pedro2m

So I don't know that much about cars, which is why I am on this site - to get some knowledge. I note the post that says it's a waste of money to get the APR chip upgrade for a normally aspirated engine - can someone explain to me why this is the case? Is it because the hp/torque gains are not that significant? I note that the APR chip for my car would increase hp from 435 to 453 and torque from 398 to the mid 400s. Those gains sound ok to me, although chipping some turbos appears to provide much larger gains. Any other issues or concerns? I am considering the APR Stage 1 chip upgrade for my '07 S6 (5.2L V10) and want to make an educated decision here - thanks for any info you all can provide.

MP4.2+6.0

Wrong board. Try C6 A6/S6 board in general. Still, a few pointers from the D3 (S8) side:

Obviously there is a difference from stock S6 to stock S8 tune of 15HP, you can look into where that is. Typically not well documented. Sometimes it is just on paper though to keep higher end model a little distinguished. If real, could be in how far they let throttle plate(s) open at max electronically, or could be different throttle bodies. A few mm smaller on S6 perhaps--call it an Autobahn restrictor plate of sorts. Can look at part #'s for those; I had a sense that was a trick they used on A6 vs A8 4.2's. Might also be on air box/breathing side. That was used on C5 S6 vs. A6 4.2. Or, both. Look at where redline was for both too; if S8 higher, for HP it could most all be up near a higher redline. That was also true of C5 A6 vs. S6 4.2. BTW, I doubt torque would move much on an already well tuned N.A. motor (beyond S8 level that is), and if it did it would likely be at some expense to HP or overall meat of power curve.

The basic reason (other than S6 vs S8 deltas) you won't get much on N.A. motors is they tend already to be tuned by factory to get what they can and be smog legal--thus cam, ignition, cats, intake, all pretty optimized. If redline is shifted and valve timing played with (often torque for HP tradeoff there), and/or if it is a really tweaked manufacturer tuned intake and exhaust set up, or yet more compression, there can be some more to give. As in, R8 V10. Turbo's are by contrast always easy--just up the boost and get aggressive on the ignition timing/knock sensor/octane. Pay to play big time if pushed a lot and if/when they melt down of course.

Tangirz