Would my dyno numbers be affected by the following?

[Litespeeds]

Hello fellas,
Had my 92 NSX dyno'd on Saturday and here is a link to my results. Please analyze for me.
http://www.nsxprime.com/ubb/Forum8/HTML/000205.html

What I need to know is if the following will have any influence to the numbers that I received in either horsepower or torque?

1) 18x10" wheels with 275/35/18 tires
This wheel/tire combo weighs in at 55 lbs.
The tire diameter is .7" taller than stock

2) Junn Lightweight flywheel

3) Japanese Short Gears
Testing was done in 3rd gear for 1st 2 runs
Testing was done in 4th gear on 3rd run

4) K&N stock replacement element

There were a total of 3 NSX's dyno'd that day and we all had a K&N drop-in replacement filter and 3 different types of exhaust systems. I have a Comptech, there was a DC and the other was a Magnaflow. Both other cars just had the 2 mods.

Thanks for your analysis.

 

[1BADNSX]

From an earlier post I tried to explain the affects of rotating mass.
http://www.nsxprime.com/ubb/Forum1/HTML/007313.html


In this post, I also explained why it is impossible for a chassis dyno to accurately measure the difference in performance for changes to flywheels, wheels/tires, or other changes in rotating mass. The dyno will measure a difference, it just isn't the same difference as when the car is actually accelerating on the street. Another item to be careful about is comparing your data to another NSX engine that was measured on a different machine, even though it is the same type machine.

To answer your questions based on calculation:

1) Assuming your wheels/tires weigh 56 lbs more than stock and the weight is distributed mostly at the edge, your wheels/tires cost you anywhere from 1.0 HP to about 4.3 HP. The effect is not constant with speed, nor gearing. The taller tires cost a small amount in additional rotating mass, but otherwise would not affect your horsepower to the road. The taller tire would also change the effective gearing in real life, but it would be a small change like changing R&P.

2) As explained in the earlier post, the effect of the fltwheel can be larger, especially in 1st gear. Roughly the lighter flywheel saves anwhere from 2.5-10 HP in 1st gear, 2.5 HP in 2nd gear, and 1 HP in 3rd gear.

3) Short gears and gear selection make no difference in horsepower to the ground, other than differences in friction. The dyno only measures two RPM's, the engine and drum, and overall gear ratio is only used to convert the drum torque back to crank torque (how it is reported).

4) The K&N filter has no affect. In my back to back tests, the K&N performed 1.0 HP less, but this change is less than the accuracy of the measurement.

Hope any of this helps,
Bob