Auto Racing: Race tire pressures and Motor Oil, inflated tires, air expansion

Question
For racing:

What rating of motor oil is best? Stick to the recommended
rating or can I deviate from it in order to boost a bit of
performance from it? Any drawbacks?

Will pumping the tires to the recommended air pressure rating
Ok for the tires for racing? I am worried of heat expansion, but
at the same time, lose the handling if it's under-inflated.

Thanks for helping;you have been amazing!

Answer
as for oil: try using some fully synthetic oil (Mobil1 or so) those oils preserve the engine and allow it to give its best.

no major power gains can be achived from different oil brands, they will just vary in how well they will protect your engine and you need the best protection under harsh racing conditions.

i personally use Mobil 1 even though i don't race but still i need the protection.

as for tires pressure: the recommended tires pressure by the car manufacturer is for absolute comfort... the car can do with higher pressure but the ride will be stiffer.

the trick is to keep the pressure higher than the car manufacturer recommendation but less than the max pressure the tire can handle.

so if the car manufacturer recommended 32 psi and the tire max pressure is 44 psi (you can find that on the side wall of the tire) then beeing at some 40 psi will give you the best results.

as for air expansion and all: all tire pressure readings are done when tires are cold so you inflate\adjust your pressure when tires are cold, if they are hot then you will have wrong readings from expanded air.

pressure is said to increase 2 psi between a cold tire and hot tire... in hte previous example i gave a 4 psi caution for air expansion just to be safe knowing that those extra 4 psi will not add that much stiffness to the car handling.

just remeber to put back the correct pressure when you are done racing... over inflated tires will wear faster than correcly inflated tires.

needless to say that under inflated tires will ruin your handling and cause the car to be less pointey.

however low pressure tires adds to the tire grip so you deflate some of your tires presseure if you are stuck in mud or sand to help the car get out of the mess.

thanks for the complement man!

MMamdouh