I was just wondering, if i were to dyno my car with some 20lbs 17" wheels on 205/40 tires... would there be any HP difference if i changed to some 14lbs 16" wheels on 205/45 tires? Would the lighter weight and less rotating mass give me more power?

 

yes wheel weight and size, will effect the power, as you know, it is easier to rotate something that is light also, it depends on where the weight ...closer to the center the less effect on the power...

 

Try using some 155/80/13's at 50 psi when you dyno to "inflate" your numbers.

Best to always use one set of wheel/tires/psi for consistant numbers.

I have a old set of steelies with 175/70/13's on them. I used 40 psi when I did my dynoing 2+ years ago.


[Modified by Mista Bone, 5:18 AM 12/23/2001]

 

Yeah you'll have more HP with those wheels but once you put your heavy *** 17s back on your gonna loose it. See if they can Dyno your car a 4th time with your 17s on and you see at least a 6 to 12Hp drop. You'd need to weigh you rim and tire combo to get a true picture of what you dropping in rotational mass. But it's gonna be alot.

 

thanks for all the input. also, how much hp do you think a bypass valve robs from the cold air intake? thanks.