soo i was in barnes and noble yesterday reading a car magazine.. dont remember which magazine it was but it had an 04 s2k which lost over 50 hp!!! it was one of those articles that showed how much gained from each mods such as headers, exhaust, etc.... but iwas jus wondering how did an s2k go less than 200 hp??? any explainations

 

Honda measures the amount of horsepower that an ENGINE produces. Thus the horsepower is measured at the crank. 240 crank horsepower.

For tuner magazines, they can't readily yank the engine out of the car and measure so they measure it using a dynamometer that measures horespower at the wheels. This is where they have the car on rollers to see how much power the car actually puts to the ground. This accounts for the power loss at the drivetrain (i.e transmission, axles, driveshaft, differential, etc). Usually its about a 15% loss or so. If the magazine states 200 whp, thats 200 wheel horsepower.

Most stock S2000s dyno between 190-210 wheel horsepower. This is dependent on the type of dyno they use.

 

Yeah, as does every other car manufactor. They all use crank HP instead of whp. I personally think its a marketing scheme more so then anything else.

 

If it was the May issue of Import Tuner, then that was my car. It was on a superflow dyno which like stated in the magazine article is stingy with numbers. But like the others said, it is whp not crank horse power. Also the car is a 03.

 

Like everyone said, the magazines use numbers produced by something called a dyno machine.

Car manufacturers generally use bhp (brake horsepower?), which is also known as horsepower at the crank or flywheel.

Mag/wheel h numbers take into account frictions and inefficiencies of the drivetrain.

Not sure about this, but generally, you could expect somewhere arund 15 to 18% for more FR manual transmission cars. Auto trannies could lose a little more ... someone please correct me if I'm really off

 

Sounds about right to me. Let me just add that all AWD cars lose even more HP to the wheels, for obvious reasons. This is why cars like front drive or rear engine rear drive cars like a porche run faster acceleration times with what seems like less Hp. They lose less in the shorter drive train.

 

Makes the car sound like it has more power.

 

It's not a marketing scheme. It's the way car manufacturers have been measuring power for decades, long before there was a chassis dyno on every wannabe tuner shop.

 

Wheel dynos are relatively new. OEMs have been using brake dynamometers since the beginning.