missed the numbers a hair in the rear and had to add a small spacer. So ... that meant longer wheel studs in the rear were needed. AJ pulled the rear axles out and used our new 30 ton press to remove and install the studs. Now we have ARP long studs on both front and rear axles (and the front/rear studs are different spline diameters and part numbers, so don't just order 20 of one part). All of this final wheel fitting was happening as the spoiler was being built and other race prep work was being performed, all while we had customer cars coming for service and orders were being built and flying out the door. It was a hectic week to say the least.

That final rear spacer tweak got us to this fitment with 11's in the front and 12's in the rear. The front is too tight for 12's under stock contours, hence the 11's, but the rear has the room for a race application (I wouldn't recommend either of the above for a pure street car). I'm very happy with the wheels, which have insane amounts of front brake caliper clearance and a pretty low weight. I will talk more about Forgestar costs and weights in a future post - after we do some more testing on them. They worked flawlessly at the ProSolo and next we'll see how well they do at a banked/high speed track tomorrow - with a NASA time trial at Texas World Speedway.

Delays and Improvements

Now here is the part I hate. Many of you reading these posts have pre-purchased or put your "name in line" for some products we've helped develop on this very Mustang, including D-Force 18x10" wheels and AST 4150 shocks. Both of those products, which Vorshlag ordered in large quantities in 2011, are over 3 months late being built and delivered to us. We have already refunded many of our pre-purchase wheel customers due to the continuous delays. AST stopped giving me dates and we received news this week that the D-Force shipment was delayed yet again. That's after we were told that the container was already here in the USA at port! Now they're saying May 14th. I'm pulling my hair out in chunks! I just want to apologize here to anyone waiting on parts, and I did so publicly in this blog post yesterday.

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In that blog post I also talk about several improvements we've made to the Vorshlag branded products that we can better control deliveries on, such as several coating and plating upgrades we've made to various parts in our Vorshlag camber plates. Also, we finally received the machined and laser cut parts for our all-new S197 Mustang camber plates, which went to the electro-plater yesterday. I need these for my own Mustang and we have lots of patient customers waiting for these unique camber plates, so that was exciting. These should finally start shipping next week. So that's some good news to go with the bad. :)

Continued below...

Veteran Member

Veteran Member

27 Apr 2012 05:08 PM

Project Update for April 27, 2012 - Part 2: So the update above covered last week's preparation and this update will cover the ProSolo event. We bombed out to the 2012 SCCA ProSolo which was being held at a "local" site on Friday morning - Mineral Wells, TX, only 2 hours away. We arrived at 1 pm so we could help with registration or whatever else the event co-chairmen (Brad and Jen Maxcy) needed. Since we were a sponsor to the Texas Region SCCA for this event (we put up $ for Friday night's welcome party), we got to set-up our trailer and vendor table near the Lincoln Welcome Center trailer/Tech line and next to the giant "shade tent" that was being set-up late Friday. Only had to move our trailer 3 times to make room for everything there, heh. Weather was PERFECT after a brief rain shower Friday at noon, with temps in the 60s-70s all weekend and sunny skies.

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Once we got the Mustang unloaded, Amy went to work getting people to sign waivers at the front gate while I got the car prepared for tech. Several sponsor decals later the car passed tech and I got in line for practice starts on the tree. A ProSolo is an unusual autocross format where there are two mirror image courses run simultaneously with a drag race style "Christmas tree" start. You reaction time at the tree does factor into your course times, so "cutting a good light" is critical. The slower your reaction time, the slower your lap time is because the timer starts as soon as the light goes green, not when you cross the start beam like in most autocross events. It's not uncommon to lose 1 or more tenths of a second at the tree, so you strive to cut perfect .500 lights (or at least lights in the .5xx-.6xx range).

I took four practice starts on the new tires and had some pretty blah 60 foot times (2.2-2.4 sec) and reaction times all over the place, but I had one .510 light (a .500 is perfect, but anything .499 or quicker is a red light and you get no time... kind of like a DNF). This was after lowering tire pressures a good bit. Since our car was the only one at the event (160 entrants) on Kumho R compounds, I didn't have much good intel on proper tire pressures to run. I had raced on V710s in the past and remembered that after testing we ran pressures really low... like sub 30 psi, down to 25 even. ESP guru Mark Madderash agreed and said he remembered pressures being that low on this tire, but not many people have run them competitively in Solo in 5+ years.

Vorshlag ProSolo Picture and Video Gallery:

Practice time was running out so I went and grabbed Amy so she could take some practice starts, while we continued to play with tire pressures. She was having a helluva time with the tree and kept red lighting, so I bought her more tickets. After 10 practice starts she had the tree down and was popping off some mid-.5xx lights (she has cut perfect .500 lights at Pros before), but still struggling with sixty foot times (2.4-2.8 sec). We talked through the launch, which was quickest for me at 1800 rpm. I guess I have a slight advantage over her with literally thousands of dragstrip starts on R compound and street tires (a bunch of us used to drag race our street/autocross Mustangs in college, using our autocross tires). So I can't give her too much grief for that. I wasn't exactly setting record sixty foot times myself (my best all weekend was only a 2.20 - the best in ESP was a 2.0 seconds and Madderash cut 2.1-2.2).

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Friday night we stayed out at the event site late, grilling burgers and hot dogs for 100+ hungry racers for the Welcome Party. I manned the grill for 4 hours and still smell like smoke a week later. I met a lot of new folks from out of state that came in for the Pro, a surprising number of which said that they follow this build thread and loved our little Mustang. Grilling on the open-top little portable grill we brought was no match for this hungry mob, so for Saturday night's party another Texas Region racer brought a 2nd grill, and together we grilled hundreds of chicken, brats, dogs and burgers until 10 pm. We killed 3 kegs of Shiner beer over the weekend, as usual. :)

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Saturday morning many of us hurt - from eating too much food, from so much walking, from excessive beer intake - but we walked the courses one more time and then I headed out to work the course in the first heat. That was when Amy ran in L1 class, so she was on her own for set-up and had no help with tire pressures between runs. :( The tires crept up almost 10 psi over her 4 runs, so that didn't help. She looked timid behind the wheel, which I kind of expected from her hopping into our STX prepped car just with some big R compounds and a rear spoiler slapped on. It takes her a couple of events on an all-new setup to adjust, but I was hoping 12 runs this weekend would short cut that learning curve.

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She was fighting some fast women drivers in L1 and managed to snag 2nd place after her first 4 morning runs (2 left, 2 right). She drove her fastest runs of the weekend that morning, but one of them had a cone penalty - which she cleaned up that afternoon, but she never matched her best raw times from that morning. I don't have a single picture of Amy driving as I was working course when she ran. Unfortunately this was a pattern I mimicked, also running my fastest runs of the weekend in my first Saturday morning race heat (which you can see below in this 6 minute video - my 2nd left and right side runs there were my quickest).

