Project Update for June 4, 2013: So in my last project thread update above I talked about two more events we had run but that I didn't have time to cover, as well as some new products and developments that we weren't ready to talk about now. Since my autocross write-up ran long I'm going to start with that first, then jump to part 2 to cover a car show we were at the day before, and move on to "what's next" at the end.
SCCA Autocross at TMS Bus Lot, May 19, 2013
Amy and I took the Vorshlag TT3 prepped 2011 Mustang and ran it in the 3rd autocross of the year for the Texas Region SCCA, the day after we went to a car show on Saturday the 18th (see below). After not autocrossing for 6 months (other than my 2 fun runs at NOLA), we were both a bit rusty and wanted to go support our local region and have some fun carving cones. After signing up the first hurdle was: "What class do we enter"?
As you probably know, the Whiteline Watts Link we used before the 2012 Solo Nationals later didn't meet the SPAC/SEB's definition of a legal Watts Link for Street Prepared class, not for performance reasons but for semantics reasons, so that part now pushed us out of the class we ran in 2012, ESP. After that happened we added a few more popular but "illegal for SP" parts, shown below.
The limitations from the the various Solo classes we ran in 2010-2012 (STX, STU and ESP) were also hurting the competitiveness of this "multi-use" car in other motorsports events such as Optima Challenge, NASA Time Trial, GTA, etc. In late 2012 we focused this car solely around NASA's TT3 class - which gave us the freedom to add some of the more common rear suspension upgrades done to these cars by tens of thousands of S197 users. This included the rear wing we had previously swapped on for Time Trials, as well as aftermarket rear Lower Control Arms + LCA relocation brackets from Whiteline, shown below.
These two rear suspension upgrades are very common mods for solid axle RWD car owners, and don't cost a lot of money. The 4130 tubular steel
Whiteline LCAs ($269.99) and
Whiteline LCA relocation brackets ($107.99) total $378. That's almost exactly what one of our
315/30/18 Hoosier A6 race tires costs, but these suspension parts can fix a lot of problems with the rear geometry on these Mustangs. Consequently, they are two very popular S197 rear suspension mods.
The biggest improvement of all is in the lowest cost mod here: the bolt-on relocation brackets, which move the pick-up point on the axle-side of the rear LCAs down about 2". This changes the anti-squat geometry on these cars, which gets wrecked when you lower the rear ride height on this (and almost all) solid axle RWD chassis. These brackets are inexpensive and similar designs work on virtually all solid axle 3-link cars rather well, and many thousands of racers use them - but they just haven't made it into the SCCA Solo lexicon for ST or SP. I was curious how the car would respond with these two simple updates in an autocross environment, which were added after we left ESP class. And the Torsen T-2R differential we added after leaving Solo in this car as well. This autocross event would be a good test for all of these new bits. I try to see any event, even ones where we are poorly classed, as a possible test.
Left: Mike Simanyi's beautiful E36 M3, SM winner in 2009, was chock-full of AST/Vorshlag parts. Right: Blue tape classing!
We ended up running in Street Modified, or "SM". This refers to a category of 3 classes: SM, SSM and SMF. SM is for 4 seat cars, SSM is for 2 seat cars, and SMF is for FWD cars. The category was created in the 1990s, which is modern by SCCA terms, so it is much more up to date (and more modern aftermarket component friendly) than the older categories like Prepared, Street Prepared or Stock classes. Unfortunately this class is significantly more unlimited than ST or SP (it is a pretty big jump in the last step from ST to SP to SM), and allows some pretty major changes to the chassis, drivetrain, body and more.
Summary of the SMod Rules: http://www.moutons.org/sccasolo/Rule..._modified.html (actual 2013 Solo rules
here)
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Street Modified – The top of the “street” categories, Street Modified allows anything from Stock, Street Touring, and Street Prepared and just about any engine and drivetrain configuration as long as the engine manufacturer matches the body manufacturer (see Solo Rules for details). Four-seaters (BMW, Corolla, Civic, Integra, Neon, Supra, Talon, VW, etc.) run in SM and two-seat sports cars (Corvette, CRX, M Roadster, Miata, RX-7, MR2, etc.) compete in SSM. Carbon-fiber hoods, cams, turbo/supercharger kits, etc are welcome, too.
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The minimum weight in SM for a 5.0L naturally aspirated OHC motor like ours is 2200 pounds, which is about 1300 pounds lighter than our car is, without driver. You can have metal bushings/sphericals in all suspension pick-up points, custom spindles, virtually unlimited brakes and engine mods (even motor swaps within the same make), custom control arms, add aftermarket turbos/superchargers, composite body panels (hood and trunk), massive aero, remove all emissions, yank the back seats, and more. It is often compared to StreetPrepared, except you should always add "on crack" to the end, heh. I actually really like SM and have raced in it before, but to compete in this category at the top levels takes a purpose built car... way beyond what we have done to our Mustang. Radically lighter, more aero, more tire, and more power. Most of the SM winners at the Solo Nationals are in very light RWD cars with boosted engines or very well prepped AWD cars with boosted engines.
Our region has some fast SM drivers, almost all of whom are in AWD Subaru Imprezas with heavily worked engines and turbos - each one prepped beyond ASP class limits. We've even worked on some of them here at Vorshlag, and I raced against a lot of these guys in STU class for several years, from 2004-2009. SMod is also the "catch-all" class for cars too radical for ST or SP, so we get a lot of that, too. Kind of why we were classed there.
continued below