And right next to the poor man's way you described, is the correct way as shown in the 2008 Michelin Race Tire Catalog. Add to this, An Introduction to Race Car Engineering Book 1 (a road racer's bible) spends about 200 pages on tires to develop an understanding of what they do, why they do, and how they do along with detailed photos to help learn to identify the myriad things you can do wrong to cause issues with tires and prevent yourself from maintaining maximum grip. And we haven't even started to talk about anything else - springs, shocks, suspension geometry, swaybars, corner weights, etc., etc., etc..

So, I say one thing - none of us are here to find ultimate speed with our cars. If we were, we probably wouldn't have bought this car in the first place, but just for S&Gs, lets say we did. You'd need to scrap most of the suspension bits from the factory and replace them with adjustable pieces to remove the designed in understeer and get the car balanced. You'd need to replace all the suspension rubber bushings with solid rod end ball joints so your alignment isn't +/-5% all the time. You'd need to measure your chassis and model the suspension to understand what ride height works best and what things you can and should modify to dial out the rest of the factory designed understeer. Then you'd need to test, test, test, and more test to find what settings give your tires the most contact with the pavement under the widest range of conditions while making sure we are going fast enough to get the tire compound into the happy range of temperature across the entire width of the tire.

No one posting here is doing all this. It's too time consuming and too expensive unless you are actually competing. As far as I can see from the races I have attended, the IS cars don't show up. There isn't enough support to help with all the stuff in the paragraph above. If you own a BMW, all this stuff has been done and help is available at all levels to make it happen. Lexus still isn't there, and doesn't appear to want to be there at the grassroots level. The RC F GT3 car is a start, but it's going to take a long time to get to where BMW is in SCCA local and regional competition.

I grew up with 1/4 mile and 1/2 mile dirt track racing all over the Midwest, both locally and USAC. Years ago, I worked with a mini-sprint team and helped with engine and chassis tuning. I learned a LOT very fast.

Most importantly, I learned two incontrovertible truths from racing. 1. If you want to make a small fortune in racing, start with a large one. 2. Racing with any intent of winning takes all your time and all your money. It's hard work when you want to win.

 

 

If you are using whole air, those numbers are pretty typical. If you use dry nitrogen, you look for 1 - 2 psi max.

 

 

Right, but it isn't nitrogen that's the problem, it's water vapor. Your humidity will impact pressure rise dramatically. BTDT got the t-shirt. It's really hard to remove all the water from compressed air despite it coalescing in your storage tank. It's really easy to drop some volume of pure liquid nitrogen into an evacuated cylinder and get (effectively) no water at all. If you did the same thing with whole air, your results would be indistinguishable from dry nitrogen.

I spent a lot of time in the cryogenic gas world, and in my last job in the Air Force, managed operations for a lab using about 7 tons of liquid nitrogen weekly. I'm pretty familiar with a wide range of things you can do with it - not the least of which is have one of your troops liquefy methane and jeopardize the safety of an entire 10,000 square foot building.

FWIW, here in the US on a typical summer day, starting at 32 psi cold with street tires nets between 42 and 44 psi hot. It works just fine on these cars on our tracks in the Southeast.

 

#3 > speed costs money, how fast do you want to go?

 

#4 To finish first, you must first finish.
#5 When the green flag drops, the BS stops.