Mccalist

Looking for some performance mods. Heard the best are exhaust and chips, and the best of these are the downpipes. Wondering if anyone knows of some, or has installed them and what their results were.

-Thanks

Jkay

As far as I have ever seen, only Cat-Back systems are available for the A/S8.

s eight

Thanks

Jkay

They connect the headers to the H-pipe. They point kinda down, from the engine to the undercarriage.

Jkay

To upgrade an exhaust, replacing one part is normally less than half the battle.

Our cars come with an H-pipe equalizer, which is great .. a lot more than most cars get! We can do better than this, tho, by replacing it with an X-pipe equalizer, which is a solid upgrade over an H-pipe.

Imagine a gentle flow of water inside your exhaust pipe; some of it follows the straight path along the main exhaust tube, and some flows thru the H-pipe equalizer, to use the 2nd main exhaust tube (dual exhaust, remember).

Now imagine that the water flow is not gentle, but moving at 600 miles per hour, ripping and raging down the main exhaust pipe. Do you think it wants to make a 90 degree, right angle TURN into an H-pipe? HELL NO. It wants to charge along in a straight line. H-pipe useless .. worse than useless. Dead weight.

With an X-pipe, the exhaust pulses are always channeled to share both main exhaust pipes. They can't force their way past it.

Our cars use 2 mufflers, in series. Can you say "backpressure"?? Sure they are whisper quiet, even at 6000 RPM but is that what you want? Many folks here have removed the 2nd muffler, and been pleased with the result, altho some think this is leaves the exhaust note too loud and droning.

It's generally agreed that removing the 1st muffler is a very bad idea because it does most of the silencing, and you're left with an exhaust note even louder than removing #2 muffler.

There are aftermarket exhaust systems which replace both mufflers, and all the pipes which come after the catalytic converters. These are ~$1400 USD. If you have that kind of cash laying around then by all means, find out which one you like best and buy it.

What's the definitive "best" setup for A/S8 owners who want a non-droning but sporty exhaust note? Get back to us when you find it.

One or two here are going to try installing an X-pipe and removing the 2nd muffler .. X-pipes soften and change the note .. maybe this combination is the magic one. We'll see.

Mccalist

Thanks for the info.

8 misbehavin

I would agree with the X vs. H pipe info, but disagree with the sound level resulting from removing the first muffler / resonator.

I removed the first muffler and ran straight pipes back from the dual cats to a Supersprint rear muffler. IMHO, it sounds fantastic (similar to a Mustang GT at idle and a bit more wild when you get on it!) and the only droning is when cruising at less than 2000 rpm. Not as much of an issue on the S8 versus my A8 due to gearing differences that tend to keep the S8 above that point anyway.

My .02. Good Luck.

S4_Got_Grip

Did anybody ever do this as stated...?

"One or two here are going to try installing an X-pipe and removing the 2nd muffler .. X-pipes soften and change the note .. maybe this combination is the magic one. We'll see."