Will dyno results vary based on the size of the wheels and tires on a car?
I assume so as everyone wants light weight 18" volk racing wheels for speed and 19" or 20" for show. What can you tell me?

 

Yes. Everything along the drive train effects rear wheel horsepower. The relationship between wheel weight and power is simple: it takes more power to turn a 25 pound wheel than it does a 20 pound wheel.


Of course there is a dyno that takes the wheel out or the equation.

 

I did exactly this test with 3 sets of wheels and tires.

1) Stock wheels and tires = baseline dyno results
2) 17" Light weight Enkis with Toyo RA1 race tires = ~ +7HP across the whole power curve. (as an average, this is a big increase)
3) 21" Big bling chrome heavy wheels with street tires = ~ -14.5HP through much of the curve.

So...
Smaller/lighter = quantifiably more power.

 

That's what I thought. So basically anyone can fudge their dyno numbers a little bit by switching wheels for the test. I may be going from chrome Nissan wheels to volks to pick up some additional whp.
Does anyone have numbers to post on volks?

 

Most people don't bother doing before/after dynos after a wheel change. It's more for looks and it's pretty much a "given" that lighter wheels/tires will give a little performance bump. Keep in mind that wider tires have more rolling resistance so that hurts performance a little, but you do gain traction.

 

I am buying new front tires for my 03 z (18") which ones should I get?

 

The difference in changing wheel weight will be negligible. On the order of less than 1.5%. Hell most the dyno's out there aren't that repeatable. So unless you're doing a shootout or trying to break x99ph and are trying to get to x00.

As for the dynapack..

 

We will ignore this question so you do not get hammerd.Search my newb friend.

 

Browse the Wheels/Tires forum:
https://my350z.com/forum/wheels-and-tires-60/

The question has been asked and answered hundreds of times.
The simplest answer is to get more of what's already on there unless you're unhappy with them, right?