Are My Calculations Correct ? Rwkw>rwhp>hp

[robots]

I always assumed that rwkw = rear wheel kw, rwhp = rear wheel hp

kw = flywheel kw, hp = flywheel hp.

Now all the dyno sheets on SAU read in RWKW.

This means rear wheel horse power, right ?

Lets say I got 220rwkw. It means I got 220kw at the rear wheels.

Or 220*1.34=294rwhp and 294*1.1(drive train loss coefficient. 10% is low, but anyway.) = 323hp at the flywheel(crank)

Are my calculations correct ?

Edited November 5, 2008 by robots

[joeyjoejoejuniorshabadoo]

i'd guess at approx 295hp

[The Dan]

I always assumed that rwkw = rear wheel kw, rwhp = rear wheel hp

kw = flywheel kw, hp = flywheel hp.

Now all the dyno sheets on SAU read in RWKW.

This means rear wheel horse power, right ?

Lets say I got 220rwkw. It means I got 220kw at the rear wheels.

Or 220*1.34=294rwhp and 294*1.1(drive train loss coefficient. 10% is low, but anyway.) = 323hp at the flywheel(crank)

Are my calculations correct ?

I'd say it would be closer to 365-370 engine hp

[robots]

One thing I don't understand is than. Lets you got hks2530 turbo. 320hp turbo. And you get 210-220rwkw from it. Which equates to around 340hp. So is there a mistake in the calculations or happy dyno ?

[joeyjoejoejuniorshabadoo]

oops my bad... for some reason i did a straight kw - hp conversion....

yeah i'd imagine 360 odd

[tridentt150v]

Yeah, 15-25% so say 20% average unless your a Holden or a Ford then the factory will make it more like 30-40%.......lol. The 307kw Holdens don't dyno test at 307kw [that figure is a little optimistic].

Depends on your gearbox, diff and/or CV's, wheel bearings, clutch anything that produces friction and heat in the drive train. The more heat the greater the power loss between crank and wheels.

[simpletool]

I use 20% for driveline loss and 0.746 for hp to KW.

So 350hp engine = 280 hp at wheels = 209 kw at wheels.

350hp x 0.8 x 0.746 = 209 rwkw.

In your case that's 220rwkw/0.746 = 295rwhp or 275kw at engine or 369hp at engine. BUT that 20% drivetrain loss becomes less as you get more power with the same driveline. So 369hp might be a tad high. Isn't this a metric society? So you have about 275kw and likely 450Nm of torque maybe a touch more.

[cankas]

Isnt the 20-30% drivetrain loss for a standard car?

206kw flywheel skyline - 25% drivetrain loss = 154.5rwkw which is about right is a drivetrain loss of about 50kw

If the drivetrain doesnt change and all you do is increase engine kw the drivetrain loss figure shouldnt rise very much.

A 300rwkw skyline with an upgraded clutch and flywheel wont change the drivetrain loss much

Therefore 300rwkw + drivetrain loss of 50kw (generous) is only 350 engine kw

If calculate a 300rwkw car at 25% your way off, its a 25kw difference and it grows as the numbers become bigger

[ZENNON]

Now all the dyno sheets on SAU read in RWKW.

This means rear wheel horse power, right ?

[TTT]

I always assumed that rwkw = rear wheel kw, rwhp = rear wheel hp

kw = flywheel kw, hp = flywheel hp.

Now all the dyno sheets on SAU read in RWKW.

This means rear wheel horse power, right ?

edit.. I had more emoticons to make my point but..

THE FOLLOWING ERROR(S) WERE FOUND

You have posted a message with more emoticons that this board allows. Please reduce the number of emoticons you've added to the message

lol... owned by zee germans of old

Edited November 7, 2008 by GTST

[joeyjoejoejuniorshabadoo]

i lol'd

[robots]

U got what I meant, right. Stop pointing out the rear wheel hp thingy. I meant rear wheel kw.

[Bakes]

Whats the conversion for AWKW to engine KW?

ie: 300AWKW = What Kw at the motor?

[PM-R33]

Isn't AWKW in a GTR pretty much the same as RWKW. As under normal driving conditions while accelerating, most of the power goes to the rear wheels anyway? So say if a R32 GTR makes 250kw in AWD it will make like 255kw in RWD? However i suppose with engine power there would be a bit of a difference as you would lose a bit more power through an AWD drivetrain with an extra diff/transfer case etc. compared to RWD.

So therefore it would be a bit more at the engine when comparing a 300RWKW car and a 300AWKW car. I think it will be just stabs in the dark to guess how much extra power those components take away in power loss through heat and noise.

Edited November 7, 2008 by PM-R33

[Bakes]

RWKW and AWKW cant be the same. Flat out on the dyno the front wheels look to be going pretty hard

[W0rp3D]

At the end of the day unless you put it on an engine dyno its only estimated, its what is read at the wheels that counts.

An easier conversion from horse power to kilowatts is that 100hp = 75kw, its not exact i know but its easier to do a quick conversion with those figures.