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      08-20-2008, 09:14 PM   #83
Lieutenant Colonel

Drives: Legacy GT - 13.704@99.39
Join Date: Jul 2007
Location: Manheim, PA

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Originally Posted by T Bone View Post
No. By your calculations, what is the impact of weight as speed increases? Drag / Drivetrain losses become a higher percentage of the "resisting" force. Additionally, if weight was the key issue, why is the RS4 quicker to 60 (assuming good traction on the M3)?
Uh, because up until model year 2008 at least, you could wind it up to one rpm short of the limiter and sidestep the clutch? Duh. See below for further commentary.

Originally Posted by T Bone View Post
Modern turbo cars can adjust for ambient conditions much more effectively than N/A cars. Dyno runs can be adjusted or even manipulated as you know. If you know better than BMW / SAE than please share with us.
You're kidding, right? There are probably a couple of dozen strings out there on the net in English (and presumably many more than that in other languages) showing that anybody who straps a 335 to a chassis dyno and gets less than about 275 HP on a stick 335 (and about 265 HP in an automatic) immediately goes running to the dealer, demanding to know what's wrong. The other clue is the trap speed. The cars are going a minimum of 104 mph in the quarter mile, with most seeming to cluster in the 105 - 106 range, at least when density altitudes are at 1000 feet or below. We're talking 330 -340 HP here, assuming 3700 pounds with driver.

Where have you been?

Originally Posted by T Bone View Post
Sure I would expect the XI to be down on from the regular I. But what is not being addressed is the observed performance gaps of the RS4 and other old school Quattro systems.
I'm not opening this up to all Audis built since the stone age, but what part of this (in my last post) didn't you get?

"Look, guy, because of awd and the weight differential, you'd expect the RS4's quarter mile trap speeds to be down by between three and four percent, with the ET disparity closer due to the awd launch capabilities. Near as we can tell from the lists, that's where the cars fall."

Calling it to within about 1% is pretty specific, doncha think?

Originally Posted by T Bone View Post
It is not weight as the significance of the other forces are much higher after say 70 mph.
Other than commenting that weight stays with you from zero to flat out, and aerodynamics loss squares with speed, I have nothing to add on acceleration from, say, 120 to 150 mph. Nothing at all. (It's due to lack of actual knowledge and experience on my part.)

That's not what we're primarily addressing here, though. It's the classic quarter mile, easily addressable through a number of tools and rules of thumb. In that venue, the Audi typically loses to the M3 by just about what you'd expect. Sometimes less, not often more.

Originally Posted by T Bone View Post
Also personally, I remember the A6 4.2 as being slow off the line, a happy 60 - 140 kph type of car and after a few high speed runs, the car was slow.
This helps explain your anti-Audi bias. Mine was a better experience.


Last edited by bruce.augenstein@comcast.; 08-20-2008 at 09:46 PM.