Is it true that US car manufacturers quote flywheel BHP, and all of the dyno tests on the cars on this site are wheel HP?

So how to compare? I mean - we say Dave's old car/ Mr grumpy's new one is 258.1bhp - what would that be quoted in flywheel bhp?

confused....

Is it true that US car manufacturers quote flywheel BHP, and all of the dyno tests on the cars on this site are wheel HP?

So how to compare? I mean - we say Dave's old car/ Mr grumpy's new one is 258.1bhp - what would that be quoted in flywheel bhp?

confused....

I might be wrong, but when a car is rr'd doesn't it show both flywheel & whp ?

I'm sure I've seen a readout somewhere where both were shown.

You're absolutely right - but whp is used for bragging purposes in the UK.

In the US (and locally here) manufacturer's flywheel hp is what's spoken about - and the fact that the majority of cars here are automatic gearbox, the power loss from the drivetrain is greater than a manual.

Just trying to compare apples to oranges kinda....

btw - how's the aquarium doing?

Bas

btw - how's the aquarium doing?

Bas

Atm, what with me breaking the devils-own thingy by messing with it, and nearly hydraulocking the car, and having done a journey to the tip, and having cardboard boxes as carpets, and having had to empty the wifes car because it is getting traded, and having nowhere to put all of the stuff out of it, because the garage is full of tat ( despite having done a tip run ) the Skip is aptly named.......

ok got some info by googling - flywheel hp is what manufacturers advertise. Wheel bhp is what is recorded by dyno's.

So a manual geared 258bhp one would be advertised by a manufacturer as 258/0.75= 347 HP.

There - you got more hp to talk about

ok got some info by googling - flywheel hp is what manufacturers advertise. Wheel bhp is what is recorded by dyno's.

So a manual geared 258bhp one would be advertised by a manufacturer as 258/0.75= 347 HP.

There - you got more hp to talk about

So, unit per unit, I have as many horsepowers as there are bits of rubbish in my car?

Cool...

ok got some info by googling - flywheel hp is what manufacturers advertise. Wheel bhp is what is recorded by dyno's.

So a manual geared 258bhp one would be advertised by a manufacturer as 258/0.75= 347 HP.

There - you got more hp to talk about

Usually flywheel power is quoted on a rolling road, wheel horse power is calculated by transmission drag on the run down..iirc.

Or it could be the other way around, its too early to remember.

Usually flywheel power is quoted on a rolling road, wheel horse power is calculated by transmission drag on the run down..iirc.

Or it could be the other way around, its too early to remember.

oops.

So I can't brag?

Usually flywheel power is quoted on a rolling road, wheel horse power is calculated by transmission drag on the run down..iirc.

Or it could be the other way around, its too early to remember.

where on the car is the power being measured :P

where on the car is the power being measured :P

I know, I know - those round black things at the front

Wheel hp is first measured at the wheels, this is most accurate. Then a calculation is made to convert it to flywheel power, this is the power we in the uk quote. Probally because its a higher figure. afaik

Odd really considering it's entirely irrelevant what the horsepower at the flywheel is, unless you're powering a belt driven farm implement straight off the flywheel

In the US it is flywheel HP. A common aftermarket upgrade over there has always been a 'crate motor' (a drop in replacement engine) so quoting the flywheel HP makes sense.

Try checking the difference between SAE Gross (flywheel) and DIN Net (flywheel), and make yourself even more confused!