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Bhp @ wheels into BHP @ flywheel

Posted: Wed Feb 14, 2007 8:03 pm
by RSVI
Took mine on the rolling road today just for the sake of checking things over.

BHP at the wheels was 364.

How do you work out the BHP at the flywheel?

Guy had not done an RS6 before and guest it was higher than stock. :D

As far as I'm aware the car's std.


TIA

Posted: Wed Feb 14, 2007 8:10 pm
by ScottyBoy
Do what Subaru drivers do, times it by 5 and divide it by 2.

Posted: Wed Feb 14, 2007 8:54 pm
by RSVI
lol........

http://bbs.scoobynet.com/general-techni ... horsepower


So, do I times 364 by 1.3?

If so that's 490 odd bhp at the flywheel and that's not taking the auto box into consideration. Or because it was in manual does the auto not need converting?

Posted: Wed Feb 14, 2007 9:45 pm
by JonnyX
Take the engine out and put it on an engine dyno. Or just use the ATW figure as it's more important
than the FW figure anyway ;-)

FW figures are just for cock waving....

Posted: Wed Feb 14, 2007 9:52 pm
by RSVI
One reason i wanted to know was to compare to std figures.

Guy doing it seamed to think it was high and someone could have tweaked the ecu.

Posted: Wed Feb 14, 2007 10:06 pm
by GrahamS4
I would have said 100BHP losses wouldn't be unreasonable on that car (although I am sure there must be some RS6 owners that have done the same as you and could confirm) so that would give ~464 - for the sake of 14bhp you can put that down to you having good example or more likely down to some tollerance in the accuracy of the dyno. I believe you have a standard car.

Posted: Thu Feb 15, 2007 12:29 am
by RSVI
std sounds good, that way when i get the extras done it will feel better :D

Any other RS6 owners that have done a RR session? Input would be helpful on this,what did you get at the wheels?

Thanks.

Posted: Thu Feb 15, 2007 10:28 am
by PhilT
Sounds like the Dyno operator needs some training..... Drivetrain loss is measured on the run down, so:

- On the rollers.
- 1st, 2nd, 3rd, 4th from about 1,000 to redline foot to the floor.
- Put the car in neutral and measure the drivetrain loss.

BHP at Flywheel = BHP at Wheels + Drivetrain loss.

Posted: Thu Feb 15, 2007 10:45 am
by GrahamS4
I don't think all dynos work like that Phil. Only an inertia dyno.

Posted: Thu Feb 15, 2007 10:53 am
by bobjebb
All I know about RR from one of the top5 tuners is that the RS6 doesn't get on with them. Results can be woefully innacurate. I think yours is 795bhp... :wink:

Posted: Thu Feb 15, 2007 11:46 am
by viperbl
I had mine done last year at Awesome, who again do it at the wheels.

I managed 376 and another RS4 (chippped my MRC) done 359.

I have stock RS4 turbos, engine, Milltek exhaust/downpipes and hi flow cats. MRC Map.

I think I worked it out at just under 460 bhp at the flywheel...

Results here...
http://www.awesome-gti.co.uk/rollingroad.html

Posted: Thu Feb 15, 2007 12:46 pm
by RSVI
bobjebb wrote: I think yours is 795bhp... :wink:
Thanks Bob, knew i could count on you :D

Don't tell anyone though or they'll all want to know what I've done the the car.

viperbl.
Thanks, i think that information has told me that I'm driving a std car.

Your 376 ATW gave you 460 ATF

So mine i guess is going to be about the same which is what Audi quote.

Or do i need to add more because of the auto box or because it was in the Manual setting this would class as a manual.

Ah well, what ever it is I'm still happy every time i drive her :D

Posted: Thu Feb 15, 2007 12:52 pm
by viperbl
RSVI wrote:viperbl.
Thanks, i think that information has told me that I'm driving a std car.

Your 376 ATW gave you 460 ATF

So mine i guess is going to be about the same which is what Audi quote.
I agree its stock, looks very close to 450 bhp which is correct.

Which is good, room for improvement 8)

Posted: Thu Feb 15, 2007 12:55 pm
by RSVI
viperbl wrote:
Which is good, room for improvement 8)
Elementary dear viper :D

Sounds good to me, plus it's going to be cheaper to go faster ;) if you know what i mean.

Come on Stage one! ! ! ! !