WHP vs HP

[n0va91TSI]

I just read somewhere that a WRX STi has 220whp and 300hp at the flywheel.

I have a Talon TSi with 190hp...

Is that rated at the wheel or flywheel?

 

[2gGSX]

flywheel

 

[n0va91TSI]

whats it rated for at the wheels?

 

[DSMeclipse4G63]

youd have to dyno it...but something like 145whp for awd and 175 or so for fwd. Thats because of the awd drivline loss...2g awd dynos usually 155 or so stock.
Andrew

 

[midnght]

The 1g was underated from the factory. You are probly that at the wheels.

 

[n0va91TSI]

ok now im confused

getting conflicting answers

anyone else wanna back up one of these replys

 

[Defiant]

You really need to dyno a specific car, and several of the same model to determine hp. Oddly, manufacturers are as keen on lying about power output as teenagers are.

Oh, and that 30hp loss for AWD is probably off by a factor of slightly over two.

 

[n0va91TSI]

Well i just wanna know the stock AWD WHP. Or at least a rough idea. plus or minus 10 hp.

Surely someone must have put thier stock car on a dyno as a baseline before hooking it up.

 

[dsmturboawd]

Originally posted by midnght
The 1g was underated from the factory. You are probly that at the wheels.

if youre saying he has 190 at the wheels, please pass whatever it is youre smoking.

from the dyno sheets ive seen, its usually about a 60hp loss for awd. that # gets slightly smaller as you start making huge amounts of power.

 

[Violater101]

Yeah, they don't make 190 at the wheels stock. Perhaps only if you do the free mods and turn up the boost. Usually AWD's lose around 20% so 190*.8=152 roughly. Like they said though, each car is different.

 

[midnght]

Originally posted by dsmturboawd
if youre saying he has 190 at the wheels, please pass whatever it is youre smoking.

I just didn't quote the post above the one I posted is all. I don't think he has the same hp at the wheels as he does at the crank.

 

[ckozlgod]

220whp for an sti? I dont think so....

 

[clownface]

Originally posted by ckozlgod
220whp for an sti? I dont think so....

no no, thats about right, it might be a tad more though. they make like 300 or somewhere in that area at the flywheel.

 

[ckozlgod]

Shouldn't it be a 15% loss from the flywheel?

Should be around 245...

 

[herostar]

Originally posted by ckozlgod
Shouldn't it be a 15% loss from the flywheel?

Should be around 245...

that sounds more correct

 

[clownface]

Originally posted by ckozlgod
Shouldn't it be a 15% loss from the flywheel?

Should be around 245...

well, i think ill say most AWD cars have about a 20% Driveline loss if its a manual(i think), im not 100% sure what a STI has at the wheel but if it had 300hp then it would have about 240whp, something like that i guess.

 

[ITSME4G63]

Originally posted by ckozlgod
Shouldn't it be a 15% loss from the flywheel?

Should be around 245...

Actually 17%

 

[KeltonDSMer]

Yeah, I think 1Gs are underrated from the factory because a HP competition at RMDSM showed AWD stockers making anywhere from 145-175 WHP and this is at 6000ft...

I think the drivetrain loss for AWD is even more than that too; like 20-23%. This would mean flywheel numbers are even higher than that.

 

[midnght]

The dyno results for a Stock STi is:

Displacement: 2457cc
Bore & Stroke: 99.5mm x 79.0mm
Compression Ratio: 8.2:1

Flywheel:
300 hp @ 6000rpm
300 lbtq @ 600rpm

Wheels:
257 whp @ 5400rpm
266 lbtq @ 4000rpm

With a Redline at 7000 rpm

 

[NewB2dsm]

ok rwd cars are around 17% fwd is abotu the same and our awd cars sit around 20-22% loss

I made 290awhp so thats around 350hp at the flywheel

Also as you make more power you loose more to the wheels b/c 20% of 1000 is going to be more than 20% from 500.

so awd car lets say 21% loss

300awhp = 363hp crank hp. loss off 63 hp

400awhp = 484crank hp. Loss of 84hp

so therefor as you make more hp you loose more power.

 

[SpeedFreak03]

Yea thats how percentages work...like you spend (or make) more money you get charged more tax

 

[Groomz]

Driveline loss varies from vehicle to vehicle, even on rwd or fwd or awd vehicles. There is no specific percent for a type of driveline. Once you start modding your car, do not care about the flywheel horsepower or torque. Go with the dyno wheel numbers. What power makes it to the ground is what matters, not what is made at the crank. You could have 1000 crank horsepower but be putting down only 50whp and not be going anywhere ( just an example ). What makes it to the wheels is what moves the car.

Back in 1999 when Ford went IRS on the Mustangs, they were rating the motor as 320 crank horsepower. Lots of customers were dynoing around 250whp and wondered where the power was going. Apparently the Big Oval overestimated the power output just a pinch and had to recall them to fix it. Hence now they underrate the new blown Cobra's to make up for it ( just what I think, most blown Cobra's put down 370whp stock ). Just goes to show its whats at the wheels that counts.

Happy Dynoing

 

[clownface]

oo,okay i understand better now

 

[SoSprayMe]

Originally posted by Groomz
Also driveline loss is a little misleading. A 210hp DSM should put down around 160-170whp. This calculates to around 19% loss through the drivetrain. A 500whp DSM is not losing 100 horsepower through the driveline. It is still staying around 40hp. It takes a certain horsepower and torque value to turn the gears in the transmission, not a static percentage. And this is why wheel dyno's are even more important.

Happy Dynoing

Eh, it actually is a static percentage. I know for a fact that with the RWD Mk4 Supras the power loss from the Flywheel to the RWs is 15%(14.#%). With most 2WDs though its around 16-18%. Subaru's are pretty constant by losing around 25%. And with our cars we can lose as little as 20% or as much as 35%. Given the car's condition and modifications.

WRX's rated at 227 dyno'd in at 168whp. That's 26%
3000GT VR4 put down 244whp but 320hp rated at the flywheel. Thats 23.75%.
Marcus Frost's SP73 Single Turbo dyno'd 833rwhp and 980hp at the flywheel. A healthy 15%

Respects,

 

[Groomz]

Originally posted by SoSprayMe
Eh, it actually is a static percentage. I know for a fact that with the RWD Mk4 Supras the power loss from the Flywheel to the RWs is 15%(14.#%). With most 2WDs though its around 16-18%. Subaru's are pretty constant by losing around 25%. And with our cars we can lose as little as 20% or as much as 35%. Given the car's condition and modifications.

WRX's rated at 227 dyno'd in at 168whp. That's 26%
3000GT VR4 put down 244whp but 320hp rated at the flywheel. Thats 23.75%.
Marcus Frost's SP73 Single Turbo dyno'd 833rwhp and 980hp at the flywheel. A healthy 15%

Respects,

So I was wrong on a few parts. My question is why? Can someone explain why it is a percentage loss versus a specific amount to turn the transmission? It doesn't make sense to me that a transmission could take more power away as the power level increases, as a percentage loss would do. Someone correct me. Being wrong sucks.