Power measurement
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Joined: Mar 2002
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From: Netherlands
C270CDI Avantgarde 2001 Sedan AMG rims and skirts
Power measurement
I've been playing with the AP-22 I recently bought from Race Technology. It turns out to be a really cool box. It can do G-force measurements for breaking and accelerating and for corners. Just like other boxes it can do a measurement of the HP at the wheels, and if you feed it the right data, it does it pretty good.
After the first runs I thought about the possibility of making HP graphs over a range of revs in stead of only 1 measurement. As the data the box logs can be downloaded to a PC you can modify the data. Problem is, it can't measure the rev's of the enige. It does however very accuratly measure the speed of the car. So by doing some math (wheel radius, gear ratio, final drive) I was able to get the rev's of the engine. As an added bonus I could also calculate the torque at the wheels.
Attached is the graph I got for my car (in third gear).
I tested it on a few other cars (and even a motorcyle
. It seems to be reasonalbly accurate, if you take the factory horsepower and take the transmission loss into account.
Spec for my car is 170HP. I guess it does around 15% transmission loss, so you should get about 145HP at the wheels...
Mark
After the first runs I thought about the possibility of making HP graphs over a range of revs in stead of only 1 measurement. As the data the box logs can be downloaded to a PC you can modify the data. Problem is, it can't measure the rev's of the enige. It does however very accuratly measure the speed of the car. So by doing some math (wheel radius, gear ratio, final drive) I was able to get the rev's of the engine. As an added bonus I could also calculate the torque at the wheels.
Attached is the graph I got for my car (in third gear).
I tested it on a few other cars (and even a motorcyle
. It seems to be reasonalbly accurate, if you take the factory horsepower and take the transmission loss into account.Spec for my car is 170HP. I guess it does around 15% transmission loss, so you should get about 145HP at the wheels...
Mark
Last edited by mverboom; Nov 3, 2002 at 01:33 PM.
