I bought my 2015 WRX on April 1st and was immediately impressed with its handling. I couldn't believe how aggressive the turn in was and how the awd pulled it through the corners under power.
In order to get a better sense of how it handled at the limit I decided to take it to Lime Rock to see what the REX was made of.
I've been tracking BMWs at race tracks around the North East since 1993 (wow has it been over 20 years) when my 1993 E36 BMW 325is had 1,200 miles on it. My favorite tracks (in descending order) are Bridgehampton, Watkins Glen, Summit Point, Lime Rock, Pocono (various configurations). In 2001 I upgraded to a 1998 E36 M3 which has turned into a finely tuned track machine with Ground Control coil overs, camber plates, sway barbarians and some minor engine mods (nothing internal) that would not compromise longevity. On R Compounds this car can keep up with most of the modern high HP cars that other driving instructors bring to the track these days.
Preparing for the Track:
It was apparent that the brakes on the WRX would not cut it for track duty. I was initially going to take her to Watkins Glen which is killer on brakes and was apprehensive about pads, fluid and cooling. As it turned out I wasn't able to make the Watkins Glen dates and settled on running the car at Lime Rock for its first track date. Lime Rock is MUCH easier on brakes and there is only one very heavy braking zone going into Big Bend from the main straight. Still - brake upgrades were essential for the track.
It was very difficult to find any resources on what pad shape the 2015 WRX uses since the car is so new. Enter Justin at JSC Speed. They purchased a 2015 WRX as a development/project car for their business (they maintain the WRX safety cars used at NJ Motorsport Park's Lightning and Thunderbolt race tracks). To figure out what pads were needed, they took apart the brakes on their project car and test fitted a bunch of different shapes. It turns out the 2015 WRX uses D1078 pads up front and D1114 in the rear.
I upgraded the pads to Hawk HP+ all around. These pads have the most aggressive bite and best heat tolerance of any track/street hybrid pad and have acceptable squeal levels when driven on the street (unlike true race pads). I also upgraded the fluid to DOT4 ATE Super Blue race fluid which has a much higher boiling point than stock DOT3. I also upgraded the brake lines to braided stainless just for the hell of it since everything was apart and I was flushing the system anyway.
That's pretty much it.
At the Track:
Let me preface by stating that I have not driven a bone stock car on a race track in 15 years so I knew going in that a comparison to my M3 would be entirely unfair.
I pumped up the standard 235/45-17 Dunlop Sport Maxx RT tires to 40 lbs all around and got in line for my first session. I turned off all the traction control nannies by pressing and holding the traction button until both lights lit up on the dash. My car is a CVT (can you believe it) and I set the transmission in S# and put it in manual mode.
I took it slow, building up speed progressively over the first 4-5 laps. The car felt fantastic on the warmup lap and I pressed it a bit harder on each successive lap.
The stock suspension is very nicely sorted and the car does not lean much in the corners - even at the limit. The car and use a lot more camber in the front to get the front end to bite harder under extreme load but otherwise it was very impressive. The car also handled the transition from the left hander into the right hander pretty well and was very responsive to a small mid corner lift to get the front end to tuck in.
The upgraded brakes were excellent. The pedal feel was a huge improvement over the sponginess of the stock fluid and pads. There was still about 1/4" of travel but then they had great bite and a solidly firm feel after that. The brakes remained strong and never faded over the course of the day. They also felt balanced and had good modulation. I only got into the ABS twice all day when I really started to push the braking point closer in Big Bend and trail braked it thru the first apex.
I have to say that I was disappointed with the steering feel. The steering was accurate and responsive to inputs but I got no feedback through the wheel about what was going on at the front tires. My M3 is always talking to me, telling me how much grip is available before the front end starts to slide. The WRX felt more like I was driving a video game - accurate but numb. That was a letdown since I didn't feel that the wheel was numb during hard street driving.
The 235/45-17 Dunlop Sport Maxx RT stock tires are great - up to a point. I played with the pressure a bit dropping 2 lbs all around after the 1st and 2nd session to try to prevent them from overheating. I tried this because the tires never rolled over on the sidewall and it was very apparent when they got too hot because they would get really greasy. Toward the middle to end of the later sessions I had to continually adjust my turn in to account for the degrading grip and responsiveness of the tire. Still for the speeds that the car was running the tires held up very well. No chunking of the tread blocks or unusual handling characteristics.
The engine was strong initially and did a great job of powering through corners with the awd.
I believe I ran into some overheating issues on either the engine or transmission oil. I saw 243 to 250 max engine oil temps on the triple gauge readout in each session. I don't know about the transmission temps as there is no gauge for that. Either way the car felt down on power as the day progressed. Ambient temps were high 70s low 80s and partly sunny.
I think the computer must have been backing down on boost or timing as temperatures rose but this is just anecdotal.
The CVT transmission did all right for itself. It took me some time to get used to not heel/toeing on downshifts and using the paddles but the 8 speeds were pretty useful keeping the car in the power band (4800 - 5900 mostly). I used mainly 4, 5 and 6.
They did an excellent job keeping me in place with the stock belts. I used an old trick i learned before I installed a roll bar and harnesses in the M3. I move my seat all the way back. Twisted the belt buckle a full 360 turn. Then clicked in. I then slide my seat up to tighten down the lap belt. The twist holds it from expanding. The shoulder belt tightens at the first hard braking zone and then I was good to go for the duration.
The group I ran with does not allow in car cameras that are not mounted directly to a roll bar (no suction cup mounts) so I couldn't use my GoPro. I did get some decent data from my iphone data aquisition software but I didn't plug into the ODB port to get all the engine data. Lime Rock is 1.53 miles with 7 turns and a lot of elevation changes. A typical 1998 M3 would run in the 1:04s. The WRX ran pretty consistent 1:07s. Not bad at all for a first time out.