600 WHP Honda S2000

[jeffw]

Interesting thread here http://www.s2ki.com/forums/index.php?showtopic=519057

600 WHP (700 at the crank ?) from a S2000 engine with a turbo kit on it, with stock internals....that can't be right or can it ? 240BHP standard.

[dummi]

its a racing short block, but 500-600 is feasable on a high reving engine with gt35

[jeffw]

If you read the thread they are getting 600 WHP on the standard high mileage engine...standard compression ratio and everything

[dummi]

yes your right, thats impressive for the standard motor standard compression. don't know about the numbers though, 500whp does not equate to 600bhp for a start, would be good to have it on a set of rollers beside a standard car in the uk if we want to compare it to anything here or even better dyno it from the crank

[jeffw]

So Subaru and Mitsubushi struggle to get much over 400 BHP out of a 2 Lt 4 cylinder engine and a tuner in America can get nigh on 700BHP from a 4 cylinder Hoinda engine....sounds very odd to me.

[Brooner]

That's a lot of horses to the rear wheels

[dummi]

its no where near 700bhp more like 500-600

[GardinerG]

I'm probably going to get flamed for this oversimplification, but I always thought BHP was directly related to RPM. So an engine capable of reving to best part of 10k would be about BHP = 1.9 x Torque in ftlbs.

based on BHP = (2 x Pi x ftlbs x RPS)/550.

So, even at 600BHP torque would only be 315 ftlbs. Still good figures though. Or am I being a N00B?

[dummi]

yes they are related there are differences between whp, hp , bhp though. whp is a calculation from rolling road torque at the wheels. more to the point for numbers would be a crank test for torque, bhp can be calculated with regard to fuel, tq is usually measured but can be calculated from fueling with a known engine efficiency.

still they are good numbers which will be because of the engines extraordinary factory ability to rev 10krpm. the impressive stuff will be more what it can do with whatever power its got

[BRETTCOLLINS]

In japan I think they released A 400bhp turbo version. On a limited run.

[jeffw]

WHP is the measured figure on a rolling road (it's actually torque that is measure but you know what I mean) and is what is used to calculate crank HP. So 600WHP + transmission losses = 690BHP if you assume 15% losses. A 420BHP S4 would make 300ish HP at the wheels.

From Wiki

Effective horsepower / true horsepower / wheel horsepower
Effective horsepower (ehp), True horsepower (thp) or wheel horsepower (whp) is the power converted to useful work. In the case of a road vehicle this is the power actually turned into forward motion as measured on a chassis dynamometer.

"True hp" is generally 10% to 20% less than the engine's "bhp" ratings due to drivetrain losses.

Wheel horsepower (whp) is the more widely used term for effective horsepower.

[S4TAN]

A 420BHP S4 would make 300ish HP at the wheels.

Hmmm ... the last time my car was dyno'd it made 350whp and 495lbf.ft torque .... but was calculated to 415chp (crank HP) ... this equates to a ~15% drivetrain loss.

[jeffw]

Transmission losses are a contentious issue. It is 'normal' to assume 12-17% for front or rear wheel drive vehiicles and 20-25% for AWD. Many rolling roads approximate losses by using run down resistance as a measure of losses.

AMD once gave me a Dyno sheet that had 45% losses.

350HP at the wheels is really good

[BRETTCOLLINS]

I have a print out with 45% losses from AMD. Prob the same one LOL

[dummi]

i still think they need to put base reading before modification. so performance would be more appropriately be a ratio 1:2 where 1 is your oem power on that roller and 2 is the new power

whp is a made up thing from torque measured on the dyno (whp=rpm*tq/5252) that gives it in units, so it all depends on the inertia of the roller and its calibration. its all just numbers without a base reading