do big wheels afect HP numbers on a dyno like 18's they are the C6 wheels

 

Not enough to really make a difference. Depends on the dyno too, if you use a Dynapak it won't matter what wheels you have lol

 

Their is a dummy here with 20's on his TA, Good set up ms3 ,heads, fast 90 and stall but real shitty. The car made 380ish on the dyno,But on the street is mega SLOW!.

 

I wondered if my 18s made my numbers lower as well

 

I dont think so. I think F bodys do fine with 18/10 inch tires. I have light weight aza rims on mine 18.9.5 all they way around, and from the american racing rebals rims I had my car, It drop 170 lbs when I went to the aza rims.

 

I have done tests or helped with tests on 17", 18" and 19" wheels.

Plus we looked at differnt wts of tire and wheel combinations.

First 17" 18" were very close to the same power output. but 19" were down by 10-12 HP. One of the big challenges of this test was we could not find light wt 19" wheel tire combos.

Most of our 17" or 18" tire wheel combos were 40 lbs +/- 2 lbs. When we put on 17" or 18" wheel tire combo at 50-55 Lbs or more the HP dropped like a lead balloon. as 7-9 hp decrease.

The 19" combo use was 57 lbs per wheel.

The other factor is where is the wt located? the farther the wt is away from the center of rotation the slow the wheel, or more energy it will take to get that wheel rotating or slowed down.


any time one can reduce wt the faster the car will go. Reducing the unsprung wt of the wheels is best of all. Each pound reduced off the wheels is almost as much of a power increase as removing 6 1/2 pounds out of the car.

So yes reduce that rotating weight and wheel diameter and go faster.

My road race rear wheel 18x13 CCW Classic Track with GY G19 ( 25.5x11.5x18 )or Hoosier A6 335/30x18 = 39 lbs



My street rear wheel 18x12 CCW classic street with Mich PS 335/30x18 = 51 lbs

 

Golden Eagle is exactly right, it's the weight that matters most since most folks aren't changing the overall tire height too much. Where the weight is matters also, as mentioned. Unsprung weight and rotating mass are major factors in drivetrain and suspension performance. Wheels/tires are BOTH so you get an additive effect.

 

How much more rwhp would my 16" salad shooters with 245/50 nitto DR's net over the 17x11 ZR1s with 315/35 goodyear supercar f1's do you think?