I have never actually experimented with this ... but with the car I am working on now I will.

I say it depends on what your race-car-combo is. Some might need to run 165 psi ... but with a car that does not weigh much, has better aero than a big-car and does not have a ton of horsepower ..... I think you can run A LOT less.

PLUS ... running not-more-than-you-need line-pressure is EZier on the metal and rubber seals AND it would take less power to run way higher than necessary PSI.

My combo will be a front-motored dragster ... that all I hope it will do is be a mid-9 second "fun car" .....zero maintenence .... "change the oil once a year".

I am going to set my trans at 80 psi or so.