nize

i'd have to calculate for increments, as it will be a curve. thus, solve for 2k-2500, then 2500-3k, then 3k-3500, etc.

hp18racer

Here's one for power as a function of changes in speed...

horsepower = (.00134102209 * ( (weight in pounds* .44704) * ( (V2(mph)*.44704)^2 - (v1(mph)*.44704)^2))) / time

nize

okay, now i just have to convert rpm's to speed. spreadsheet time...

Frank@Work

This might help converting RPM to KMH/MPH:

Excel

toddk911

So with the S2 tranny at 7,100rpm we break 200mph?????

nize

frank, that is awesome. now i just need a column to enter the time between rpm's and can calculate the hp/tq numbers, then use those values to make a graph !

nize

btw frank, where did you get your 951 gear values? the numbers on racerx seems different;
http://members.rennlist.com/951_racerx/gearing.html

1- 3.500
2- 2.059
3- 1.400
4- 1.034
5- 0.829

Bri Bro

I converted the formula to excel with the values in D3=weight, B3=V2, A3=V1 and C3=Time. Took some traqmate data from Mid-Ohio and pluged it in. I was at 40MPH on the start of the back straight and around 136 MPH before braking and that took 20 seconds. I set the weight at 3,000. The HP came out around 300 which is what I would expect, it was a cool day and I was a little over 18# boost on stock turbo. It is interesting to see how much more HP is required to raise the V2 speed by a few MPH.

= (0.00134102209 * ( (D3* 0.44704) * ( (B3*0.44704)^2 - (A3*0.44704)^2))) / C3

Frank@Work

I'm not sure where I got them, but I think there might be a difference between US gearing and the gearing in a Europe.