PAX Results:

Unfortunately, that was the high point of the weekend, and the rest of the ProSolo event went pretty much downhill for both of us. The car developed some funky "Service AdvanceTrac" fault, the steering feedback jitters were rampant, and the poor stock limited slip devoured itself completely - by Sunday it was an open diff; we never got close to our Saturday morning run times. I was trying everything I had on every run, and my final two Sunday morning runs were .7 to 1.0 sec slower than my Saturday morning left and right side runs. Looking at my 12 class runs I cut five .5xx lights, five .6xx lights, had one .4xx redlight, one in the .7xx range, and a pair of cones. Meh, I never claimed to be a ProSolo expert; in 24 years of autocrossing (I uh... started racing when I was 2!) I've only attended 7 ProSolo events, and it never really suited my driving style (I just don't get much better over the course of 12 runs on the same course).

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Left: If you don't show up on 315's in ESP, don't bother. Right: "SERVICE ADVANCETRAC" fault

With the car's performance falling off like it did I was lucky that my Saturday morning times were still good enough to hold onto 2nd in ESP class for the event, and put me at 12th place in PAX standings. That was a bit of a shocker. Madderash slapped on a sticker set of Hoosier R6s Saturday afternoon (I would too, if I had them) and looked faster everywhere, dropping a second per side on his final two Saturday afternoon runs, which were his fastest of the weekend. I ended up .4 / .6 sec off of him per side, so a total of 1.007 sec back for the weekend. He got 2nd in PAX overall for the event, by a mere .002 sec, so he was driving very well. I was still VERY happy with my results and look forward to more battles with Mark and the other ESP racers in the future. :)

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Everyone had a bit of push in this corner, it seems

Amy's Saturday morning times weren't enough to keep her in 2nd in L1, however. After two of her L1 competitors improved dramatically on their 11th and 12th runs of the weekend (with sticker tires Sunday) that bumped her to 4th place out of 9 cars in class on the last Sunday runs. Not unexpected, considering how far off my times she was and how the car was sort of imploding. Here's the video of Amy's Challenge runs - which was the only in-car video we got from her all weekend. She was about 3.5 sec off of her own pace, ugh. My Sat afternoon and Sunday in-car videos contain so much foul language (from me fighting with the car - and losing ) I cannot post them, heh!

Somehow both Amy and I made it into the Challenges - she into the Ladies Challenge and me into the Gumout Super Challenge. Amy's times were way off of her "index times" from Saturday morning and she went out in round one. Mine were similarly "off" from my best, and I was paired up against #1 seed Andy Hollis - oh boy. Still, I gave him a run for his money and cut a .514 light on one side and even beat him back to the line on one of the 2 runs (I think he had a mistake), but he beat me enough on the other side to advance. As I came through the lights on my first pass the AdvanceTrac fault light was on and I had mere seconds to get to the staging lights - not enough time to "reboot" the systems, so run 2 was plagued by a wacky throttle (it kept cutting out and flashing lights). Oh well, just making it into the Challenge was a first for both of us, so that was cool. :)

I got a quick weight on the Mustang at full ESP prep using the SCCA scales, and it came in at 3467 lbs (car is on the scales backwards so ignore corner weights). The 4th gen F-bodies in class are 3200-3300 and the lone 3rd gen is 3100, so we still have the heavyweight in ESP class - but its nothing like the weight discrepancy we saw in STX class (with 2600 lb RX8s and 2750 lb BMWs). With ESP rules we can lose more weight now, too. After the trophy presentation we helped clean up the site (hauled 20 bags of stinky garbage to the dumpsters) then loaded up and headed home by 7 pm. Thus ended our exhausting 3 day race weekend, which we are still recovering from now as we load up for another race weekend. :)

Many Upgrades in Store

We have a laundry list of things to fix before our next ESP outing, and our guys here at Vorshlag have already tackled most of them this week including: more rear spring rate, rear differential rebuild (carbon disc upgrade - before we finally pull the trigger on the Torson or Wavetrac), and more. I will show the guts of the original factory diff, which was indeed coming apart. The steering rack has got to be reprogrammed soon, so we're trying to schedule a 2 week window of no events so we can pull it and send it off to Ford. There aren't many 2 week gaps in our schedule for months, so we might bite the bullet and buy a 2nd $1000 electric steering rack to have programmed. Ugh.

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So overall it was still a great weekend, I was just a little disappointed at how the car's performance (and our own) peaked early, then fell off quickly. The tires still feel fine, but they are no Hoosiers. We are going to use them for track events from now on, including NASA's Time Trial event this weekend at TWS. Before we run in ESP again the car will be on fresh 315/335 Hoosiers (there's even room out back for 345s). As expected every single car in ESP that weekend was on 315mm tires front and rear, including: four 4th gen Camaros, one 3rd gen, and two S197 Mustangs. I was the lone driver on Kumhos and two driver's were on Goodyears (that were sticker tires Sat morning but wore down to cords after only 25 total runs - these things are way too soft!), with the rest on Hoosier A6s - the default DOT Race Tire in Street Prepared.

Check back next week and I'll talk about the prep for this weekend's NASA event (rear wing uprights, full brake ducting, etc), which is wrapping up this afternoon up as I post this (I need to be on the rode to College Station right NOW). By next week we should be shipping any backorders on S197 Camber Plates, we might actually have a more solid date on the long overdue D-Force Mustang 18x10s (agh!!), and we can work on fitting the Moton Motorsport Pro 2-way shocks on our car with the new VM Camber Plates. We have 3 race weekends in June, including another Optima Challenge event - so that's another set of $1200 street tires (200TW) we need to buy. I might open a used tire store here, since I have like 7 or 8 sets of half-tread 140-200 TW tires from racing the Mustang in STX for so long.


Veteran Member

Veteran Member

27 Apr 2012 05:14 PM
TeamRX8 wrote:Great job this past weekend at the Mineral Wells Pro Solo. Waiting for your report, but I'm assuming we won't likely be seeing you back in STX anytime soon.

The bus lot is not Toyo friendly and we were still fighting the same longstanding handling issue that wasn't resolved until a week later, but the STX results there are what they are. So are the ones from this past weekend :-p





Congrats on last weekend - you killed STX class at the Pro. And yes, the Bus Lot is not Toyo friendly... it looked like quite the handful at that Tex Region event!

boss002 wrote:I find it funny about you post needing more power for ESP, you need more power? Try driving with the anemic 2V! their's not enough bolt on's in the world to make this thing have enough power for ESP. Motor swap is a must in the future

Always need more power. Always. :D

New Member

New Member

27 Apr 2012 06:45 PM
Terry now that your in ESP with me your going to have to get my name right (MADARASH).

Look forward to running against you again, Hope so see you at the Lincoln Spring Nationals.


