Wheel to Eng KW.

[mikek73xu1]

What is the consensus with 300 rwkw to engine kw with an M6?
I know people have all different ideas on this - i reckon 350.
Hopefully someone on here has done a comparison with an engine on a dyno then installed and put on a chassis dyno.
Cheers
Mike

[VZSSTT]

could be wrong but i thought fwkw roughly equalled rwhp? hence 300rwkw = 402.3070HP Which is approx 400KW at the engine?

[BlackCalaisVVE]

You cant really do a real comparison on this, but for a manual you lose between 18-25% through the flywheel. So anywhere between 354-375 FWKW
Auto will lose more up to 30%. But remember each dyno is different as well.

[Vulture]

You cant really do a real comparison on this, but for a manual you lose between 18-25% through the flywheel. So anywhere between 354-375 FWKW
Auto will lose more up to 30%. But remember each dyno is different as well.

A set percentage or a set HP? I think you'll find losing 30% of 1000hp, for example, is a pretty big (and also incorrect) number!

[mikek73xu1]

What i do know is before modifying it was 257rwkw so on a GTS300 this is just over 14% loss so by that calculation i've arrived at 350. [350 - 14.3%=300]

[BlackCalaisVVE]

A set percentage or a set HP? I think you'll find losing 30% of 1000hp, for example, is a pretty big (and also incorrect) number!

I was talking about KW not HP. So how would you define a correct number i believe this not possible unless you stick the engine on an egine dyno.

[VTR8Clubby]

What i do know is before modifying it was 257rwkw so on a GTS300 this is just over 14% loss so by that calculation i've arrived at 350. [350 - 14.3%=300]

I think you would find most dynos would have read around 220 to 230kw mark for the 300kw engine.

[mikek73xu1]

I think you would find most dynos would have read around 220 to 230kw mark for the 300kw engine.

I should clarify a bit more - apologies.
This car had been on 2 different dynos within about 6 months.
Ist time it went on and had an EFI Live tune done but otherwise std and did 245rwkw.
I then bought the car and put a pod filter on it then went to another guy who ran it up before we did the cam etc and he got 257rwkw - he has done a sh*tload of LS1"s and said it was the strongest GTs300 he had seen.
Now i know you dont get 12kw from a pod filter but what it does back up is that it was up there in the 245 - 250 region.

[Vulture]

I was talking about KW not HP. So how would you define a correct number i believe this not possible unless you stick the engine on an egine dyno.

Kw or HP, doesn't matter. No such thing as a set percentage of power loss. I was trying to explain that using the example of a 1000hp car. Imagine if it lost 30% of 1000hp (or Kw if you prefer) through the drivetrain.

[VZMY06SS]

Can't compare a GTS 300's rwkw's to it's engine figure, as from what I've read the engine figures were taken without all accessories attached. There are also heaps of variables on a dyno, as well as in your car...

[lowhsv]

my car auto 5.7 untuned made 196rwkw then he done a engine kw it made 247.5fwkw. something to go off.

[MJR-57T]

could be wrong but i thought fwkw roughly equalled rwhp? hence 300rwkw = 402.3070HP Which is approx 400KW at the engine?
Thats what ive always known as a rough guide.

Work out the FWKW into RWHP then convert the RWHP back into RWKW
It's not textbook acurate but gets you into the pub talk ball park

[White Rider]

A set percentage or a set HP? I think you'll find losing 30% of 1000hp, for example, is a pretty big (and also incorrect) number!

I like your way of thinking, losing 300hp is pretty wrong

[duz12s]

to confusing for me,the strip tells me what hp/kw's you got

[GTS_365]

The difference the car has from factory, is the same difference it will always have. For example a GTS with 300kw on the motor is approx 225 kw at the wheels (according to GTS owners I know). Now that's a 75kw difference between rwkw and fwkw. If that same GTS now has 320rwkw, due to heads/cam or supercharger it will still lose 75kw, therefore power at the motor will be 395kw. Or if it has twin turbos and now has 380rwkw, the engine power will be 455kw.

[seedyrom]

http://www.ls1.com.au/forum/showthread.php?t=69960&page=3

Read Justice R8's post (#32) and subsequent posts by NickS.

Very interesting

[Delft Maloo]

Kw to hp conversion is about x 1.34% and the other way round if going from hp to kw, this formula does work fairly often for converting engine-wheels.
A fair portion of cars will dyno out a figure in rwhp that is pretty close to the the engine's fwkw rating.


As for the argument about 1000hp cars losing 300hp at the wheels why not? if a car has a drivetrain loss of 30% or even 50% at a said power how would this percentage change based on the engines power? it wont.. If you car has 30% drivetrain loss with 300kw it will still have 30% loss with 1000kw, it is the loss after the motor so the engines power has no affect on it.

