donsun

if you want to be that competitive as to look into pax index, I'm pretty sure you'll get the best 'pax index time' staying in H-stock and getting r-comp tires.

MightyP

iTrader: (1)

While I agree with you (HS PAX is .791), it would mean not only could I not upgrade my car anymore, but de-modding it (intake, short shifter, springs & motor mount). I want to be as competitive as possible, but still be able to play with my car. ST was good except for tire width (with so much room in the wheel wells, seemed silly to stay on 225 tires), giving me plenty to play with (springs, sways, tower braces, intake, exhaust, header, short shifter, etc).

Bottom line, I bought the car specifically so I could tinker with it, so stock is out, leaving me in at least Street Tuning. Then it just became a matter of finding my happy place where I can play and still be competitive. Right now, I'm not competitive in my car. My PAX score placed me 20 of 29 and when I let guys who are consistently top 5 in PAX do a run in my car, they were slower than I was. Given they don't know my car and I do, I'm sure they'd pick up time if they did a few laps, but it gives me a good idea that my lack of skill is only part of the problem.

UPDATE: Clearly I'm learning as I go along... BBK and LSD in fact are allowed in STX. Definitely the right class for me.

2tCornot2tC

Do not adjust your tire pressures based on how the tires seem to be wearing for you. Looks are very deceiving! Only adjust your tire pressure based on how the car feels/performs. You are also making monstrous tire pressure changes going from 40 – 46. You are going from one extreme to the next. There is no way of knowing what you have done to the handling that way. You should only make no more than 1-PSI change at a time. Once you get it into the ball park, you will find yourself only making 0.2-PSI changes…trust me on that one.

2tCornot2tC

I got this tire inflator and took it to work to calibrate it. This gauge is accurate to 0.01-PSI! And it reads to 0.1-PSI accuracy. For only $70, this is a must tool.

http://www.amazon.com/Astro-Pneumatic-3018-Digital-Inflator/dp/B002PUTC0M/ref=sr_1_8?ie=UTF8&qid=1313491139&sr=8-8" target="_blank">http://www.amazon.com/Astro-Pneumatic-3018-Digital-Inflator/dp/B002PUTC0M/ref=sr_1_8?ie=UTF8&qid=1313491139&sr=8-8

http://www.amazon.com/Astro-Pneumatic-3018-Digital-Inflator/dp/B002PUTC0M/ref=sr_1_8?ie=UTF8&qid=1313491139&sr=8-8">http://www.amazon.com/Astro-Pneumatic-3018-Digital-Inflator/dp/B002PUTC0M/ref=sr_1_8?ie=UTF8&qid=1313491139&sr=8-8" /> http://www.amazon.com/Astro-Pneumatic-3018-Digital-Inflator/dp/B002PUTC0M/ref=sr_1_8?ie=UTF8&qid=1313491139&sr=8-8">http://www.amazon.com/Astro-Pneumatic-3018-Digital-Inflator/dp/B002PUTC0M/ref=sr_1_8?ie=UTF8&qid=1313491139&sr=8-8

For some reason this link is going nuts...

MightyP

iTrader: (1)

Good info on the tire gauge.

And I understand what you're saying about minor changes, but remember, I'm at the very amateur side of racing and what you're suggesting has some practical problems for me.

1. The courses are different for every event, so I only get 8 laps to learn the course and make adjustments. A more experienced driver can walk a course and go full out the first time through, I'm not that experienced yet.
2. I haven't taken the time to verify this, but I'm guessing my tire pressure changes by at least 1 PSI during the lap. My tires go from warm to the touch to too hot to touch after only 1 lap. How do I determine the ideal pressure?
3. I have 4 laps in quick succession, a break and 4 more laps. I can only realistically change my tire pressure once during an event. At 2 events a month, by the time I start to zero in on the ideal tire pressure, that ideal will change due to weather changes.

Bottom line, I agree that your way is the better way, but I don't think I can reasonably apply it with my current skills and abilities. 35 PSI up front felt sloppy the first time. This last time, 46 PSI didn't feel as sloppy, but didn't dig in as well. In both cases, the tires felt sloppy and in both cases, the tires didn't grip as well as I hoped, so now I'm splitting the difference to try and get the best out of my tires.

Thanks again for the info

2tCornot2tC

Quote:

Originally Posted by MightyP

And I understand what you're saying about minor changes, but remember, I'm at the very amateur side of racing and what you're suggesting has some practical problems for me.

You are selling yourself short…that is just an excuse. Experience only gives you the fines not to repeat your mistakes.

Quote:

Originally Posted by MightyP

1. The courses are different for every event, so I only get 8 laps to learn the course and make adjustments. A more experienced driver can walk a course and go full out the first time through, I'm not that experienced yet.

Not true! You think way too highly of an “experienced” driver. Walking the course is only to look for imperfections in the road that will get you into trouble…or to look for features to help you go faster than the others. With time you will learn what to look for.

Quote:

Originally Posted by MightyP

2. I haven't taken the time to verify this, but I'm guessing my tire pressure changes by at least 1 PSI during the lap. My tires go from warm to the touch to too hot to touch after only 1 lap. How do I determine the ideal pressure?

Yes…physics 101…with temperature, the pressure will rise…and very linearly! The trick is to do the same think every time. Know what your cold pressure is – then keep an air temperature log and if possible a track temperature log too. That way, when you get to the track, you get the air temperature and the track temperature to select your tire pressures. You are ready to go when you get there!

All the “experienced” drive knows is his staring points and therefore only spends his time dialing in his settings and doesn’t have to start from scratch every time he shows up at the track.

Quote:

Originally Posted by MightyP

3. I have 4 laps in quick succession, a break and 4 more laps. I can only realistically change my tire pressure once during an event. At 2 events a month, by the time I start to zero in on the ideal tire pressure, that ideal will change due to weather changes.

See above comment…and tire pressure is NOT the cure all. This is just the cheapest and first thing to learn while racing. Keep a very good log.

Quote:

Originally Posted by MightyP

Bottom line, I agree that your way is the better way, but I don't think I can reasonably apply it with my current skills and abilities. 35 PSI up front felt sloppy the first time. This last time, 46 PSI didn't feel as sloppy, but didn't dig in as well. In both cases, the tires felt sloppy and in both cases, the tires didn't grip as well as I hoped, so now I'm splitting the difference to try and get the best out of my tires.

Good! You are learning your car…once you get to the point that tire pressure will not get you the performance change you need, time to try something different – sway bars, springs, chassis bracing, etc.

MightyP

iTrader: (1)

LOL, fair enough. And I really am trying to learn.

1stOne

Number one thing to do. Fix the nut behind the wheel. The rest will come from seat time and talking to other guys. What works for some, doesn't work for others, remember that.

Use the car, use the track. Smooth is fast!

MightyP

iTrader: (1)

Is anyone besides 1stOne and me actually AutoXing? I'd love to hear how the car is doing for you! And I might have an offer.

donsun

I've done 5 autocross events and 2 HDPE's so far on a stock car except exhaust/intake. Tire pressures are the only 'setting up' i've done so far