Veteran Member

Veteran Member

01 May 2012 07:54 PM
madarash wrote:Terry now that your in ESP with me your going to have to get my name right (MADARASH).Look forward to running against you again, Hope so see you at the Lincoln Spring Nationals.Mark


LOL! Sorry Mark - looks like I've been murdering your name for years. Thanks for pointing that out.

We'll see you at the Spring Nationals.

Veteran Member

Veteran Member

01 May 2012 07:55 PM

Project Update for May 1, 2012 - Part 1: The day after the MW ProSolo we got to work on the Mustang prepping it for the NASA Time Trial event at TWS the following weekend. In this 2-part update I'll show some new mods done to the car for better track worthiness (Part 1) as well as talk about the TWS event (Part 2).

Front Brake Cooling

So one thing we've been meaning to do to the car for a while, and something I highly recommend to all S197 Mustang owners, is to fabricate and install front brake ducting. Now Ford Motorsport (aka: FRPP) has a kit that they sell for the 2010-2012 Mustang GTs that is made to work with the optional CS lower fascia we have (pulls air in from the lower foglight holes). Problem is, the backing plates included in the Ford kit have a tubing diameter that is too large to fit inside the common 3" high-temp brake duct hose, so users have to hack the hoses to pieces to make it fit. It also requires modification to the inner fender liners to route the hoses they include that wasn't legal in STX.

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For the longest time we held off on making our own front brake ducting because of the STX rule limitation, but I decided - to Hell with it. We change rotors and pads and now rear aero/trunk configurations between autocross and track events. How much harder is it to pull the brake ducting off? (if we even needed to) So Ryan and AJ built the brake cooling set-up above using steel some tubing we had (in a diameter slightly bigger than the brake hose), welded them to the OEM backing plates, then routed the ducting to the CS lower fascia foglight openings and through the fender liners - without cutting them. We found a gap between two liners we could use legally in ESP and routed them there, and zip-tied them to the swaybar - which moves up and down with the wheel, pointing the ducting to the back of the rotor. We checked it at ride height at full lock with the 18x11's on the front and it just barely cleared.

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And man, did that help! Running at TWS you do get some extra brake heat after coming off the banking and bombing into Turn 1 than stabbing the brakes, in excess of 140mph. The brakes felt GREAT and I was very happy with the extra cooling added. If someone sees something here that is not SP compliant, please speak up - but it looks legal to me. And its not like we need brake cooling in an autocross, so we can take it off it need be. We've made similar one-off brake cooling before so this was fairly easy for us.

High Speed Aero

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The rear spoiler (shown above, now painted black and weighing 9.3 lbs) we made for ESP class autocross use really has no business on a proper road course, and was only made to be used at sub-70 mph speeds seen in autocross. It was also made to meet the somewhat arcane rules of SCCA Street Prepared. The Wright Brothers had more advanced aerodynamics in 1903 than the SCCA allows in many classes in 2012, but hey - the rules are what they are. So that 10" tall rear spoiler is basically a big parachute, which does provide some downforce at low speeds, but at the expense of drag. This style spoiler is not at all efficient above those parking lot speeds. I know they use similar parts in NASCAR... see my comments above about antiquated rule sets. :)

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So I had this "3D" APR wing (GTC-300), a 67.5" wide carbon fiber monstrosity that we purchased a while ago (we've been an APR dealer for many years). I think I got it for the E46 TTD car, then we re-did our TTD class points with the current tire size (285mm Hoosier R6) and realized we didn't have enough points to do any aero. Then I talked about sticking it on the E30, then decided that putting a $1200 wing on a $2000 car was nuts. So it was just sitting here.

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The 3D wing shape is really made for use with coupes and sedans to sit lower then the roof height, where the greenhouse adds an aero blockage in the middle of the car and the airflow is compromised behind the rear window. So this style wing kicks up in the middle, behind the greenhouse, to try to capture air flow coming off the roof. Mounted 2-12" off the trunk floor (under the roof height) it is ideal for this type of situation.

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Then when we looked at using it on the Mustang this year, we checked the rules for classes where other S197 Mustangs play - NASA TTS and NASA American Iron (as well as SCCA Street Modified). We noticed that in each of these classed we can stick the rear wing well above the roofline (8" above in AI/TT, 6" in SMOD!), and a 3D wing isn't necessary if you can mount it up that high. But we had this wing on hand, so we made uprights to fit it to the car anyway, just to see how it would work and to verify the upright design that we had been tinkering with. We've since found out that we can get a flat style CF wing from APR for a good price and will likely go to that style wing at a later date, and use this 3D wing on another car where its mounted below roof height.

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The 2nd trunk we acquired for the ESP spoiler was re-used and now can be quickly switched from spoiler to wing and back. An outside designer, that is an aero specialist who has worked on professional road race teams as well as Bonneville record holder cars, helped us with the wing placement and upright design. After making wooden uprights to test the design and verify fore-aft placement (Tuesday) we took the 3D designs and turned them into engineering drawings (Wednesday), then had water jet cut parts made (by Thursday). Our fab team then tweaked and welded up the bases and uprights, then shortened some adjustable rod end struts for the wing adjustment, and fitted the wing to the car Thursday afternoon and Friday morning. Trimmed the wing at lowest angle of attack, loaded into the trailer for TWS, and were on the road by 4:45 pm - this made for a hectic few days of drafting fab work in the shop.

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We kind of neglected one variable (what's under the base, in the trunk structure?) and so we had to move the mounting bases rearward about 4" from where we had first laid them out, so the back of the wing does sit behind the car by more than the amount allowed in AI - but its still TTS legal. We're even street testing the wing this week - just to see how well the mounting base and uprights hold up to regular use (not that anyone would be crazy enough to drive on the street with something like this). As we get our hands on another straight style wing (not "3D") we will modify the mounting uprights for proper height, improve the adjustment range, and tweak the rearward placement of the wing to stay within AI rules (no, this car is never going to AI), just so we can say its an AI legal wing.

Other Wing Examples

Some people wondered why we simply bolted our wing mount uprights onto the trunk lid, so I shot several examples of other wing mounts at the same NASA TWS event. Many uprights passed through trunks and bolted to frame rails, others bolted to trunks directly but had supports underneath to the trunk. Like our car, others simply sat right on the trunk lid structure only. This is how we had to do it to not modify the trunk or to add structure underneath it, to avoid running afoul of ESP rules even with the wing removed. We did see some flex in the rubber bumpers that locate the rear of the trunk (height) at the back, which we will replace with custom Nylon bushings before the next event where we use the wing.

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Here's a Corvette with the wing uprights bolted right to the trunk panel, braced underneath. Above right is a G-Stream wing on a factory Boss 302S Mustang race car - also bolts to the trunk.

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Above we have a Fulcrum Wing on Mike P's 4th gen F-Body American Iron car, which won both AI races Saturday - handily. It bolts to the frame and passes through the trunk lid. Another wing is shown on a multiple time NASA ST2 winner's SN95 Mustang - this one with a wicker bill/Gurney flap, bolting right to the trunk.