[vz6.0]

how does one dissipate 300hp worth of friction without towing a trailer load of oil coolers?

Fair dinkum, for such a "smart" forum, geez i read some crap sometimes.

hp at wheels equals kw at flywheel?

Bollocks

My t400, 3.5" tailshaft, and spooled 9" on slicks wont lose that much.

man, i hate dyno threads..

Get 3 opinions from real experts, and make it a sticky, so all of OUR bullshit "rules of thumb" dont get trotted out every couple of weeks.

[Delft Maloo]

how does one dissipate 300hp worth of friction without towing a trailer load of oil coolers?

Fair dinkum, for such a "smart" forum, geez i read some crap sometimes.

hp at wheels equals kw at flywheel?

Bollocks

My t400, 3.5" tailshaft, and spooled 9" on slicks wont lose that much.

And ive proved it.

I and no one else stated that there are exact figures for everything so get off your high horse.
You hate dyno threads? dont post in one then............
The loss % between B-C wont change no matter what figure A is.

[vz6.0]

The loss % between B-C wont change no matter what figure A is.


Prove it.....But then again, i dont need you to, because youre wrong, but i guess the supposed flywheel figures of a lot of cars arent as pretty if we let a little thing like the truth get in the way.

Answer me this:

Where did the lost horsepower go? It sure as shit didnt get "used" by the transmission, because you cant destroy energy only change its form.

So all those ponies are in there somewhere, what happened to them?

300 from 1000 is a lot to up and disappear, but im sure youll tell me how lol.

[MARS]

Energy lossed in heat generated due to friction.

[VZ_V8]

I don't know how people think that using a % value is at all a viable option.

Say I take 20% as some of you are mentioning, if I have a car with 200rwkw your saying that I have 200*1.20 = 240fwkw, fair enough...

Now if I take that exact same car with a new engine that makes 2000rwkw im now making 2000*1.20 = 2400fwkw

So your saying that the exact same driveline is now magically converting 360kw of power into another energy form which results in loss of power, I think not....

[BlackCalaisVVE]

Kw or HP, doesn't matter. No such thing as a set percentage of power loss. I was trying to explain that using the example of a 1000hp car. Imagine if it lost 30% of 1000hp (or Kw if you prefer) through the drivetrain.

But the question wasnt about a 1000hp car. I said there was no accurate way to measure this without using an engine dyno. What i also said was a good way to look at it was percentage in his case as with most of the commodores dynoed stock they seem to be losing about this percentage through the drive train.
Also keeping in mind No engine is the same and im sure if you put half a dozen l98 or Ls1 engines on an engine dyno(stock engines) they would all come out with different figures.

[vz6.0]

... I said there was no accurate way to measure this without using an engine dyno. What i also said was a good way to look at it was percentage in his case as with most of the commodores dynoed stock they seem to be losing about this percentage through the drive train...

this is actually a pretty accurate statement, and it will be thereabouts if you dyno 50 stock commo's from fly to wheels you can indeed see a pattern which i suppose correlates to a percentage loss, no issue there!

The pattern may even correlate to most common builds up to a certain hp level.
--------------------------------------------------
However, "we" simply CANNOT extrapolate this percentage as an arbitrary figure for all rear wheel figures, for all combinations, just because the driveline remains the same for that vehicle.

Its simple physics, not some unvalidated forumites dig at others, I suppose I could just ignore it and not post, but people read this crap and run with it, because its on the forums, it must be the truth.

I look forward to a real expert entering this discussion, then perhaps it may not become the shitfight it always ends up, when someone disagrees with the ill concieved "rules of thumb" for every bloody thing.

so wheres the 300hp end up on a 1000hp donk if 30% ish is the "magic number"

If im wrong Delft Calais, ill happily apologise to ya, and stay out of the dyno threads...

[myss427]

Was speaking to the guy's from Mansweato at Summernats about this same topic, my 427 engine dynoed at 687 horses but in the car only went 420 at the tyres, I was wondering why the big loss they said large slipery converter and auto was probably the main reason. they changed their auto out of the capri to manual and picked up 300 horses. They told me with there capri, back to back dyno tests showed a 31% loss with the auto.

[White Rider]

I'm willing to bet its somewhere in between, as wrong as losing 300hp on a 1000hp engine is using a set %, it cant be a exact set loss of HP either coz a 20HP engine will surely turn the rear wheels of these cars (somone suggested a flat 75kw loss meaning ud need more than that to even get the car moving).

So while I dont know what it is, it may be some variable loss and its probably more to do with engine torque than power.

[vz6.0]

i never suggested it was a fixed number either, before i get blamed for saying that lol.