Initial impressions and review here: http://www.s2ki.com/s2000/topic/968713-subaru-brz/
I was a bit frustrated to say the least after my experience with the BRZ at the Streets of Willow Springs. Streets of Willow Springs is the tightest, lowest speed course local to me, and the car not only refused to rotate the way I wanted it to, but the sheer lack of power and corresponding inability to power out of turns was upsetting. Isn't a tight twisty course where this car is supposed to excel?!? So instead, I figured I'd expose the car to the exact opposite: Auto Club Speedway. The "roval" configuration at Auto Club Speedway combines about half of the oval with a more technical section utilizing the infield. Power is king here, and track consists of long straights, connected by simple 90 and 180 degree turns, and two chicanes.
tl;dr: Car lacks power. Lets go to a power track.
Stock alignment was measured at 0 degrees front and -1.25 degrees camber in the rear by West End Alignment. 215/45/17 Z1 Star Specs were again used on 17x8 Enkei RPF1 rims. Although my tire wear clearly indicated that the car needs more camber, there are simply no available camber plates or camber arms for this car, yet. XP10 and XP8 pads were again used, as well as Ferodo SRF.
New to the car are a Berk Technology dual exit exhaust prototype and secondary cat delete ("test pipe"). The two used together has resulted in a significant midrange power gain as well as minor weight reduction.
tl;dr: 2ndary cat deleted. Stock size Z1SS. Stock alignment.
The BRZ again proved to be easy to drive. The understeer tendency made for an easy turn 1/2, where most drivers are afraid of the rear coming out on them due to the extreme speeds (100+ for ANY current production car). The BRZ was absolutely drama free, allowing me to go through with no hesitation or feelings of uneasyness. The crowned surface of the infield combined with higher rear tire pressures (attempting to get the car to rotate) and insanely hot temps (107F ambient!) resulted in a car that ALMOST drove like an s2k.
Track analysis and thoughts
I had the fortune of having both the BRZ and S2k at the track for this event for a direct, back-to-back comparison.
Top speed for the S2k and BRZ were IDENTICAL entering turn 1. The S2k had significantly more prep, including a factory aero package (CR), 255 tires all around, and a track alignment, but more importantly, 55 more horsepower via an exhaust and tune. I was definitely entering the front straight faster with the S2k, but entering turn 1, I consistently hit 127mph in both cars. (I later hit 133mph entering turn 1 in the BRZ by utilizing a draft...) Conditions were similar: 100+ while driving the s2k, 104+ while driving the BRZ. The only conclusion I can make is that the BRZ is quite simply, more aerodynamic. While the S2k's Cd is unpublished, the BRZ's is 0.29. With the factory spoiler and "diffuser", this figure is supposed to drop to 0.27! This would certainly help explain Emilio Cervantes and Matt Andrew's times at Buttonwillow, and reinforces my theory that this car would be VERY quick at Buttonwillow and Chuckwalla. I wonder how it would do at WSIR, which IMO, is an aero track.
The BRZ definitely generates rear lift. How do I figure this? I was zero-counter exiting the playground, going onto the front straight towards the end of the day when the track surface was hottest. This is at the top of 3rd gear, where the car absolutely wouldn't be breaking the rear loose with just power. In fact, the car should have been plowing (understeering). Instead, it was driving like the S2k. I was, quite pleasantly, surprised. Does this mean that the car will zero-counter the turn called Riverside (infamous high-speed sweeper) at Buttonwillow?
The factory brakes held up spectacularly well. Whereas the S2k was on the verge of fading XP12 equivalent pads after two laps in the scorching heat with brake ducts, the BRZ's XP10 fronts didn't fade at all. Pedal feel was consistent and I had absolutely no issues with getting the car to stop. However, I've reached the conclusion that staggering the brake pads (XP8 in the rear) was a mistake. I was unable to trail brake for any of the turns effectively. The car simply refused to rotate under trail braking; instead it just plowed.
The BRZ desperately needs front camber. The front right tire was starting to tear (see pictures below) and both fronts were showing signs of rollover, even with highish tire pressures and them being a 215 mounted on a 8" rim.
The front bumper makes downforce. After the track day, the bumper's alignment was off in a way that indicates that the front is being pressed/pulled down.
My FTD was 2:04.x with a ~220lb passenger in 107F ambient, in the last session of the day.
I am far more impressed with the car after exposing it to conditions that are supposed to be the BRZ's worst enemy. The car is quick.
Next weekend I will be taking the car to Buttonwillow(13CW), the "gold standard" for Time Attack in the US.