Rear Diff Rebuild

So during and after the ProSolo (and looking back, at some previous events as well) I noted considerable problems with the OEM Limited Slip Differential - the Ford TractionLok, clutch-style diff. After the 30+ runs at the ProSolo with 315mm wide R compounds, it was toast. We had a handful of days to get a functional diff in the car before NASA at TWS, so instead of gambling on getting a WaveTrac or Torsen T2R in time, we went with a known fix and ordered the Ford Racing "Carbon Clutch" rebuild kit, M-4700-C. This is one of two kits that FRPP still offers for the 8.8" TractionLok, and the "C" version comes with upgraded carbon fiber fricton material and different steel plates for a whopping $108. The non-carbon kit (M-4700-B) retails for for $70 and even comes with the friction modifier, but the Carbon kit is the one to use for best performance; its even SCCA F-Stock legal, thanks to a TSB from Ford - we installed one of these in a 2007 Mustang Shelby for FStock class autocrossing a month ago.

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As soon as they pulled the old diff apart it was obvious that the clutches are done, as the friction material was coming apart. So the new discs were soaked in the fluid, then the discs and steels went in and the rearend was topped off with fresh 75W140 gear oil and friction modifier. OMFG that stuff stinks something fierce! The shop reeked of gear oil smell for 2 days.

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We didn't have time to do much testing on the rebuilt diff, other than a few laps around the parking lot. "Feels good!" I said, and onto the trailer it went.

Please check back tomorrow below for Part 2, where I talk about how all of this worked at the TWS Time Trial event...


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New Member

01 May 2012 08:05 PM

what wheel size and offset are you running to fit 335's on the rear?


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02 May 2012 09:18 AM
hotrod6731 wrote:

what wheel size and offset are you running to fit 335's on the rear?


Well all of these questions have been answered if you read my posts, but I'll do it again:

First, the rear wheel is an 18x12. The front is an 18x11.
Second, I'm not sharing the offsets, and I stated why in my post
Third, as I stated we were using a 315/35/18 tire at all four corners for now (that's the tires we had) but there's room for 335s in back, and likely 345s.

New Member

New Member

02 May 2012 09:24 AM
Fair wrote:
hotrod6731 wrote:

what wheel size and offset are you running to fit 335's on the rear?


Well all of these questions have been answered if you read my posts, but I'll do it again:

First, the rear wheel is an 18x12. The front is an 18x11.
Second, I'm not sharing the offsets, and I stated why in my post
Third, as I stated we were using a 315/35/18 tire at all four corners for now (that's the tires we had) but there's room for 335s in back, and likely 345s.

Geez n00b! Can't you read? Just kidding Rod. Looking forward to running against you this weekend in Atlanta at the Evo Shootout.

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03 May 2012 07:39 PM

Project Update for May 2, 2012 - Part 2: This entry will cover the NASA Time Trial race we attended in the Mustang test mule last weekend. The lap times were somewhat mediocre for most of my sessions with the Mustang only making about a dozen hot laps all day, but we had fun and learned a lot. This entry is sort of long, just so I can keep track of all of my thoughts for a later date. If that unimpressive opening hasn't put you to sleep, then keep reading. :D

It's now 4 days after the event and they still don't have results posted yet (color me shocked, heh). I can only go by the printed results sheet from session 2 on Saturday that I "liberated" during the event (it was an extra!). I have learned over the years that if you want to ever see class results for a NASA Texas event, you have to take matters into your own hands. For a group that runs such an awesome event, maintains schedule, and has excellent safety, they have crap results. Even after they are eventually posted (via the "MyLaps" site), you won't see all of the info that these results sheets show. I've bemoaned the poor NASA Texas race results before and will continue to do so until it improves, as a sort of Public Service Announcement. ;)

Sat, TT, Session 2 Results:

Amy and I arrived at the track late Friday (after 9 pm), due to leaving late and hitting 5 o'clock traffic in Dallas. I said 'hi' to a few folks, unhooked the trailer, then headed to dinner and the hotel. Saturday morning we got to the track at 7, unloaded the car and had it annual tech'd. Afterwards, I went to an instructor meeting at 7:30, the TT meeting at 8, and HPDE meeting right after. Since I was only there for Saturday, I got switched to a Saturday-only HPDE1 student, who also had a 2011 Mustang GT. Luckily she knew the track well, but not having run with NASA before it was an automatic DE1 placement (I signed her off to HPDE2 after 3 sessions).

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Our Mustang had several changes since our last NASA outing, where we ran it in TTB. This time we had the new stupid-high-mega-wing, the LS splitter, new 18x11/18x12 wheels and still-somewhat-fresh 315mm Kumho V710s (that we ran at the ProSolo). It was so far past TTB prep that it moved all the way past TTA and into TTS - which is the first of the "power-to-weight" classes in TT, so at least we don't have to nit-pick every point per modification. There were some other Mustangs in TTS already, including David Armstrong's well prepped Boss302 on AST 5200s and a real Boss302-S race car.

Relearning Texas World Speedway

After seeing the track briefly while riding along with my HPDE student in her first session, I quickly realized that I had forgotten all of my visual cues and lines from past outings at this track. Grass had overgrown the curbing, the surface was very different from my last time on track, and I had forgotten everything. Thinking back I really haven't run this track much in almost... 20 years? I co-drove the E36 Alpha car for 2 sessions with Hanchey back in 2008, where we got check out rides to get our TT Comp licenses. Before that I had run it a bit in the mid-1990s, but it was a completely different track configuration where Turn 3 joined with Turn 10. In the late 1980s/early 1990s I had run this 2.9 mile layout while still in college, but man... that was a LONG time ago.

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Allan and Ken's tandem E46 M3's were both fast, equipped with AST 4200s + Vorshlag parts and prep work

I knew it would take a bit to blow out 20+ years of cobwebs, so I gridded up behind AI speed demon Mike, from AST/Moton. HE knew this track very well so I figured I'd follow him for a few laps and... WHOA! He took off like a freagin man on fire, right on the warm up lap. So I got some heat in the tires, look back, and the E46M3 TTB Terror Twins KenO and Allan Page are right on my bumper. OK, OK, you guys go around... I'll follow them for... dang, mirror has more cars behind me, etc. Just trying to get my bearings but these TT guys are ready to RACE, like right NOW. I spent the first few laps of this session letting people go around me as a rolling roadblock and didn't get a single lap in unobstructed from the front or back. By lap 4 the car felt really loose on slow speed turns, and I smelled gear oil smoke and had a traction control fault, so I brought it in. I felt like an idiot out there, fumbling around trying to find some sort of visual cues on each corner. Ran an abysmal 2:01 best lap, which gridded me way back in the pack for session 2. Great.

