SCCA Solo C Street Discussion

[jprice130]

Originally Posted by Kido1986

That happened to us! Kosei's with 2 metal valve stems per wheel. Ripped it clean out at a local event. All 8 changed immediately to rubber.

Wow! Nice! I knocked over my fair share of cones with those Koseis (Jadrice too), but I can't say we ever ripped or broke the valve stems. Way to get after it! lol!

My new STX wheels have rubber valve stems as well. Glad I went this route....

[Rexpelagi]

Originally Posted by FastWhite

Ok enlighten me. Old man remember. Where did I put my foot this time?


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Haha it is probably more the way you said it than what you are actually doing. When you lift off the throttle you shift weight to the front of the car, which unloads the rear and tends to induce more oversteer.

If you are in a corner and the rear starts to slide you actually should add partial throttle to transfer weight to the back and settle the rear of the car.

If you are accelerating and the rear starts to slide, you want to back off the throttle slightly but generally not all the way, as a quick throttle lift will have the same effect as above and unload the rear too quickly.

I'm thinking you meant under acceleration, but since you didn't specify I gave you a silly O.o face. :-). A good way to think of it is that the gas pedal and brake pedal are weight transfer devices, at least when it comes to balance. It is the same logic with why trail braking into a corner aids turn-in - a little extra grip where you need it and less where you don't.

[ViperASR]

Video and SoloStorm Data from the Dixie National Tour this weekend:
[ame="http://www.youtube.com/watch?v=EmgXBHwawgs"]2014 Dixie National Tour - C-Street BRZ #99 - YouTube[/ame]



Huge thanks again to Henry for letting me run the car. These cars are way too much fun in C-Street. Ran out of gear a few times, but nothing that would want to make me put a taller tire on the car. Even with a few big acceleration zones, I never felt the car needing more power, I was able to be pretty agressive with the throttle at or before apex. With it being a Strano course, there was a lot of slow in, fast out.

It was nice meeting a few of you FT86 guys. Deff a good group of people.

Car setup is typical C-Street. I really like the Z2s after this weekend, and have a set sitting in the garage for my STR car.

[Rexpelagi]

Originally Posted by Rexpelagi

Nope, I don't have any dB data. I haven't actually run my car anywhere that has sound monitoring as I got it at the end of the season last year and drove John's car at Nationals.

I should add to this. Andrew Pallotta used the same delete (Nameless) in STX until he got his full exhaust, and he never had an issue with sound. I know he ran several national events with that setup, so you should be ok.

[FastWhite]

Originally Posted by Rexpelagi

Haha it is probably more the way you said it than what you are actually doing. When you lift off the throttle you shift weight to the front of the car, which unloads the rear and tends to induce more oversteer.



If you are in a corner and the rear starts to slide you actually should add partial throttle to transfer weight to the back and settle the rear of the car.



If you are accelerating and the rear starts to slide, you want to back off the throttle slightly but generally not all the way, as a quick throttle lift will have the same effect as above and unload the rear too quickly.



I'm thinking you meant under acceleration, but since you didn't specify I gave you a silly O.o face. :-). A good way to think of it is that the gas pedal and brake pedal are weight transfer devices, at least when it comes to balance. It is the same logic with why trail braking into a corner aids turn-in - a little extra grip where you need it and less where you don't.

I see your point. After driving for over 40 years, I do so much by instinct that I almost can't explain what I do. Your explanation is so much more eloquent that I take my hat off to you sir.
YA what he said.



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[JB86'd]

Some really great info in this thread, especially for an autocross noob like me.

I'm going to be doing my first autocross this Sunday..should be about 70 degreesF out.
I'll be running the stock Michelins and stock alignment settings. With very little or no camber are the shoulders of the stock tires going to be done for after a day of autocross?
Also, would bringing a water sprayer to cool the tires inbetween runs help me a lot?

[7thgear]

you'd need to try really really really hard to kill the stock tires in a single day

i would just add extra air and save the water for yourself.

[Sccabrz192]

I've run 4 events on the stock tires:
8 runs (2 drivers @ 4 runs)
12 runs (3 drivers @ 4 runs)
8 runs (2 drivers @ 4 runs)
8 runs (2 d @ 4 r)

for 36 runs on the stock michelins and also have about 20k road miles on them and still have 7/32's tread depth. they are pretty resilient.

[JB86'd]

Originally Posted by Sccabrz192

I've run 4 events on the stock tires:
8 runs (2 drivers @ 4 runs)
12 runs (3 drivers @ 4 runs)
8 runs (2 drivers @ 4 runs)
8 runs (2 d @ 4 r)

for 36 runs on the stock michelins and also have about 20k road miles on them and still have 7/32's tread depth. they are pretty resilient.

Wow that's pretty amazing. What kind of camber are you running? Also what PSI do you run cold?

[Kido1986]

I'd pump them up for ~40psi. Keep check on them, lower down to 40 after each run.

High PSI means less roll over, less wear.

[Sccabrz192]

Originally Posted by JB86'd

Wow that's pretty amazing. What kind of camber are you running? Also what PSI do you run cold?

I was in the 35-36 psi range rear and 37-38 front. I set the pressures then bleed them off as they reach temp, so I use those pressures regardless whether they are cold/warm/hot. Camber wise I have been using the OE crash bolts since event #1... so ~1 degree.

I should also note this lot is asphalt and a bit gravely so it's pretty friendly on tires compared to some of the cheese grater concrete surfaces.

This year I'll be on ZII's, so I won't be running the OE's any more.

[DylanFRS]

Originally Posted by Kido1986

That happened to us! Kosei's with 2 metal valve stems per wheel. Ripped it clean out at a local event. All 8 changed immediately to rubber.

Ugh, i just got my Koseis w/ tires mounted from Tirerack with those stupid stems in them. I really don't like the metal valve stems because I have more troubles quickly checking pressures with them too.

[zohaib]

Thank you sir for making this as simple as possible.

[Wepeel]

Originally Posted by ViperASR

Video and SoloStorm Data from the Dixie National Tour this weekend:

Very nice - looks like you're really driving on the limit and were driving with a lot of confidence. Congrats on the win!