Alright well we all know less rotating mass is going to make more power on your car. Lighter wheels, aluminum driveshaft, etc will all help free up some HP/TQ.

But how much? I know going from a stock steel to aluminum free's up 1-2 HP and afew 3-5 TQ. How much do you gain going to lighter drag rims compared to heavy ZR1's or something.

I ask because I recently went from 17x9 SS rims to 17x9.5 and 17x11 TT 2's. Wider heavier rims, meatier heavier tires. Honestly the car does seem to have lost a bit of power and I kinda wanna know how much. Are there any kind of formula's or estimates? Just wondering.

-Dustin-

 

I have seen a calculator to figure this up by component,but can't remember where.
The total weight of the car when it is "hooked" will determine how fast the engine accelerates. If ya are running a 4,000lb car ya can't expect high dollar internals to "magically" let the engine rev any faster than the weight it is pulling.
If ya had a 2500lb car that would be different.
IMO most of the light weight stuff in a heavy car is money down the toilet.
HP will accelerate it quicker than light stuff(with traction)
Not to say light stuff doesn't have it's place,but IMO it isn't a cost effective return on investment. In our type of street/strip cars I can't see it.

 

Well I'm mainly speaking of rims/tires and driveshaft. Internals are thousands away from where I am. I just was wondering how much I might be losing.

-Dustin-

 

The problem is not the 4th gear dyno pulls but the lower gear dyno pulls that are at higher accel rates, thats where you find the gains.

That's why I pay attention to crankshaft inertia.

Bret

 

IMO ya ain't loosing enough to worry about.
Ya can look at tires and wheels like a flywheel.heavy is hard to start and stop,but once started the take less to keep going.
We have tried it with different wheels,same tires = no change in ET or MPH.We have tried taking metal off of the ring and pinion,drive shaft,gun drilled axles with scollop's = no major change that was consistent that ya could say the lighter mass did it.
Taking weight off of the whole car either sprung or unsprung and building HP makes the most change in ET & MPH.

 

Alright, so hopefully its just my imagination. It'll go on a diet in the spring. Thanks.

-Dustin-