Hi Paul,
A top ten finish is great, almost making the top five is fantastic.
Our Type 1 VW's are way down on power compared to most of the competition. But you just showed everyone a Type 1 win is possible.
I havn't run the "new" PBIR, but used to run it back in the 1970's when it was plain old "West Palm Beach."
I am curious about your gaining 10psi on hot tires, and don't need a specific answer, but just asking a couple of questions that you can compare to your own car's experience. If we gained more than 4psi on our cars, it was out of the ordinary. We expected about a 4psi gain, even on both sides of an axle. Fronts and rears don't normally go up the same amount, but the end working the hardest goes up the most. For me, 6psi was getting up there -- and I'm talking Road Atlanta in August.
Different tires run different temps, of course, but we typically use 26-front 28-rear as a starting point, and depending on results, adjust from there.
FJC
24-Hour ChumpCar race at PBIR THIS SATURDAY!
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FJCamper
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vdubsinjensen
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Re: 24-Hour ChumpCar race at PBIR THIS SATURDAY!
http://youtu.be/JJSefSlwEEU
We also started out at 26psi in all four tires. It got pretty slick fast.
We also started out at 26psi in all four tires. It got pretty slick fast.
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FJCamper
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Re: 24-Hour ChumpCar race at PBIR THIS SATURDAY!
Hi Paul,
With you starting at 26psi, and gaining to 36psi, all under "normal" racing conditions, your tires are the tell-tale witnesses to improved power and stiffened suspension.
I'm guessing that at 36psi the tire pressures were too high and your tires were "skating" across the track, with little sidewall flex.
My first response would have been to drop the pressures so that the hot tire pressures were 26 to 30psi, which would of course have been too low when cold.
Something to check for -- a small amount of water in your tires from the air source, which increases hot pressures as the water vaporizes. When I can, I use "dry air" to fill my tanks (one or more driers on the air line). Nitrogen would fix this as well, but you first have to dry out the inside of the tire to make it the most effective.
FJC
With you starting at 26psi, and gaining to 36psi, all under "normal" racing conditions, your tires are the tell-tale witnesses to improved power and stiffened suspension.
I'm guessing that at 36psi the tire pressures were too high and your tires were "skating" across the track, with little sidewall flex.
My first response would have been to drop the pressures so that the hot tire pressures were 26 to 30psi, which would of course have been too low when cold.
Something to check for -- a small amount of water in your tires from the air source, which increases hot pressures as the water vaporizes. When I can, I use "dry air" to fill my tanks (one or more driers on the air line). Nitrogen would fix this as well, but you first have to dry out the inside of the tire to make it the most effective.
FJC