rolling road!!

[Big Iain]

Who has had there car rolling roaded?

what do the figures all mean??

in order on the graph I have:

Norm power P-norm to DIN 70020
Engine output P-eng
Wheel output P-wheel
Drag output P-drag

I know what the wheel output is and obviously the dr but what is the actual power of the engine?

 

[edde]

WHeel output is the only import one the rest are often guessed values.

Some places say engine power losses are 130% of the wheel value the best way though IMO is to say add 10hp to the at the wheel and then times by 1.1.

However if you get a car with aircon conpressor PAS etc and compair it to another without the car without PAS etc will be more powerful even if its an idential engine as the power the PAS saps isn't taken account for in the calculation.

IMO it doesn't matter what you have engine wise its the wheel Hp which is the key.

 

[Big Iain]

ok so is 133 @ the wheels ok for a 172?

 

[edde]

ok so is 133 @ the wheels ok for a 172?

Bit low sounds like somthing might be wrong or its a slow one.
140~4 is about adverage ATW.

Yozzasport to give you an idea tuned a car which had 127ATW they found it was so low since it had a broken cam follow ie it was a 15valve not 16 engine.