Does anyone know how a HC calculates its speed?

[DGatzby]

No tune other than DC Stage 2.

Based on the car's sensors, the computer in the car tries to limit the car's speed to somewhere around 203, my speedo showed 202. This is the speed the car "thinks" it's going. The actual speed is measured by breaking a pair of beams set up on the runway.

Oh. That is what I though after I posted.

Then. Use larger diameter tires. Actual speed will be more than system feedback.

 

[2ndAmend]

Oh. That is what I though after I posted.

Then. Use larger diameter tires. Actual speed will be more than system feedback.

Yeah, I figured we had some crossed wires, we usually understand each other well!

 

[2ndAmend]

The better tires were on the front last time. I didn't think of it before the conditions changed that I should swap f-b, missed a perfect opportunity.

I'm going back Sept 7-9. I checked, the better pair have .030" more tread than the other. I will swap them and hope for another tailwind.

The .030" calculates to about 0.4mph. With a lot of luck, if I have a good tailwind, and if the PCM looks only at the rears for speed, I should see 205. Lot of "if's" but I guess that's racing.