vwdave

This can be related to thirdgens. I know I will use the information when I put slicks on mine in the coming months.

I personally have no experience with using slicks. A buddy of mine has a 91 VW with a 1.8t big turbo running about 320whp in a 2000lb car. We mounted some 22x8x15" Et Drags on it.

We wet down the floor in front of a friend's shop and we ummmm....."break in" the tires. First thing I notice is in the marks, the outsides are very dark and there is no marks in the middle. This was at 12psi tire pressure. I told him to bump it to 14 and it grabbed better. But thats all the time we had for the day.

Anyways. What is the best way to determine what tire pressure to run? Im thinking maybe the tires are still too low and should be bumped to 17-18psi. Would that even things out and make the car grab harder?

jbenge

iTrader: (2)

Trial and error is the best method to find the tire pressure you need. I like to start a little high and work my way down. Theres a breakover point where you don't gain any more traction(60' time) and start to lose mph. I've had the most success running my ET streets at 15-16psi. I run tubes with mine since I do some street driving with them and I think the tubes also have an effect on optimum pressure.

IHI

iTrader: (1)

You can do the burnout method until the cows come home, it's going to take real world changes per run to find the optimum psi you'll need. Start high and come down. Mine at 14psi will blow the tires off and create very violent tire shake, 10psi is where everything is happy. Max traction for good 60's, good finish line stability, and most importantly, being able to keep the light green...going to 10.5psi and I'm red lighting.

As for tubes, not necessary unless your running M/T since the saidewalls are sooo thin they literally bleed air out. Tubes add alot of weight to the tire and will slow you down. I tried 2 sets of tires with tubes and will never go back to them, not needed, slow you down, so I see no advantage to running them...EXCEPT they do help keep psi the same between rounds alot closer. Mine tubless I come back at least 1-2psi higher than what I set them at in staging lanes, by the time the next round is called I'm either a psi high/lower than my staging psi...alot depends on where or not the sun is shining on your tire between rounds...shadey and the tire will lose psi...sunny the tire will gain psi...running tubes the fluctuations are alot less noticable.

5678TA

i ran 26x8.5 slicks this past weekend and my first run at 14psi, hooked pretty damn good for a first run then got really squirmish by mid track.. put it to 18psi and hooked the same and better later on and was much more stable at the topend.. like jbenge said, trial and error..

AlkyIROC

What everyone just said. Start high and work your way down until 60' times stop improving. Go 1/2 pound at a time.

My tires are poor examples. My 32x14 stiff sidewall slicks with no tubes have 9 psi in them. I don't have enough track time to say if I need more or less. Based on my 60' times compared to last year when I had smaller tires, I'd say some improvement can still be made with tire pressure.

Doing a burnout on a wet floor can get you in the ballpark. You want that even contact patch across the tread. Same goes for finding best tire pressure in a street tire.