aessis

Can anyone provide me with the mechanical engine and drivetrain differences between a 2006 A6 4.2 and an RS4 same year? The motor is the same size but produces nearly 100hp more. I would love to know if an RS4 intake would fit on A6 motor. The more details the better. Thanks!

ELEVENS

Not sure about that but here's a good foundation for learning about the 4.2L motor in the RS4 and the detuned version in the Q7:

http://www.s4-mtm.com/images/RS4V8-StudyGuide.pdf

DrCondor

This is from memory:
Audi claimed that they did 3 years of R&D for the RS4 motor. The 4.2 configuration in the B6S4 (343 hp/317 foot pounds/~7,000 rpm) was treated to very much lightened internals, and, I believe, improved breathing, plus direct injection. The result was 420hp/about the same footie poundage/8,250 rpm). I do not know the specifics of the A6 4.2, but as you should know, the venerable 4.2 'platform' has been around for a long time and numerous outputs.

I would proceed cautiously...always easy to get a bit more from exhaust and intake treatments, but much easier to spend a lot of bucks second guessing Audi engineers without much in the way of results.

When they launched the RS4, and Audi engineer was quoted (smiling at the time) as saying 'the tuners won't get much more out of this engine'. While there have been modest gains reported through exhaust treatments, and at least one forced induction treatment, I note that the RS5 is a modest 30 hp stronger (sounds fantastic tho, and all four tires can smoke in launch control).

...and big thanks to ELEVENS for the Study Guide. Wherever I go with the S6, my RS4 and its brilliant engine will always have a special place in my driving history.