Last year some guy friended me on Facebook. That guy’s name was Bill Cook. He was telling me that he was getting one of the very first BRZ’s in the country, and asked if I wanted to autocross it. Naturally, I said yes, but it wasn’t until this weekend that I finally made good on that answer. We are still in progress with our build in New Hampshire, and since he was able to get his car down to Lincoln fully-prepped, and I was still in the process of building, I took him up on the offer to get in some great seat-time.
I’ve talked with Bill, and his build is quite public on FT86club.com. He has turned into one of the go-to guys for BRZ setup. He asks around, and he lets everyone know what is going on. Knowing that he has a BRZ that is close to what I would consider perfect for STX class as far as parts are concerned, I wanted to see what it could do on the Lincoln concrete surface. One of the unique challenges to Lincoln is its grip level. It is so high, that often times the settings most users grow accustomed to asphalt or uneven surfaces. Lincoln is flat pavement, with a very abrasive surface that is flat and for the most part, requires most users to increase the ‘stiffness’ to induce rotation, be it through spring rates, bars, compression, or a combination of all three.
We went into the event wanting to finish in the trophies. I accepted this challenge, knowing full well that there were several national champions in my class, most having driven RWD or their current car to their championships. This was my first rear-wheel drive car being used in national competition. I’ve driven RWD on occasion (3 times in total), but never in a serious manner dealing with complex setup, etc. I was coming from an STU AWD setup, where the big rear bar is king and the springs crush your spine if you attempt to daily drive it. Never driven the BRZ this way, let alone on a site like this. My biggest fear was the lack of power of the BRZ, and how it would stack up to the higher-powered BMW’s and RX8′s within STX. Turns out, the power is an issue, but suspension setup is much more critical with this car.
[I've found that when one learns the power of compression/rebound and use your buttdyno for adaptation to surface and conditions they will never go back to the 'ignorance is bliss' driving method.]
Bill was running with the following modifications to the car (that I know of, and he can correct me if I am wrong).
- KW Variant 3′s with 400lb front and 320lb rear springs, straight out-of-the-box valving
- Nameless Exhaust and Equal-length Headers & Tune (EcuTEK)
- 20mm adjustable Whiteline front sway bar
- Stock rear swaybar
- Kartboy lightweight pulley/endlinks
- Dunlop Dureza ZII’s (255-40 R17)
- Rota Titans 17×9 [beautiful bronze, not that it matters 'cept its dead sexy]
- Stock brakes/calipers/pads
- More magnets for sponsors than you can carry in one art case
- [and he has more, but all for comfort/convenience that won't matter here. See his build thread for details.]
Initially I’m running in cold conditions at the Lincoln Pro, and Bill brings me the car. I take it out for a few quick test-track runs and immediately notice something.. It pushes. More than I expected, more than a BRZ with just swaybar upgrades. Huh, I think. “Why does it push under hard braking so badly, and why is the turn-in a bit slower than I expected.” Wait.. let me get into driving styles first, because it will explain the reasoning behind Bill’s initial setup coming into the site.
There are two basic RWD driving methods (or really, autocross driving methods).. The first is the ‘pitch and catch’ method. This is often used by drivers with an aggressive approach. The premise is to toss the car into a corner, using compression to drive the kick of the rear end, and is usually fairly abrupt. It is very effective for high-power vehicles because it allows for the user to basically auto-pilot and step on the go-pedal as soon as they feel the back end lose grip with the surface. The other method is what I will call a ‘steady maintenance’ or ‘loose’ setup, which involves using more bars for lateral stiffness in the rear, or a greater ratio of rear bar to front bar, to induce a faster, but more predictable, release of grip from the surface, but it requires a user to ‘dance’ with the car with much smoother inputs of steering and braking. Every driver is different in their preferred approach, but usually it falls somewhere between these two.
Turns out, Bill leans towards more of a pitch/catch driver and I fall towards the extreme of the latter approach, with my LFB being natural after rally driving, and having a looser car my preferred. Bart is closer to Bill than I am. As such, we had to play with a few things to get it into the setup we each liked. The only downfall was the stiff front bar, which I believe was a simple mistake in setup as far as I was concerned.
[Morning was wet at the second day of the ProSolo, making car setup a challenge.]
We had wilding varying weather conditions, from completely wet to hot and dry, so we were able to adjust as needed, but the push was always present, and some turn-in sharpness was lacking. But, for me, I found a setup at the end that I liked and I wish I could have played with more in the dry. Let me tell you what worked for my loose setup:
LOOSE: We disconnected the front bar. Shocking, I know. But it was making the car push so badly. Given that my last run of the tour was the only one on this setup, I still have some adjusting to do. We ran on just the stock rear bar, and it was plenty tail-happy. To adjust for removing the front bar, we added 8 clicks of compression (from full soft) in the front, and were running 1 click of compression up in the rear. Rebound was centered, but could have been adjusted more had we the time and runs to do it at a test and tune in those same conditions. But the car came alive, and being that I finally got the pedal dance to work for the last day of the tour, I was so happy I could LFB without having nannies interfering and putting me ‘limp’. We adjusted the rake of the car to be lower in the front than the rear ever so slightly, for better initial bite and to also loosen up the rear end for Bart/Bill’s setup. Tire pressures were set to be 33 in the rear, and 32 in the front. [The pedal dance to release the nannies and put the BRZ into diagnostic mode is different based upon when you got your BRZ. Some it is pull-pull (hold), push push (hold), pull pull (hold), push. (pull is e-brake, push is brake pedal). Others have it as a combination of 3 and 3 (not 2 and 2). Didn't figure this out until the tour. facepalm
PITCH/CATCH: We put back on the front bar, and adjusted the compression to be dramatically higher. We had a ratio of 5 higher in the rear than the front. I cannot give you an exact number on compression as we were constantly adjusting between runs, but if I remember right, we started as up 6 in the front and up 8 in the rear, and ended up being up 12 in the rear and up 7 in the front. The rake stayed the same, but tire pressures differed. Tire pressures were 34 all-around in the Dunlops.
We took home trophies in both STX and STXL, and I made the Ladies Challenge during the Pro. I'm quite happy to have found a good setup that works for the BRZ on the Lincoln surface, and the one thing I'm going to change with my setup is that on the Racecomp Engineering Tarmac II's (Re-valved KW varient 3's) with an adjustable rear bar (whiteline 16mm) and a big solid front-bar (20mm whiteline) and 400lb springs all-around. I will be running a little stiffer to compensate for the front bar, but overall it should give me a linear step-out. I also have sway bar adjustment in the rear to get the car to rotate. Valving is different so that will not translate directly, but I keep in mind the lessons learned from Bill's car. I will also be changing out tires, because while the Dunlops were the tire to have before, the new kid on the block, BFG Rivals, appear be a better tire for my loose & smooth driving style and for the surface in Lincoln overall. We were the fastest Dunlop runner in my class, but I'm sure we would be faster on the Hankooks or the BFG's.
Thank you Bill for your help, and for our sponsors that make this possible: Kartboy, Nameless Performance, Racecomp Engineering [for Bad Panda] and countless others. I had a blast, and now a $500 paperweight of a trophy to remember the event. Minor tweaks and we both will have cars to watch in STX. Two different styles, two different setups. All national trophy possible.
Oh, and I f*cking love RWD. Just sayin’.