Project Introduction - April 20th, 2017:
Welcome to another of Vorshlag's detailed Build Threads, this time chronicling possibly one of the craziest cars we have ever built. Even though its is 4/20 day, this is no drug induced delusion - what started with more of a dare has grown into a wicked track car build for one of our customers. This car is called the Chainsaw Massacre
- and yes, I will try to explain the name (given by the car's owner) in the paragraphs below.
This E46 chassis getting a custom roll cage in late 2016
The goals on this build are similar to the factory 2003 BMW M3 CSL, just taken to the extreme: start with a BMW, shoot for lower weight, maximum power, maximum tire, maximum downforce, maximum brakes, maximum reliability. To that we are adding full safety gear (cage, halo seats, belts, fuel cell, fire system) and using a plentiful chassis that is easily replaced if damaged in a track event. This "big tire/big engine/big aero" combination is a simple formula which we have built around before, but this time we have a customer that understands the benefits, and very few class rules or budget restraints to hold us back!
This shows where this project is in April 2017, after 5 months of work (with a few long delays waiting on parts)
Target weight is 2600 pounds soaking wet, with the ability to add ballast for series that require higher minimum weights. Target horsepower is 750 flywheel (650 whp), using a large displacement naturally aspirated aluminum LSx V8 engine. Tires chosen are "the biggest DOT Hoosiers available": 335F/345R with the ability to use a 200 treadwear tire of similar size when required. We are also using the biggest wing that AJ Hartman builds (72x14"), along with a diffuser (for when the wing isn't allowed) and a mega sized front splitter, canards, and hood venting up front. There are a few minor "street car" concessions like roll up windows, working wipers and lights, to meet the bare minimum "street car" racing series rules. There are virtually
no racing class power-to-weight rules that apply to this build, but we're shooting for around a 3.5:1 to 4:1 pounds per horsepower - which is closer to a FAST sport bike than any production sports car. This E46 is built to run with McLarens on track.
Is this just empty smack talk? Before the 'Debbie Doubters' chime in, yes, these are all attainable goals using proven components and build practices we have used in the past. Our caged, metal bodied BMW E36 coupe with an LS1/T56 drivetrain and big CCW Classics shown above (the "E36 LS1 Alpha") was 2508 pounds
The power numbers used are from a proven 7.7L LS engine combination from HorsePower Research (HPR)
, an engine shop that I am a part of. We already have the 468" aluminum LS shortblock built, just waiting on the heads. No, we won't be using some "destroked" high revving nonsense, but a big bored, big stroke, standard deck block with sleeves. #MURCA We have proven the effectiveness of this tire package, the aero tricks, and more on our red Mustang as well as other track cars. This BMW will be one BRUTALLY fast car that should go, stop and turn like very few other unibody street legal cars.
We always take pictures to update our customers during their builds anyway, so why not chronicle the builds in detail for the public? Spread the insanity far enough and we hopefully find more like-minded customers. As with most of our build threads from the past 15 years, this one will be cross-posted to a number of forums (which we either sponsor or they like us enough to let us post there), including:
All of the pictures can be clicked for higher rez versions (#watermarked #triggered), so you can see the details. These build threads take a lot of time to put together but people seem to enjoy them, so I'm going to keep writing them up like this. If you don't like the way this is written, I'm not putting a gun to your head and making you read it.
[SIZE="5"]HOW THE HELL DID WE GET HERE?
The path to this balls-out E46 V8 build wasn't a straight line - it took 2 previous cars and several years of work with this customer to get him to trust us enough to build something this crazy for him. Things like the 18x13" front
wheels are borderline absurd. And while some of the pictures shown are just shown to make fun of silly fads, like #DollarBillzonDemLips, this is a serious build that will be a bit insane to drive.
Not everyone would want a car like this, or could even drive a car this light and powerful without a bunch of electronic nannies. This idea started after Mr. Chainsaw was frustrated with his supercharged track Mustang, which had heat issues on track - just as ALL boosted track cars seem to have. Overheating, heat soaking, unusable power delivery, high weight, low reliability, and high consumable costs.
After two years of improvements to the cooling system, packaging things to better vent the hood, and adding ever larger heat exchangers the Mustang was getting a lot better, but the weight was still fairly high and it was making for a frustrating experience on track for the owner. Just like we told him from the beginning, and what we tell everyone who wants to use a blower/turbo on track: power adders are great for making lots of horsepower for very short amounts of time, but they typically make compromised track cars. A power adder also doesn't make an engine MORE reliable... it does the opposite.
This highly modified Mustang (which he called the Chainsaw
) was run at many HPDE events as well as Optima Ultimate Street Car qualifier, where it was damned fast. The owner enjoyed the variety of contests they do during Optima events - speed stop, autocross, and time trial. So that series became a focus for a "dedicated race car" to be built in the future. Which is now.
Mr Chainsaw thought about a McLaren, but wanted something that could be built faster for less, and more unique. Once we had a detailed build plan and estimate for this V8 M3, we then cautioned him that driving this car would be fairly difficult. Jason convinced him to let us build him a "trainer car" to help sharpen his skills on track. The supercharged Mustang making 640 whp and was a just a damn missile
on track, using the power to pass anything on the straights.
