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Old 08-29-2013, 11:33 AM   #11
Fair
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continued from above




SCCA Event Results: http://texasscca.org/2013_solo_resul..._final.htm#STU

I guess the BRZ was fairly well prepped for STX, too. I figured beforehand that we might give the two STU Mustangs a run for the money, and was hoping just to keep within a second of the fast STX guys that I watch in our region, like Brad Maxcy's BMW 328is and Mark Sipe's RX8.

Mark C (STU 150) and Amy (STU 197) ran their 5.0 Mustangs in the first heat of four for the day - which was both good and bad. It was good because the surface temperatures on this concrete lot were lower, as were ambient temps in the morning runs. This meant the tires wouldn't get overheated as quickly - but we still had to spray tires on both cars after runs 2-4. At least the didn't have co-drivers to add to the tire heat. But it was bad because the course surface for first heat wasn't as clean as it gets later. Texas Region SCCA does a phenomenal job in prepping the course, with multiple backpack air blowers and brooms, but nothing replaces car tires scrubbing the surface clean. And the course was a bit tricky. It was long, with a LOT of slaloms and near-offsets, perfect for narrow cars - more of what I call a "Miata-centric" course, which we see a lot since the course designer drives a Miata (love ya JJ!). It also had three increasingly tight 180° turn-arounds that joined long-ish acceleration zones. This was AWD heaven.

Walking it I could see the two STU Mustangs probably having trouble with corner exit traction compared to the AWD cars in their class, as the exits from each major "slow down element" (the three turn-arounds) were pinched off (aka: decreasing) and not what these cars need to "excel". The tightness of the 180s were also going to be tough to navigate in these big cars, as were the slaloms. But the BRZ on 17x9" wheels and brand new 255/40/18 BFG Rivals was almost as wide, at a measured 71" outer track width. So it might struggle through the slaloms, too.



It turned out to NOT be the case for the BRZ. This car was eating up the slaloms! In the video linked above (which has horrible audio, thanks to a previous gen GoPro HD camera) is my best run in the BRZ. It was a GRIP BUGGY, and at 2700 pounds with 255 Rivals, excellent shocks and great camber, I guess it should be. My first run in the BRZ absolutely obliterated both STU Mustangs. Now I did run in heat 4, so the course surface was cleaner. But it was also 90°F, so it was hotter when a ran, too. And I was co-driving in a 2-driver car with Matt, and we had to do fast driver changes - we barely had time to spray the tires, switch numbers and reset the seat/wheel between runs, and we had help (thanks, Olof and Mark).



So it looked like Matt's BRZ was pretty quick for having zero testing, at its first ever autocross. We basically threw a bunch of parts at this car, took some guesses at set-up, and went out there and drove it. Of course the parts didn't suck... custom spec'd MCS TT1 coilovers, 450#/in springs, Vorshlag plates, Whiteline bars, Enkei 17x9" RPF-1 wheels (15.8 pounds) and brand new 255/40/17 BFG Rivals. It needs a test day to get the bars, spring rates and other adjustments sorted, but we tweaked shock settings and tire pressures during the event and it felt pretty damned good.

This car was hooked UP on this course. At 2700 pounds the BRZ has a huge weight advantage on the 3600 pound S197s in STU, but with 166 whp it lacks a bit in the "go" department. I beat on that car like a rented mule, launching from the Start at 5500 rpms and taking it to redline several times on course; even using 3rd gear on most of my runs. These cars have relatively low power levels, but it just didn't matter. This is autocross, where WEIGHT WINS. In the end the BRZ was 3.6 seconds faster than Mark or Amy in STU and 1.5 sec faster than the winner in STU. That was shocking, and more than a little depressing. I mean, sure, I knew the BRZ could be faster but not THAT much faster than two well prepped STU S197 5.0 cars.

Matt, the car's owner and a 5 year veteran here at Vorshlag, is still a novice autocrosser yet beat the 30 car Novice class handily in the same BRZ. So I guess we had the car set-up well enough from the start. Co-driving the car with him in the last heat of the day made it tight on driver switchover timing, and the car slowed down on my last 2 runs - we think from both tire and brake pad heat (he had on the OEM pads and I was turning them to goo with my hectic Left Foot Braking). We just could not get the tires cooled down on our last 2 runs.


Left: Twin turbo LSx powered 68 Camaro on street tires! Right: 2 liters of naturally aspirated fury pumping out 166 whp. Its no Coyote 5.0.

PAX Results: http://texasscca.org/2013_solo_results/tr13_6_pax.htm

I will be the first to admit that I'm no "momentum" car driver, yet the times still PAX'd 13th out of 121, and won STX class by a 2.5 sec margin. My best run in the BRZ was run #3, still with with a passenger on board (took passengers on runs 1-3, then took runs 4-5 solo), so I know the car had more left in it. I feel that the tires were just a tick too hot, and word is the Rivals do not take extreme heat well - but what does well in Texas summer heat with 2-drivers running back to back? Not a whole lot. Normally you don't want to have a 2-driver car in any class in this kind of heat.


Amy driving the 2013 (at left) in the same 180° corner as Mark in his 2012 (at right).

Looking at the results, the two STU Mustangs were bringing up the tail end of their class. It seems that the Mustangs were very close to each other, and in the end Mark beat Amy by .009 sec, which is no small feat. Sure, Amy was coning runs left and right (3 of 5 runs) but her fastest run was clean and on her 5th and final attempt. Maybe her car's tires were past their due date (NT-05s were never that grippy), but she was hustling around that course and stepping on cone bases, cutting good lines. She's been racing since 1993 and often matches or beats my times, but she's a bit rusty in Solo this year. And in case you are wondering, I might guess that.... I might have put a second on her that day in that car, maybe. I almost never beat her by more than that, and we are often in the same tenth (or she beats me) when we co-drive together.



The image above (click or any other it for larger version, as always) is a "composite results" listing I put together of all of the STX & STU cars. I even dragged in some StreetMod and X class entries, that were really STX or ESP cars (but not the entire X or SM classes). Sometimes the online results disappear over time, so I like to make my own copy. This grouping shows all of the cars that matter to the STU Mustang. As you can see there was a good variety of cars in the STU class, including a 2.5L WRX, an EVO X, an E46 M3 (Gaith's car, which we have worked on several times), and the two Mustangs bringing up the rear. STU should be faster than STX, of course, but it doesn't always work out this way.

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