I wouldI would like to know the general conversion from BHP to WHP on my EVO. I am currently running 347 WHP on a 4 wheel dyno. I am aware of the fact is that Wheels and brake disks are taken into account. I currently have Volk/Ralliart rims can anyone assist me with the calculation like to know general

 

EVO 8
Motec piggy back M400
Os Giken twin plate
Geddy 4 Gauge set boost/oil pres/oil temp/exaust temp
Ralli Art/ Volk Rims balkc with red stripes 18x8.5
Greddy EBC
HKS 272 cams
Greddy evo exaust
GP Down pipe cat delete
ties Yokokama avs 235/40

 

409BHP. Its kind of hard but its been discussed here before, drivetrain power loss. For a Rwd car its about a 15% loss. It is usually more with a AWD car, anywhere from 18% to 20%. I usually use 18% to calculate the loss. 347 x 1.18= 409.46 If you want to get the Whp form Bhp you would divide instead of multiply. 409.46/1.18= 347. The 1.18 represents the 18% loss while adding it. Hope that helps.

 

And what kind of dyno to get your WHP.

 

yeah im curious as well what dyno and if you used c16 or something....i didnt know 347 awhp was something you could achieve on those mods. but im probably wrong

 

It is not a linear loss...Higher horsepower = Higher loss
Yes, the type of dyno you use can confuse the issue as Dynojet #'s are always thought to be inflated, but you are in the UAE so it is doubtfful you are on one of those dynos?
As a rule of thumb with evos/subarus that are under say 500 hp the wheel horse power figure seems to be around 30% less than the power at the flywheel
WrX Kila your 18 % on an AWD car is way too low IMO.....It is normal to see 15-17% loss on a FWD car!
My 2c

 

So what the percentage would be? I always thought it was 18%-20%.

 

For 4wd car is around 25-28%.

 

IMO it's 22-25%

 

That much! I find that a little hard to believe.

 

I even think 25% is a bit low .....

 

I did the the search on the internet for like 5 minutes, I saw 24% that sounds more realistic, Thank you no applause please !!

 

It was probably on a dynojet. Like mine are.

 

I disagree strongly. Drivetrain losses can't be anywhere near 25% across the board. This is self-evident through comparing expected turbo performance with real-world 1/4 ETs.

Higher hp means that the drivetrain is accelerated quicker, so Andrew is correct that higher hp = higher drivetrain loss, simply because it takes more power to accelerate the drivetrain at the faster rate of a higher hp engine. However, higher static drivetrain losses do not automatically equate to higher percentage of engine output.

The load of turning the drivetrain is small in comparison to the load of moving the mass of the vehicle, especially at speed. Therefore, the more power the engine makes, the lower the percentage drivetrain losses comprise of the overall load. Despite the fact that a 600bhp car accelerates the drivetrain at a faster rate than a 300bhp car, the drivetrain loss of a 600bhp car should be significantly less as a percentage of engine output than the drivetrain loss of the same car with 300bhp, simply because pushing the vehicle mass at the rate of a 600bhp car requires much more power than turning the wheels faster in space.

As for the original question, it is impossible to determine "347whp on a 4-wheel dyno" as an expression of bhp, because as mentioned previously, we do not know what brand of dyno. What we do know is that a Dynojet gives the whp reading that is closest to bhp.

 

So Ted are you saying that the percentage is subjective? Or better yet a car that is rated at 469hp ... how much whp that comes out to. What method you are going to use to get the answer.