A stock powered 1.8L NB Miata would teach him how to maximize corner speeds, braking, and patience! He set his ego aside and gave us the go in the Summer of 2015. Jason and I found this 2003 Miata and our team turned it into a trainer with full safety (cage, seat, harnesses, fire, remote kill switches), excellent suspension (MCS, Hyperco, Vorshlag + bushings, bars), upgraded brakes (NB Sport brakes, Vorshlag lines, custom cooling, G-LOC pads, Motul fluid) and track worthy wheels/tires (17x8" Enkei & 225mm Rival-S), and lots of cooling (Mishimoto rad, custom oil cooler, new water pump & hoses, etc).
The goal of the track trainer was a super reliable car that he (and others in his family) could use to "beat on like a rented mule" at track events, to improve and refine driving skills. He hired a driving coach/data analyst as well. We built this car in 17 days and it was actually quite a fun little project to be able to do a Miata "right".
Jon here at Vorshlag did the graphics (stripes, number boards, etc) on the Miata. Notice the chainsaw wielding mouse wearing a "Texas Chainsaw Massacre" movie-style hockey mask? You guessed it - this car is called Chainsaw Mouse
, and the "Texas Chainsaw Massacre" theme carried over into the V8 M3 CSL we are now building. The owner has been running this Miata for two seasons while the build plan for the E46 solidified, we found a good chassis, and carved out time in our shop schedule to dedicate to the build. Our head fabricator Ryan is doing 95% of the work on this project while also juggling the the '69 Camaro track car build
, plus does all of our cage fab work.
[SIZE="5"]BMW E46: THE PERFECT DONOR CHASSIS?
Some might not agree with using an E46 M3 Coupe chassis for a wild track build, but let me explain. While we could have started with a C5/C6/C7 Corvette chassis and made something equally as fast, and it might have even been "easier", that wasn't the right car to start with on this project. Why? The customer's wife already had a supercharged C7 Z06, and while its fun and fast, the "Corvette solution" isn't everyone's
While modern Corvettes have plenty of benefits, the also come with a few downsides: a SMALL cockpit, very low seating position, somewhat poor visibility, and extreme difficulties in adding a proper roll cage to the chassis (they don't even have a real floor). We can also make a steel unibody BMW lighter
than a full frame/composite bodied C4-C7 Corvette for the same amount of weight removal work ("body on frame" technology is one of the least efficient ways
to build a light/rigid chassis). Besides, you can't swing a dead cat at a track event and not hit 30 Corvettes. The roll cage issues are real. Corvettes are easily the most difficult car we build cages for due to the cockpit and greenhouse shape and difficult to access mounting points.
To build a safe roll cage away from the driver on a C4/5/6/7 Corvette you often have to move bars OUTSIDE of the body
After several discussions we narrowed in on a BMW E46 Coupe to start with, for a number of reasons. We think the modern BMW 1 and 3 series chassis are unique in their ability to become excellent track cars with V8 swaps, and they can take a LOT of power. We've proven that with the E36, E46 and E90 chassis many times.
Left: The BMW E90 swallows a Coyote 5.0L V8. Right: BMW E36/7 Z3 with LS1. Both built or heavily reworked at Vorshlag
Here's the list of positives with the E46 chassis.
1. Strong, lightweight unibody chassis with "good bones" to build upon. The roof panel is easily replaced with carbon (and the CSL came with carbon from the factory), as are almost all other body panels - and there are good options from the aftermarket. BMW made 4 million E46 chassis globally, which makes them both abundant and cheap.
2. The interior room, ergonomics, seating position and visibility are superior to most low slung "sports cars". These give you an upright seating position that is favored by many drivers. You don't "lay down in a coffin" like in a Corvette since the BMW passenger compartment is fairly large and spacious. This lets us build a roll cage much further away from the driver, which increases safety and comfort and gives us better entrance/egress.
3. These cars have a fairly efficient aerodynamic shape for such an upright greenhouse. It has a sleek coupé styled body with a short trunk, long hood, and generous cabin. The look of the E46 coupe is more modern and timeless than the E36 which is more angular and becoming a bit dated.
4. The E46 engine bay is 2" wider than the E36 and easily swallows an LS V8, and the stock transmission tunnel accommodates a large T56 transmission.
5. The suspension is pretty good (McStrut front, independent rear suspension), it has decent wheel/tire room (especially the M3), and the brakes are not half bad (with excellent upgrade options). Of course we won't leave any of these items stock.
We started hunting for a 2003 BMW E46 M3 coupe chassis (the same year they made the M3 CSL) and found this one locally for a good price in late 2015. Once the project got underway (Winter 2016) we began by cleaning it up and getting the frame checked before real work began. The early build details follow below.
[SIZE="5"]REINFORCING, STRIPPING AND CHECKING THE CHASSIS
This chassis was already partially stripped and had "seem some fun" in it's past, so it needed a good inspection, some squaring up, then a few preventative reinforcement fabrication tasks before major upgrades got underway. First we took the M3 to our friend's bodyshop to put on his chassis table, check the diagonals, and square it up before we began the roll cage installation. Then we reinforced a number of common weak sports on the unibody. After that we began to strip the interior in preparation for the roll cage, even removed the roof to replace it with a replica CSL carbon version.