Rolling road results

[kz]

It calculates the loss from engine to wheels, it's reasonably accurate within 1-3%,

How does it calculate ? It's probably some standard % loss which is complete nonsense. whp is the only number that matters, unless they took engine out, ran it on an engine dyno to get crank number and calculated %loss for that particular car model - which I highly doubt they've done.

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[RoyalGuard]

I've just never heard of a dyno ("rolling road") resulting in estimates and not a real whp number. An estimate is worthless as a tuning tool and to say I have 500bhp doesn't mean jack if I can't get that power to the wheels....

Edit: And how is it a 'problem' when it reports the real values instead of fairy dust estimates?

Is this a common UK thing?

Sorry that didn't read well was writing it whilst on the phone, the problem is not with RWBHP but the estimate power

No it's not a standard loss, chassis dynos are very common over here, it calculated the flywheel BHP and Lbs/ft

If you want I can explain it in great detail later,

 

[WaxDaddy]

I've just never heard of a dyno ("rolling road") resulting in estimates and not a real whp number. An estimate is worthless as a tuning tool and to say I have 500bhp doesn't mean jack if I can't get that power to the wheels....

Edit: And how is it a 'problem' when it reports the real values instead of fairy dust estimates?

Is this a common UK thing?

In the UK most of the time you will see power measured as Brake Horse Power and usually at the flywheel rather than the wheels but most car companies will quote the power in metric horse power (ps).

The dyno measures the power at the wheels using the standard calculation on the torque and rpm. It then measures the drain train losses by measuring the deceleration of the rollers.

After this there is a standard correction algorithm applied designed to factor out environmental factors and make the results reproducible.

The wheel torque + the calculated loss = torque at the flywheel

flywheel torque is then converted into flywheel brake horse power.

None of it is fairy dust or magic, just maths.

 

[stoli]

That's new - never heard of going by bhp on a dyno, only whp. The crazy things you guys do on that side of the pond. .


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[RoyalGuard]

Great explanation! Saved me a lot of time too! :love:

it's also nice to see if you have a dud engine lol,

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