Tire Pressure At The Track?

I just went from running 17X9.5 ZO6 Motorsport rims to 15X10 rear and 15X4 front ProStars. I was able to shed about 100lbs in rotating mass. So, I can't wait to see what new times I get. I ran a best of 11.98 last year.

Anyway, with my old setup I ran 275/40/17's MT ET Street Radials and lowered the pressure to about 20lbs at the track. This worked pretty well for me. Now I am running 275/50/15 MT ET Street Radials. I was told I should not have to drop the pressure as much because of the taller sidewall of the new rear tires. It was suggested that I start around 28lbs and work my way down from there. I figure dropping 2lbs at a time would work best.

So, who runs a similar setup and what do you find works well for hooking tire pressure wise? The car makes about 436RWHP and 410RWTQ on a dyno jet.

Oh yea, any ideas on what I can expect for improvments in my times going from what I had to the new setup? I was hoping to see .20 better times?

Thanks in advance for your help!

Bill

I'm running the same size Hoosier DR and found that 22psi works very well.

100 lbs of rotating mass will have the same effect as 300-400 lbs of static weight. When I went skinnie fronts I lost 34 lbs and a solid 1 tenth in et.
So I would say 3 tenths and 3 mph. But remember the weather is horrible for drag racing right now and the gains might be swallowed up by the heat.

I'm running the same size Hoosier DR and found that 22psi works very well.

100 lbs of rotating mass will have the same effect as 300-400 lbs of static weight. When I went skinnie fronts I lost 34 lbs and a solid 1 tenth in et.
So I would say 3 tenths and 3 mph. But remember the weather is horrible for drag racing right now and the gains might be swallowed up by the heat.


Thanks Al,

I also got all of that audio/video equipment out of the car and removed the rear seats. This allowed me to drop another 100lbs. So, I dropped about 100lbs off the rims and tires and another 100lbs off with removing the audio/video equipment and seats. I am looking for another 50lbs to drop in ASAP. My goal was 300lbs but will settle for 250.

I saw your post about Stanton. If I had a truck and trailer I would head up there in a heartbeat. I am just affraid of breaking down 100 miles from home. I'll probably head to Milan next Wednesday and get there when the gates open. This should give me 4-5 good passes before it gets busy.

Thanks,

Bill