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Here I am - the rolling roadblock, holding up the field :(

The first TT session was at 8:40 am and the sky was overcast, so the track was still stone cold. Turn 3 had no grip due to a Spec Miata that popped a motor there on the Friday 3 hour enduro, and it never felt good all day. Turn 10 (the carousel) was slippery as always. But the rest of the corners was mostly just... my crappy driving and generally terrible memory. Also, with completely new track set-ups and radical parts changes you inevitably have teething problems, and I quickly found one.

As I pulled into the paddock, the car reeked of gear oil. I jacked the rear end of the car up and it had gear oil all over the right axle tube, fuel tank, right muffler, and right rear tire. A-ha, that's why it felt squirrely and was smoking! We had just rebuilt the TractionLok the day before and the old "loop of hose" that was attached to the OEM axle vent wasn't enough to keep oil from filling the hose and coming out, especially after just topping off the 75W140 the day before and running on the insanely steep banking at TWS. Oil + tires = no grip! Talked to other racers with stick axle cars who had seen similar problems before - "keep driving it and it'll burn off enough fluid eventually!"

Luckily the Session 1 times for TT don't count for anything other than grid spots in Session 2, so I cleaned off the mess as best as I could - managing to get most of the gear oil on me. Ahh, gear oil - the world's worst perfume. I had to burn that shirt. Then I hopped in my student's car for her 2nd session and afterwards I went out in the Mustang again in TT session 2. This time I was gridded 16th out of 28 cars when I went out, and behind cars I know and was faster than before when we ran in TTB on street tires. Ugh, this session was going to be some work. I got some heat in the tires on the out lap and the car was responding better to the increased track heat (10:45 am) and a little better driving. I quickly caught and passed several cars gridded ahead of me (hence faster than me in session 1). My in-car video, a compilation of a few "offs" from other cars + my best lap (lap 4) is shown below.

Video from Session 2

That lap 4 was a 1:56 lap, after which I noted yet another AdvanceTrac fault and came in to reset it and check for more diff oil spewage on the rear tires. A sub-2 min lap was more in-line with what the car should do but still off the pace a bit. For example, KenO ran a 1:55.8 in a TTB car and Allan Page was right behind him, so of course I should have driven faster. David Armstrong managed a 1:53 in a TTS car, so I was still 3 seconds off the TTS pace (which is an eternity). Yes, there are several driving mistakes I made on that lap - but with this being about my 8th lap on this track in 4 years, with an all new aero package and all new grip levels, I wasn't too worried. Excuses... I gots em! :D

Since that session was cut short, I came in and re-checked the diff leakage - and it was once again wet with fresh diff fluid on the undercarriage and on the RR tire. Crap! I jacked it up, mopped up the mess again, then went out with my student once more. There were several after-session HPDE meetings and instructor/TT meetings and I talked to like 50 people I hadn't seen in forever, so it was a busy day. I wanted to show my student some changes to her driving line, so I took her out for a couple of 8/10ths laps in session 3 (taking a passenger is allowed in TT but it DSQs your times in that session, as does an "off" if you are solo) and we made it two laps before seeing more faults. With the student I ran a 1:59 lap and was hardly pushing it at all - I was working on my braking and line into and through T1 (which is tricky coming off the banking at 140-150 mph) and my apex kept getting closer to where it should have been into T4 and the T7-T9 complex... With more laps under my belt, I quickly realized where I was butchering all sorts of corners earlier. It just took a while to come back to me.

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Right: Mike's AI car was putting down 1:55 laps and he walked away from both Saturday AI/CMC races

Most of the TT guys went slower in Sessions 3 (and did again in 4), as the ambient temps climbed up to 90°F, so I wasn't going to find a stellar lap in session 4. By then I was also tired of the continuous computer faults and worried about more oil hitting the back tire (although I didn't see a drop under the car after session 3 - I guess it burned/burped off enough excess), so I let the car cool off, and talked to Amy. I was doing good to not have put a tire in the dirt in the 3 truncated sessions so far, given the oil on the rear tire, so I counted my lucky stars and we called it a day. We had a 4 hour tow back to north Dallas ahead of us and Amy was already bored after taking 200 pics, but not racing in TT herself. We packed up after my student was done (and checked out for solo in HPDE2) and hit the road right as the TT group was going out for their 4th and final session of the day.

Overall it this day at the track was a LOT of fun, and we learned a good bit about the new set-up (its faster than me on this track!). I had forgotten how much more stressful it is to run on the big banked turns at 140+ mph compared to the tighter, more technical, and slower road courses we run elsewhere in Texas - such as ECR, MSR-C, MSR-H, Harris Hill, TMS infield, and GrandSport Speedway. Still, we have VIR in July to contend with so I need to bring my game up at higher speed events pretty darned quick! :D

How Were the Upgrades?

As I stated in yesterday's update, the extra front brake cooling really worked. The brake ducts we added + the Porterfield R4 track pads Costas and others suggested (thanks!) were spot on. I only caught myself giving it a bit more brake pedal on one lap (lap 4 in session 2 - I'm talking to the damn video camera about it! I don't even know I'm doing this), after a mad dash into T1 at high speed (braking from 140+ to around 70-80). The rebuilt TractionLok just flat worked, even through the tighter/twisty turns like T3 & T4, T7-9, and the other tight turns before the front straight (T11-15). Even so, this car is still getting a better diff before the next big autocross (Spring Nationals) to deal with the tighter turns we see in autocrossing.

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Looking at the front camber it seems... barely enough (-3.8°). Gonna add more soon

I never felt the urge to adjust the rear wing angle of attack. We had it trimmed out at the lowest setting and it felt... very balanced. According to the CFD data it can generate 600 pounds at the highest AOA, but we had it trimmed down to much lower settings and it felt fine. This was hardly a proper aero test with barely a dozen hot laps run all day, so I will play with this the next time I have more track time. I really want to get a flat "2D" wing on there before we do any real aero test work though. For now... the wing seems to work, and other than the oil on the rear tires, the car worked fine (like in session 3 when it stopped puking on the rear tire). We had bumped up rear spring rate from 175# to 200# (that's the only stiffer spring we had on hand in this diameter and length).

What should the car have run? Well a 1:53 would have been more in line what several people feel the car was capable of - with a better driver. I tend to agree with them, and I know I was way off the pace for what the car should have been doing. If we had run Sunday and found some cahones ... maybe. I need more seat time at TWS to reach this car's potential, for sure. Put me at a track that I know better and I can get closer to the potential, I think.

Other Updates & Upcoming Events

I just talked to the folks at APR and there is indeed going to be a straight horizontal "2D" carbon fiber airfoil in 61", 67", and 70" widths, with an optional dual element 2D style wing. The pricing will be "more competitive" than the 3D wing (its probably easier to make) and these should be out sometime this year. I told them I want a 70" wide unit and that's what we'll perfect our wing design to use. Until then we'll keep this 3D wing on there with the current uprights for track events, goofy as it looks.

