2005 A4 stock baseline dyno

jbp · 11-11-2006, 06:10 PM

Two friends and I went to the dyno on Friday. I've got movies of the power pulls and 1/4 mile runs on my webpage http://www.jbperkins.com/dyno_11_10_2006/index.html
The other two cars were a 1996 Trans Am 383 and a 1971 Buick Skylark 455. I've got the peak numbers listed on the webpage and I'll put up the dyno charts when I get them scanned or get the data and plot it. This was a Mustang dyno so the numbers are a bit lower than you'll see on a DynoJet. Even assuming the most conservative drivetrain loss factor (18%) the motor is making the advertised power. The guys at the dyno seemed to think the LS2 was under-rated by GM to keep previous year Z06 owners happy. Sounds reasonable to me. I used to do tuning at a shop that had a DynoJet. They used 18% as the correction factor for an A4. That number was accepted by the F-body community back when I was into those cars. The Mustang dyno guys said to use 25% to estimate crank HP on a A4. So for 18% I would have 400 crank HP and 25% comes out to 437. 437 sounds high for a box stock motor. Anyway, it's a baseline. The AFR was 11.8 around 3500 RPM and 11.2 at 6000 RPM. There is some power to by had by leaning it out a bit.

EEZ GOAT · 11-11-2006, 10:29 PM

what gear did you have it in on your run? and to what MPH

jbp · 11-11-2006, 11:34 PM

Third. The HP peaked at 127 MPH. We started taking data at 79 MPH to miss the 2-3 shift ran it up to 130 MPH. Automatics are tricky on the dyno.

jbp · 11-11-2006, 11:53 PM

Think about this. The LS2 is rated 400HP at 5200 RPM. They don't really say what the HP is at any other RPMs. So if if take my dyno chart and pull off the number at 5200 RPM it is 304 HP. The drive trains loss factor to get from 304 to 400 is 24%. Apply that 24% to the peak HP of 328@5960 and you get 432 HP at the crank.

EEZ GOAT · 11-12-2006, 12:38 AM

Quote:

Originally Posted by jbp

Think about this. The LS2 is rated 400HP at 5200 RPM. They don't really say what the HP is at any other RPMs. So if if take my dyno chart and pull off the number at 5200 RPM it is 304 HP. The drive trains loss factor to get from 304 to 400 is 24%. Apply that 24% to the peak HP of 328@5960 and you get 432 HP at the crank.

holly enstein batman.

j/k

jbp · 11-12-2006, 08:20 AM

Just trying to make sense of the data. It's more of the question is it believable. 431 HP from a stock motor sounds like a bit much. But on the other hand when the LS1 came out in the f-bodies it was under-rated by 50 HP.