Rolling Road on 24/11/2007

[55JWB]

according to the two plots I received on the day, my B7 numbers are 261.7 bhp at Wheels, 323.2 'estimated' at Crank a 19% difference

I will of course post up the results from my 2nd attempt on the 4th of December...

Jason

[SimonFV8]

according to the two plots I received on the day, my B7 numbers are 261.7 bhp at Wheels, 323.2 'estimated' at Crank a 19% difference

I will of course post up the results from my 2nd attempt on the 4th of December...

Jason

My god surly if you prove that this is correct Audi are going to have to recall all of the B7 RS4's The ramifications of this are massive

[rs-mad]

Guys, i understand your concerns but unless someone/company is willing to remove an engine and place it on an engine dyno your "estimated" crank HP/KW figures will never stand up.

Much easier to go to a local drag strip and use the MPH to determine your HP.

[ChrisRS4]

I just dropped my S3 off at Star Performance for some work and had a chat with Jim about rolling roads and the RS4. He says that its not done in sport mode you'll only see about 330bhp, and in sport mode most seem to make about 390bhp. Hadn't seen any make the magic 400.

[MarkB]

He says that its not done in sport mode you'll only see about 330bhp.

Have you missed an 'if' out?

He says that if its not done in sport mode you'll only see about 330bhp

[GrahamS4]

If 16.5% is the calculated drivetrain/transmission loss for a B7 RS4 does anyone know the accepted loss figure for a B5 S4/RS4? Just interested to know (and I'm sure a few B7 owners would have owned a B5 previously)

e.g. At the recent RR day I got 314 measured@wheels, 406 calculated@crank - which equates to around 22.6% loss. Is the higher transmission loss for the B5 due to old-technology or just old/worn parts? (7 yr old car)

While the research Simple1 has quoted seems good - ie test the engine out the car then dyno the car a\nd compare- the figures at the wheels sound to me far too high, making the difference too low and the tranmission loss % too low. Much lower than I have ever heard quoted in general. At the time this was discussed and I think the general opinion.

[simple1]

This particular rolling road seems quite accurate, they ditch the tyre rollers and bolt the dyno heads direct to the hubs getting rid of any tyre slip etc. Think my car showed just about 350 at the wheels on standard dyno.
To answer S4tan's question, I think the drive train loss in the B5 was about the same, my car tested standard, showed 347 bhp, when corrected 402 I believe I was told. The only mod at the time was a miltek exhaust. Was carried out by AMD as I had complained about a lack of power, turned out to be DV fault and once these were replaced, increased reading by about 38 bhp to those quoted.

[mrdeli]

Well what a great morning - Demon Dyno in Ness, Wirral - Highly recommended + with the very latest Dyno kit - I am confident the results are very accurate. (As a bonus the guys running it are super nice). Anyway.....

Graphs below show results for the Daytona coloured car first, then the Avus car - (both cars are 2007 with 3000 miles - no mods).

First plot shows at wheels power, then at crank

[mrdeli]

Avus....

[mrdeli]

On the road...

[mrdeli]

Video of the test...

http://www.youtube.com/watch?v=_7mmMJcRDG4

[hogster]

Im just happy that im driving the most powerful colour

[ChrisRS4]

He says that its not done in sport mode you'll only see about 330bhp.

Have you missed an 'if' out?

He says that if its not done in sport mode you'll only see about 330bhp

Oops, yes. At least you understood what I was trying to say. Thanks

I just had mine on the rollers this morning. It still didn't make the Audi claims, but I was reasonably happy with 320whp and 395bhp at the flywheel.

[simoncotton]

I'm hoping to get my MTM B5 up to Dyno Demon. I know the owners
pretty well and there top guys, excellent set up, all brand new. Had one of my other cars on the dyno on 2 occasions and they print out almost the same, very accurate.

check out the RS6 that was a dyno demon recently..

http://www.flickr.com/photos/15173730@N02/1597430586/

Anyone fancy an RS Dyno Day?

[GrahamS4]

Interesting. Thanks for sharing. The same shootout mode as the B5's were run in at Thorney last week although we ran in 4th gear not 3rd. Unless that 60/40 is playing tricks with teh dyno (I personally think not) it's a good comparison.