There are several events in May that we plan on taking the Mustang. Going to run the NASA TT event May 19th at Grandsport Speedway, located way south of Houston. This is an unusual "HPDE and TT only" NASA event, which makes sense on this smallish track. This will be the first time NASA has ever run there, so all TT class winners will set new track records. Hopefully I can find a little bit more speed (in the car and in myself!) and tighten the gap to the top TTS finishers. This is a tight little 1.3 mi track that I have run before (more recently than 20 years ago) so power and slippery aerodynamics (ie: Corvettes) won't be as big of a factor as it was at TWS. On May 20th there is another Texas Region SCCA autocross at TMS I'm going to attend, so that makes for a busy double-header weekend with a few hundred miles of towing in between. I plan to run both of those events on the Kumhos, so at least it won't take much prep changes between Saturday and Sunday.

Memorial Day weekend has a massive "Spring Nationals" SCCA Solo double-header weekend in Lincoln, NE. Friday and Saturday is the ProSolo while Sunday and Monday is a National Tour. The ESP class is already chock full of good entrants. We have to go to this one to see where we are, and we need to be on fresh Hoosier A6's by then, hopefully with some extra power and a real diff.

We have to have the updated programming for the steering rack before any of these events, as I'm tired of seeing the same nagging computer errors and steering wheel feedback. Now that we're confident this programming is SCCA legal I'm going to get it done. We will be pulling the rack out of the car this week to send it to Ford Racing, as the replacement $1000+ 2011 GT racks is on national back-order. Apparently there's a 3-4 month build date window where all of the early 2011 GTs are having similar "issues". Ford is not doing a recall yet, but probably will "eventually". If you are seeing this type of steering shudder CALL YOUR FORD DEALER and demand a recall/TSB. If you don't want to wait, call Ford Racing in Detroit. All of the World Challenge and GRAND AM Mustang's run this update programming, and it supposedly fixes the steering feedback loop shudder and related Traction Control system faults. We'll find out and report back soon!


New Member

New Member

05 May 2012 01:35 AM
To be legal in SP we would need the factory X-brace and the factory rear upholstery bits from the Leguna Seca as well.

Don't forget that if parts are discontinued, you can use reproduction stuff. A new Vorshlag product?

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16 May 2012 09:51 PM
dude, there are no 2600 lb STX RX8s, not legal ones anyway, low 2700 is as good as it gets

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22 May 2012 07:55 PM

Project Update for May 18, 2012: We've made some additional changes to the car and had an autocross since my last update after the TWS NASA Time Trial event. After we received the new Vorshlag camber-caster plates and the re-valved Moton Club Sports, we scheduled time to install all of it onto the Mustang, then went looking for an event to test the new set-up at...

New Parts for our Mustang

The newly revised Vorshlag camber-caster plates were finally complete at the electro-plater a week ago and after we fulfilled customer back-orders, we built a set for our own S197 Mustang (shown below).

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I was looking forward to the much easier camber adjustment these new plates would allow us. Plus we could potentially use the added range of positive caster, if we felt the need to add more than the +6.4° the car came with stock. The next bits that were finally ready to install were the Moton Club Sport 2-way coilover shocks. The AST 4150 prototype coilovers had served us very well the past year, but we were really pushing the envelope on grip levels in an S197 Mustang with 315mm R compounds at all 4 corners. Adding compression adjustment would be a tuning improvement and the additional fluid from the remote reservoirs would also help stabilize performance on longer track stints.

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These Motons had been purchased a while ago and were a bit unique in that they were built before the Moton acquisition and were an old design. The front struts had lower mounting flanges with massively slotted upper holes, which are not part of the current Moton S197 spec. I'm not a fan of slotted mounting holes as it reduces wheel/to-strut clearance and can allow the lower setting to slip under hard cornering. So after test fitting the front struts and new VM plates to check the available camber range (more camber travel than before), Ryan filled in the slotted holes.

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There was enough range in the camber plates and strut tower opening that we could actually use the stock sized upper strut mounting hole on the Moton struts, so the slot was filled with a steel "slug", fully welded, then ground smooth (on all four slotted holes). Again, this isn't something that needs to be performed on this S197 strut any longer. Moton-USA also installed custom valving and their new DDP digressive pistons for some extra rebound force at low speeds.

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Installing the Motons and their accompanying remote reservoirs, then aligning and corner balancing the Mustang, took the better part of ten hours. About two hours of that was the fabrication work Ryan had to do on the slots, but that's still eight solid hours of install and set-up work. These were far from a "just take it out of the box and bolt them on" affair - just like all remote reservoir shocks, which add their own mounting complications.

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The front strut installation was relatively straightforward and didn't require any cutting or surgery since the hoses were long enough to route under the frame rail next to the brake hard lines. This allowed the remotes to mount right up into the engine bay with no fuss. The struts were bolted up to the Vorshlag plates with stiffer 550 #/in Hyperco springs (up from 450 #/in) and went in fairly quickly. Of course we fabricated custom front and rear reservoir mounts, like we've done

  • Photo and Video Gallery:

    The day started off with a freak rain storm that wasn't on any forecast or radar and caught everyone off guard. Nobody was set-up for wet conditions, including the event organizers, and a small percentage of people left the event after getting soaked during the course walk-through. They delayed the start by 15 minutes and got all of the equipment dried out, while attendees dried off and made adjustments for the rain. The Mustang was still running on the 18x11/18x12 Forgestars mounted with tread-less 315/35/18 Kumho V710s, so we knew we'd be slipping and sliding until it dried out - if it dried out.

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    Luckily, we worked the first heat when it was totally soaked and continued to sprinkle a bit more, but when we made our four morning runs in the second heat it was beginning to dry. It was so wet somebody still managed to take out a timer at the finish. This club is a bit more informal than SCCA and you can grid up in paddock on your own, with the folks more experienced with this club wisely waiting until the very end of heat 2 to make their runs. Then they take 7-8 cars to the starting area at a time to make all four runs back to back. I wasn't so smart and was one of the first cars to the line, driving in slopping wet conditions. And yes, we left the wing on the rear since this wasn't an SCCA event.

    It was wet as can be when I ran and my 4 runs and they were all terribly slow, including a spin on my first run. I have video from these runs, but they aren't worth watching. Amy was smarter and ran a bit later in this heat when it was quite a bit drier - and she was 5 seconds faster than me in our morning runs. The people running at the end of heat 2 were getting an even drier course and were that much faster than her.

    Thankfully it was completely dry in the afternoon heats 3 and 4, and we all got some better runs in. Unfortunately Amy left the vidcam on for 2 hours after her final morning run and killed the battery, so all we have are videos from the morning session. In the video below I was riding with Amy on her 4th morning run, and continually admonishing her to PUSH the car harder. She wasn't being aggressive enough with the throttle, but during my morning ride-along she managed to drop another 1.5 seconds.

    In-car video on Amy's morning run #4 (she was 7 seconds quicker in the afternoon!)

