I just started wrenching on a local 358 sprint car team and learning the ropes. They were a top five team last year with a couple wins under their belts.
One of the things I noticed is alot of scattered notes. Im helping the guys use excel to come up and organize alot of different information.
Right now Im working on a gearing chart/dyno chart crossreference.
One variable i need to come up with is how many inchs the car travels per revolution of the rear axle.
Would be super simple with a non-staggered rear tire... but how do you do it with a staggered rear car?
Say we are running a 94" lr tire and a 104" rr tire... how would you calculate the MPH?
I would guess the distance per revolution (tire that is) would be (94+104)/2 = 99 in/rev.
But then I thought about how the car loads the right rear super heavy and thought the car might be driven more by its larger diameter...
So then i though of something like this, as simple expression that trys to take this in effect... x1(rr tire)=104 x2(lr tire)=94 y=(x1-x2)*.75 ... then rev/min would = x2+y == 101.5 in/rev.
There is no way to be super accurate with this, but im just trying to come up with a baseline. A 3" jump in rr tire diameter is not uncommon from the heat to the feature so I want to be able to see how much its going to affect our gear...
"Buying parts I dont need, with money that I dont have, to impress people that I dont know".