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My best pressures were at about 29F, 31R hot. The TPMS seems to be off by around 2 psi as it gave me a higher reading. According to the TPMS I was at 31F, 33R. Any higher and I had no grip and lots of understeer. It also helped a lot when I put the suspension on the harder settings and ESC off. It finally started to run almost perfectly on my 4th out of 8 runs.
I ran another event with Michelins that I set to 31F, 34R at the start of the run so they would heat up and end at closer to 32F, 35R (with a lot of overshoot on the first runs).
For fun, G-meter said 1.32/1.33 lateral, 1.23 braking G. I have no idea how accurate that would be, and given street tires on a street car those can't be true sustained force. There's a huge amount of grip in smooth sweepers, but not that much...
I ended up 5th of 85 in raw time, right behind an ASP Cayman with Hoosiers. 7th in index time, behind two national trophy winners, but ahead of a 5-time national winner. For proper SCCA competition I assume people would put 19" wheels with RE-71Rs on, rather than a completely stock car. I still think there is a lot of time to be gained from my driving better (this is always true, but I mean 0.5s or more).
I ran another event with Michelins that I set to 31F, 34R at the start of the run so they would heat up and end at closer to 32F, 35R (with a lot of overshoot on the first runs). Insertion pyrometer used after 5th run again indicated center tire temps were between the inside and outside. I use an Intercomp tire gauge, not TPMS.
For fun, G-meter said 1.32/1.33 lateral, 1.23 braking G. I have no idea how accurate that would be, and given street tires on a street car those can't be true sustained force. There's a huge amount of grip in smooth sweepers, but not that much...
I ended up 5th of 85 in raw time, right behind an ASP Cayman with Hoosiers. 7th in index time, behind two national trophy winners, but ahead of a 5-time national winner. For proper SCCA competition I assume people would put 19" wheels with RE-71Rs on, rather than a completely stock car. I still think there is a lot of time to be gained from my driving better (this is always true, but I mean 0.5s or more).
Very nice!
I will have to buy a new gauge.
Michelins.
I didn't have my temp gauge with me so annoyingly I had to borrow one a few times so I wasn't able to check as often as I would've liked. Last I remember I was at 29, 31-range in between my runs.
During the second set of sessions (runs 4-8) the ambient temp rose a bit and that's when I set my suspension/ESC settings which made so much difference, so I'm not sure exactly what made the biggest change. No more understeer, and my times were 3-4 secs faster and very consistent. I know if I had a few more runs I would've easily been 2+ secs faster.
All buttons on (sport, PASM, exhaust, TSC+ESC off). Front swaybar middle, rear swaybar hard, which will definitely affect the balance.
It wouldn't surprise me if tire gauges weren't well calibrated especially if old (mine is ~12 years old). They should be consistent so you can find the setting for your gauge that works for you, then replicate it.
My last 4 runs (3rd to 6th) were all within .3s so pretty consistent. I'm driving one corner behind where I used to, which has a definite time impact (entering a turn I'm mentally setting up for the next corner, where I should be thinking about the one ahead of that). For me it takes a lot of constant seat time to get there, and I don't think I can spend that many weekends on it. I'm pretty happy so far both with the feeling of the car and the results.
I found 30lb front/33 lb rear hot pressures worked well with SC2s on a 70 second course in 60* weather with stock alignment, front bar in the middle, rear bar full stiff, console all lit up.
Required some patience with throttle to avoid understeer and rear end was difficult to rotate. May increase rear pressures a bit next time, and should have alignment dialed in to help with turn in.
First run on cold tires and wet cold surface was very entertaining but this car is very forgiving and responsive to corrections.
Second weekend out, still running 30/30 hot F/R on the Dunlops, no passengers this time, FTD overall although the field was small. Still, though, always an achievement when you can beat Hoosiers. There was a guy in a very well set up BRZ on RE-71Rs that was giving me fits. They might be my next set of tires if I can make these Dunlops last all summer. Doubtful, although the wear looks ok right now. We'll see how this weekend's event goes, then an HPDE on Memorial Day weekend.
Did my first autocross of the season yesterday with PCA Potomac, with a total of about 60 participants. Very soggy, pretty much rained or drizzled all day. Car had fairly-new Michelin SuperSport tires, ran with pretty much stock pressures -- 29F and 33R. Ended up taking FTD on my last run, and with a passenger! A few of the other folks accused me of running "cheater" treaded tires , since they were running on R-comps.
Did my first autocross of the season yesterday with PCA Potomac, with a total of about 60 participants. Very soggy, pretty much rained or drizzled all day. Car had fairly-new Michelin SuperSport tires, ran with pretty much stock pressures -- 29F and 33R. Ended up taking FTD on my last run, and with a passenger! A few of the other folks accused me of running "cheater" treaded tires , since they were running on R-comps.
I was going to go to this but the lousy weather killed my motivation over the weekend and I slept in . Hopefully I'll see you at a future PCA Potomac event.
Are you guys running in SS? I ran this weekend with the Pan Am SCCA group and was in SS. It was a two day event but I only raced on Sat due to mothers day. Got 1st in my class on Sat. Was faster than second place by 2/10 and faster than third by over a second.
My buddy who ran both days told me that on Sunday, they penalized me for running the MPSC2 and adjusted my times, took away first and gave it to the guy who was 2nd. I ended up in 3rd, so I know the penalty was over a second. Not sure on the actual deduction though.
I have raced road course stuff mostly but am pretty new to autox. Seems that in the rules section, it says in 13-C-1 that it is ok to run OE spec tires at regional events.
Do I have any recourse? Or was I in the wrong? I was not there to explain that they are OEM tires on sunday. I am more concerned that this relatively small group will think the new guy is trying to cheat; more so than I am concerned about retaining 1st.
Is there anything I should reference other than 13-C-1 to plead my case?
Only the first three chapters of the scca rulebook are mandatory for local events. Regions can run whatever classing rules suit their needs. Our region has mandated the 200 treadwear rating for all S and ST classes.
In my club I run in SSR because I have (well, _had_) the Dunlops which are 80 tread wear. I'm sure even the Cup 2s would be SSR though because they are 180 tread wear. I don't personally care that much any more; I'm chasing FTD now.
The Dunlops are good tires, but I already shot the fronts to heck. I'm going to try the Cup 2s next; hopefully I can make them last until the Hoosierstones are available in our sizes. Fronts already are, just waiting on rears in a 295.
Yeah, they put me as SSR as well. Basically no way to be competitive at SSR with mpcs2 tires. It gives the stingray vettes out there more than 2 seconds on me. I'm ordering 19" re71r tires for the tread wear and to be able to run 19's and help with the gearing. I have a set of wheels just sitting in my garage anyway.
Another question though, are you guys that are in SS, running tarrett or rss toe links for more camber, or just maxing out oem?
04-19-2016, 08:58 AM
A few of the other folks accused me of running "cheater" treaded tires 
, since they were running on R-comps.
. Hopefully I'll see you at a future PCA Potomac event.
