What is the difference HP measured on tyres and engine ?

[ilker]

I put my car on a dynamometer and we measured its power as 85 hp. But its shown on the technical data sheet given by factory its shown as 90 hp. The mechanic says that it is a normal condition because the power on tyres and on the engine are different. Actually my car is modified a little bit. Performance air filter, V electrode platinium spark plugs, exhaust system etc. I was expecting more power indeed. I wonder how much HP shown less on dynamometer for a standart car as 90 hp ? I mean is it normal to read 80 hp on dynamometer for a 90 hp car ?

[4doorGL]

90hp is what your car makes at the crank.

The dyno is measuring the power your car makes through the tranny and to the wheels. The transmission is where the loss of power comes from.

[somefreak]

technically you have made more power, in those figures your showing a drivetrain loss (it creates friction afterall, you dont get something for nothing) less than 5% loss is impossable in an accent. Thats why i think you have increased in power, i would have assumed a ~20% loss for a standard car, so 72hp at the wheels. You have a good 8hp at the wheels increase, which would probably translate to having over 100hp at the engine now. (rough figures only)