Hp Question

[seanisonfire]

my dyno readout sats 240hp

now is that rwhp??

i just wanna know if there are different readouts on different dynos?? like do some do rwhp and some do just hp? whats the diff

[PM-R33]

Yep HP@wheels. (RWHP)

Only way you can get engine horsepower on a dyno sheet is if the engine has been out of the car and put on a engine dyno (highly unlikely).

[dnbosiris]

I think you can estimate engine HP from rwhp fairly easily

If a stock r33 has 187kw @ the engine and roughly 140rwkw

then that's a 25% drivetrain loss (25% of 187kw is 47kw)

assuming the same drivetrain loss, if you have 240rwhp then you would have approx 320hp at the engine.

[scathing]

Only way you can get engine horsepower on a dyno sheet is if the engine has been out of the car and put on a engine dyno (highly unlikely).

Not necessarily. Some dynos let you calculate flywheel power, which is about as accurate as the rear wheel power.

The dynos will continue to measure after the driver lifts off (I'd assume they have to put the car in neutral). The speed at which the rear wheels spin down gives the dyno an idea of the drivetrain loss, which it can then use to calculate the flywheel power.

It's not a common practice in Australia, but I know quite a few UK dyno operators will do this.

[Newy]

not trying to get into a debate, but i highly doubt standard r33s are still making 140rw kw being 15 years old or so! i threw mine on the dyno to see... it made 160hp@wheels and developed anout 6 1/2 psi... completely standard motor/exhaust/clutch. but thats off topic lol

[madbung]

I highly doubt there's a nation wide conspiracy between skyline owners and dyno operators.

Seems you're the odd man out..

[PM-R33]

Not necessarily. Some dynos let you calculate flywheel power, which is about as accurate as the rear wheel power.

The dynos will continue to measure after the driver lifts off (I'd assume they have to put the car in neutral). The speed at which the rear wheels spin down gives the dyno an idea of the drivetrain loss, which it can then use to calculate the flywheel power.

It's not a common practice in Australia, but I know quite a few UK dyno operators will do this.

Hmm very interesting, never heard of that before. I'm going to do some reading on that, cheers man.

[Newy]

If you are refering to my above comment, all i was saying was that these cars are gettign old and in stock form i highly doubt they would still make the same power they were claimed to have from the factory new. Back on topic, the 240hp would be At the wheels, yes!

[blind_elk]

I think you can estimate engine HP from rwhp fairly easily

If a stock r33 has 187kw @ the engine and roughly 140rwkw

then that's a 25% drivetrain loss (25% of 187kw is 47kw)

assuming the same drivetrain loss, if you have 240rwhp then you would have approx 320hp at the engine.

Try 180hp @ flywheel (unless, of course, you actually make hp through the drivetrain)

[PM-R33]

Huh? Where does he say it's making power?

[jase-r34]

Try 180hp @ flywheel (unless, of course, you actually make hp through the drivetrain)

Lol if a 240rwhp car is only making 180hp at the fly, Then it IS gaining power through the drivetrain...

[seanisonfire]

thanks for the info guys!!

[scathing]

Hmm very interesting, never heard of that before. I'm going to do some reading on that, cheers man.

I just did some more Googling on dyno "coast down" techniques. A lot of places rubbish it as inaccurate (here and here).

[dnbosiris]

Try 180hp @ flywheel (unless, of course, you actually make hp through the drivetrain)

what on earth are you on about?

240 rwhp = approx 320 hp @ flywheel.

[FloydWestwood]

loving so much bold text in this thread.