    The afternoon runs were a bit better, but I didn't learn from the morning sessions and ran in the first sub-group again. The course was dry, but now it was dirty from all of the mud that washed onto the course from the nearby construction. There was about one third of the course that was covered in dirt when I ran, which had markedly less grip. Amy wised up and waited until the end of heat 4 to make her runs and was the last car on course at the end of the day. She made her fastest run on her last, beating the entire 3R class, and set the 2nd fastest time of the day. Nice! The only car quicker was a BSP-prepped E46 M3 driven by KenO, who is one AST/Vorshlag's super-testers. :)

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    Terry (at left) was sliding around but Amy (right) was doing nothin' but winning.

    In the dry afternoon runs Amy punished me by 1.3 seconds, so I was mired back in 4th place behind some SCCA regulars in SS Corvettes. But my placing didn't matter much to me - I was excited that the car was doing this well on a completely untested, new set of Motons. Getting skirted happens when your wife is this fast, and I'm used to it. :D

    Observations from this Event

    What good is going to an individual event if you don't learn something? At this NTAXS event we learned a lot about the new parts we had installed (Motons, spring rates), re-learned to never come to an event without proper rain tires (even the 275 Bridgestone RE11s would have been better on my first 4 runs than the bald R compounds), and I learned that if the club has "optional gridding" that you wait for the optimum time to make your runs! I also found out that if I over-pushed the Kumhos on 4 back-to-back runs that the tires can overheat and get very greasy. Again, watching more experienced folks that run with this club, they were pulling out of line to spray their tires with water to cool them off, something I needed to do. Oh well - live and learn.

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    One thing we could see from the spring rate and shock change was the front brake dive was less than before, as was front bodyroll. The extra 100 #/in front spring rate and increased compression and rebound settings we used (in the afternoon) helped there (ran the compression full soft int he wet session). Also, the new camber setting of -4.0° up front seems to be edging in to the proper amount, after looking at high resolution pictures of the outside front tire under cornering. As you know, a radial tire works best with a little bit of negative camber when fully loaded, so this picture is almost perfect. A tick more and I think we're there. I will keep an eye out at the next event (a week later at the same event site), when we've switched to fresh Hoosiers and see if it ever gets into to positive camber. If it does, we will add more static negative.

    We've always run a lot of negative camber on this car, as learned from testing. Even with street tires it responded best with over -3.3° of front camber. Some folks like to argue that S197 Mustang's don't need this much camber, but I disagree. Again - as a camber plate designer, this is one of the only things I really know well. :p Pyrometer data, pictures showing the tire loaded, and tire wear trump theory and internet wisdom, in my book. The S197 is not magical - it is just another strut car to me. And like many other McStrut cars we've raced and designed suspension parts for, this one needs more static camber the higher the grip levels go. With 315 R compounds up front we're seeing more grip than a GRAND AM or World Challenge race car, and we keep adding more negative camber than those race teams run to keep this big tire as close to vertical when loaded.

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    Another of the tests we did at this event was to look for any indicator of downforce at speed. I manged to snap the picture above when Amy was hitting over 60 mph on course and as you can see, the trunk was deflecting a good bit even at a low AOA on the rear wing (we can always make a LOT more rear downforce with a wing than a splitter can hope to match up front). We knew the culprit - the factory "trunk bumpers". These little rubber bushings are what set the height of the trunk at the rear when it is latched, and we knew from the TWS event they were deforming at speed.

    We had a solution in mind and the day after this NTAXS event Ryan made up a replacement set of bushings from some round Nylon stock I had purchased the week before. Chucked them up in the lathe and made a drilled and tapped hole on the underside to mount them to the mounting plate. After tweaking the length to get the trunk height set properly, they were bolted down and now we have no more deflection there. The wing uprights sit right near the edge of the trunk lid (which has structure underneath) and this should now be a more firm mount, and still stay within the SCCA Street Prepared ruleset (normally you build bracing from the trunk floor to the wing mounts, but that's a no-no for ESP class).

    My next update will go over the next week's prep, which included a change to Hoosiers and a gamble on rear tire size choice... using the largest A6 tire that Hoosier makes. I rolled the dice, so check back to see if that choice paid off!


  • Veteran Member

    Veteran Member

    22 May 2012 08:02 PM
    TeamRX8 wrote:dude, there are no 2600 lb STX RX8s, not legal ones anyway, low 2700 is as good as it gets


    Sorry, Mark - I blame it on getting old. 2600, 2700... it all kind blurs together in my brain. ;)

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    23 May 2012 09:50 PM

    Project Update for May 23, 2012: We've done a bit of work to the car since the last update, and had another autocross to test changes before the Lincoln "Spring Nationals" event this weekend. Let's get right into the new stuff.

    One of the changes we had planned to delve into if the car seemed to be ESP competitive was proper race tires. The defacto R compound DOT tire in SP is a Hoosier A6, but we had been doing well with a Kumho V710. The Kumhos have plenty of life left but work better as a road course tire than in autocross, so we pulled the V710s off of the 18x11/18x12 Forgestars and ordered some HoHos...

    Go Big or Go Home!

    Looking at the

  • Class Results:
  • Course Map:
  • In-car Video for Run 1
  • In-car Video for Run 2
  • In-car Video for Run 3
  • In-car Video for Run 4
  • In-car Video for Run 5

    The results don't tell the entire tale, of course. This is where I begin my excuses. :D So, as I've said before, this TMS site currently has construction happening right at the edge of the lot surface, with Jersey barriers holding back a mountain of fine, silty dirt from the lot. Every time it rains (which has been often here lately) it washes this dirt/mud mix onto the surface of the lot. So early drivers get to clean off the driving line, mid-day drivers get a cleaner line with some added track temperature, and afternoon drivers tend to see the cleanest line but the most track heat. If its a cooler day the afternoon runs are quickest. If its a warming day the mid-day drivers are fastest. That last scenario happened on this day - 2nd heat drivers were fastest by a good margin. It helped that our top National drivers ran that heat also!

    Terry-TMS-run2-052012-S.jpg Terry-TMS-run5-052012-S.jpg
    Left: Run #1 was quick. Right: Run #5 was my fastest

    I ran in the first heat along with about 1/3rd of the 109 racers. The first run in Mustang was with the stickers still on the tires, but that didn't seem to slow the car down at all. On that run I had trouble with braking in all of the higher speed stopping zones (super hard pedal - no power assist?) but put in a respectable run. My 2nd through 4th runs were either slower or not much better, with continued braking problems. My 5th run I finally adjusted my braking zones back significantly, went slower into most turns, and dropped 3/4 of a second from my first run. It wasn't pretty but it was faster. This was the only 42 second run of the heat and put me #1 in PAX for that 1/3rd of drivers as well.

    IMG1726-S.jpg IMG1779-S.jpg

    This was short lived, as Heat 2 drivers put in some phenomenal times and I dropped to 18th in PAX. There were two significant problems in my runs, and one "missing" problem. Well, other than my regularly crap driving, which goes without saying. The first car issue was a broken vacuum line from the JLT oil separator that was added in 2011. This part helps catch oil residue coming from the heads (that would normally pump back into the intake manifold) caused during high RPM use (7800 rev limit? Yea, that qualifies!). The problem was this JLT kit it came with plastic fittings and inflexible plastic vacuum lines that are prone to breakage.

    After my first run it I opened the hood and the catch can lay there askew, with the line or fitting obviously broken. I grabbed some zip ties an secured the unit but with this line wide open I was losing vacuum. A-ha! This is why I was losing brake booster assist after any long straights, hence the hard pedal. Eureka! I've been complaining of this issue at autocrosses for many months, back into 2011, so there's no telling how long ago this fitting cracked (see below for "the fix").

    DSC1075-S.jpg DSC1149-S.jpg

    Another issue was, as you can see above, the tire rub (then tire smoke) shown above. The 345/45/18 rears were both taller and significantly wider than the 315/35/18 Kumhos, and rubbed at two locations on the inside of the chassis - on the body at the forward section of the frame rail where it curves outward and on the rear swaybar. I would turn in, the car would take a set, where the axle would slide over and the tire would move relative to the rim, and the inner sidewall would start to "catch and release" the rub points - hop hop hopping through the long turns. This caused enough rubbing that it would smoke heavily. I kept an eye on it but there was little I could do other than drop out or keep going. I kept going.

    So I had miscalculated a bit on the 14" wide rears. They need to go out another 1/2" and then they'd look like Bubba going to the Drag Strip. We have the rear ride height compromised enough as it is for extra clearance and Amy said a firm "NO!" to flaring the rear of the car. So... when this set is gone we'll switch back to the 315 and tuck it all under the rear fenders. Again, I'm a fan of a narrow track for autocrossing, and this is very much "not narrow" at the moment.

    The one problem that was missing was... the traction control faults and steering feedback shudder. WTF? This is a mystery but I have noticed that the more wheel spin we see the more problematic the steering is and the more faults we trigger. With 345mm rear A6s and a fresh LSD out back there was dramatically less wheel spin. This is good, because both the OEM replacement and the FRPP race re-programmed steering racks (M-3200-EPAS, $1249) are on national back-order until June 23rd. We found one in the country after calling dozens of places, and they were saving it as a spare for their GRAND AM race team. Wouldn't sell it to us for any amount of money. So... we cross our fingers and hope this steering rack and traction control fault issues take a hiatus. :/

    IMG1681-S.jpg DSC1147-S.jpg

    We had been running with -4.0° front camber and I also noticed several pics showing the outside front tire loaded up at almost vertical, and not positive camber. Again, we're not using too much negative, and could even use a hair more possibly.

    Updates After The Autocross

    In preparation for the upcoming 4 day weekend of racing in Lincoln we knocked out these updates and repairs. First up was replacing the hoses/fittings and improving the mounting of the JLT oil separator.

    DSC1532-S.jpg DSC1617-S.jpg

    Ryan made the bracket out of aluminum and bolted it to open flanges on the valve cover, then bolted the catch can to that. He had one of our vendors make the lines and fittings and buttoned that up quickly. Looks like how it should have been from Day 1 - I knew better than to let that aluminum can hang from plastic hoses and fitting. Its funny how these obviously poor parts can come back and bite you in the ass... no idea how long this has been broken. Hopefully I'll have a better brake pedal from now on!

    DSC1614-S.jpg DSC1603-S.jpg

    Next up was the catch can installation for the rear differential fluid overflow problem we've been fighting at track events and even some autocrosses since day 1. Remember the fiasco this year from TWS, with oil spewing onto the rear tires? The little vent cap thing in the RR axle tube is a joke, and oil can and will come spraying out when it gets hot - and it will get hot at a track day. I bought this billet catch can and mount in mid 2011, and we finally got around to installing it. The factory vent was removed and a new fitting and custom made lines were fabricated by our hose vendor (who's a good friend of mine). Ryan bolted the catch can to the rear seat bulkhead and routed both the vent line from the axle and the "overflow" line from the catch can through a factory grommet in the trunk floor, on the driver's side just behind the back seats. Fixed!

    Some wider spacers were procured and the 18x12 wheels and 345 tires went more outboard, and look just terrible. If we could massage the inner fender areas we could make this tire fit, but that's a big no-no in the SCCA, so out goes the wheel. With a custom swaybar (legal) and 45 minutes with a sledge hammer (not), these wheels would tuck inside the fenders. GRR.

    DSC1590-S.jpg DSC1594-S.jpg

    Last up was foglight opening "grills". We had a customer's Boss 302S race car in the shop this week to do some suspension set-up work and we saw several great ideas on the car, including how they mounted the wire mesh grills in the foglight opening. These are functionally necessary to keep rocks and balled up tire rubber from hitting the evap core or radiator fins when lapping the Mustang behind other cars. The lower grill opening is also wide open from the factory and the evap fins on our car are already smashed up a good bit, and starting to happen behind the now missing foglights.

    DSC1619-S.jpg DSC1620-S.jpg

    Ryan took the tighter stainless mesh material we picked up a few weeks back and made some round sections slightly larger than the foglight openings, then painted them black. Then he drilled a series of VERY small holes around the round rear openings in the grill. Last he tied stainless safety wire thru these holes to hold it in place, just like how the 302S does it. Sometimes seeing something done simply makes a solution so obvious. Looks good, functions great, no more smashed cooler fins. The grills are almost invisible at this rez above, but clearly visible in person or in higher rez pics.

    Oh yea, the under-trunk carpet was reattached so we'd be extra-legal for the upcoming dual SCCA events.

    Many Upcoming Events

    There are several competition and track day events we have planned in the near future for our Mustang test mule. This weekend in Lincoln is the SCCA "Spring Nationals", with a ProSolo Friday-Saturday and a National Tour Sunday-Monday. After that we have a weekend off, followed by 3 straight weekends of racing in June:

    Looks like we have a busy month of testing ahead. Click any of the links above to find out about coming to watch or to enter any of these events. We'll have the Mustang at all of them listed above, and we will give ride-alongs on any run we take, if they allow it. Just bought a special set of 200 treadwear tires for the Optima event, we'll be running the big A6s in Lincoln one more time, and the 315 Kumho V710s for the other two track day events at ECR. I'll talk more about each of these events in future thread updates.

    Trailer is loaded, 11 hour tow to Nebraska tomorrow...


  • New Member

    New Member

    26 May 2012 03:13 PM
    Terry I hope things are going well for you guys today and yesterday. I look forward to meeting you tomorrow and taking photos of the stang tomorrow! :)
    Chris Jepsen 2009 Mustang GT #23 STX
    You are not authorized to post a reply.
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