Can someone clear this up for me

[Coors]

Alright, I've been doing mad research for my new exhaust set-up. I still have some questions, hopefully someone can help me.

I have been reading about deleteing or not deleting resonators and an X-pipes.

Is the X-pipe and resonator the same?

My question is this...

The downpipes contain the pre-cats (which Vast guts) ok, I got that, and then immediatley after the flex joints are the main cats? Correct?

From looking under the car I see the downpipes, which go into the X-pipe then back to the mufflers. So, where are the resonators?

Thanks
E

[390wheel]

what engine is it???

[Coors]

An X pipe connects the two pipes downstream into the shape of an X, its supposed to increase exhaust flow. I haven't seen one on an audi before, just mustangs, camaros etc.
The resonator is like a second muffler which is before the back muffler. If you want to get any sound out of your car, you have to either upgrade or remove the stock resonator. The best sound would be to eliminate the resonator and using a custom muffler set up.

Above, compliments of AudiTech79 from AF

[Stampy]

I never understood why people add an Xpipe. Why would you want to create more turbulence for the flow? Wouldn't you want a straight through design like it comes with?

[wofman]

Coors - if I recall you have the 2.7 (did you get S4 rims?). So you don't want x pipes and unless car was modded you don't have them (what you saw was not an x -- edges of separate pipes come close together after downpipes, but pipes are separate all the way back from turbos): dual exhaust. Resonators are the first "muffler" portions in the catback section. If you don't see any resonators (approx under back seat floor area) then your car was modded

You're correct about the rest -- Precats are right after turbos (first part of downpipes) and then the Cats are in the wider, expanded section of OEM downpipes.

[wofman]

"...helpful and well respected...."

just like Hoffy!

[Coors]

Coors - if I recall you have the 2.7 (did you get S4 rims?). So you don't want x pipes and unless car was modded you don't have them (what you saw was not an x -- edges of separate pipes come close together after downpipes, but pipes are separate all the way back from turbos): dual exhaust. Resonators are the first "muffler" portions in the catback section. If you don't see any resonators (approx under back seat floor area) then your car was modded

You're correct about the rest -- Precats are right after turbos (first part of downpipes) and then the Cats are in the wider, expanded section of OEM downpipes.

Hey man, no go on the S4's rims. I was to late to the party. Still on the look out for a good deal though.

Almost positive its a stock system minus the piggies. Either way I gues I'll go straight pipe from cats back to mufflers and keep the "sleeper" tips hidden.

You still happy with your Milltek set-up?

[HOFFY11]

just like Hoffy!

stop being so mean

[Kievskiy]

if the x-pipe is done correctly, sizewise, it gives a nice r32ish/b5/rs4ish sound ;) matter of the sound, personally don't like how c5 2.7t sounds with straight piping, i had both.

[RS6-4dr911]

The purpose of x-pipes, as I understand it, is to smooth out the flow of the exhaust, not to create turbulence. Turbulence is generally bad in exhaust and generally good in intakes. With a V configuration, the banks are firing alternately so while one regular pipe has an exhaust pulse going through it, the other is in between pulses. The x-pipe takes advantage of this and lets the lower pressure side carry some of the "load". Once the exhaust pulse hits the x, it has 2 routes to escape instead of just one. With a turbo, the pulses are already smoothed out after having gone through the turbine and so there is little benefit. Anyone who knows better feel free to chime in.

[slim26]

Once the exhaust pulse hits the x, it has 2 routes to escape instead of just one.

that makes sense, never thought about it that way

[wofman]

last post is essentially right, except they are more than smoothed -- they are sent spiraling with force, so x-pipe = collisions

btw, the collisions presumably entail some noise cancellation effects as well, which some folks seem to like; from performance point of view I'd think it's a poor idea

[Stampy]

Yep, the main reason I know people do it is for sound. If I had a 2.7T, no way in hell I would consider one.

[Kievskiy]

2.7T is a tricky engine, and any exhaust set up xpipe or not wont give you a lot/anything unless you have a set of downpipes, after that, it opens up, i put my xpipe because without it it sounded like a NA v6 with mufflers, and i liked the sound of the r32 when i heard it, and like i said before xpipe can be made differently, and the size of the xpipe actually is the point when your performance will get worth or stay the same giving you that nice crispy sound, but i wont get better.
And as always we will have a lot of opinions about do it or not, but everyone wants his car to sound nice, only difference is, we like different sounds ;)
peace

[ckpepper02]

Hey Andrey,

i saw your youtube posts and I like they way your car sounds. Do you have a youtube with your car without the xpipe for comparison?

[Kievskiy]

nope, i wish i had.....:(

[Coors]

Decided to go with magnaflow's #12225 (5x8 ovals, 2.25", offset/center)
Going to delete center muffler/res. and striaght pipe 2.25" piping from cats back to the mufflers.

From reading countless threads and watching video after video, I came to the conculsion that ovals are a little more conservative then the 4"-6" round coffee can mufflers.

I hope it is not going to be to obnoxious. I have the 6spd, so hoping it does not have that back fire or popping sound when under load and going through gears.

We"ll see!

[oc-drop]

hope you're not keeping the stock cats =)

[wofman]

Decided to go with magnaflow's #12225 (5x8 ovals, 2.25", offset/center)
Going to delete center muffler/res. and striaght pipe 2.25" piping from cats back to the mufflers.

From reading countless threads and watching video after video, I came to the conculsion that ovals are a little more conservative then the 4"-6" round coffee can mufflers.

I hope it is not going to be to obnoxious. I have the 6spd, so hoping it does not have that back fire or popping sound when under load and going through gears.

We"ll see!

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Ovals should work -- 18" on mufflers? what are you doing with downpipes?

[Coors]

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Ovals should work -- 18" on mufflers? what are you doing with downpipes?

I have piggies already. Been running them since I got the GIAC, last March

Wofman, not sure what you mean by --18" on mufflers ??

the 5 x 8 ovals measure 14" X 20"

What do you think of this set-up? I would have loved to have went with your set-up but...$$$

[Kievskiy]

here is the video i found of my 6 w/o x-pipe and no downpipes installed.
http://video.google.com/videosearch?...0&oq=a6+in+sn#

[wofman]

I have piggies already. Been running them since I got the GIAC, last March

Wofman, not sure what you mean by --18" on mufflers ??

the 5 x 8 ovals measure 14" X 20"

What do you think of this set-up? I would have loved to have went with your set-up but...$$$

I meant, are the 5x8 ovals 18" long? I suspect you'll like what you're putting in. I was looking at similar, but with resonators (I think I was going to do 4" round, 12 or 14 L, and 5x8 ovals, 18 L. Most folks here want more sound than I do, so you may be about where you want. Can always add resonators with custom set-up. VAST downpipes and simple, dual catback will be good for power.

What year do you have? Tips thru valence or downturn?

[ckpepper02]

here is the video i found of my 6 w/o x-pipe and no downpipes installed.
http://video.google.com/videosearch?...0&oq=a6+in+sn#

errr.... Is that you drifting in the snow? If so, the music it too loud to hear the exhaust.

[Coors]

What year do you have? Tips thru valence or downturn?

I have an '2001 with the hidden downturn tips. I gave this alot of thought as well. I have read so much about exhaust set-ups over the last couple of days my brain is fried.

I knew that I wanted a system that I could easily and cleanly remove if ever decided to go stock again. I am keeping my stock set-up just in case I ever decide to put it back in.

So, cutting the valence would not be a wise choice if I decide to go back to stock. I would have cutouts and no tips.

Well, then again, I could always add tips to the stock system.

I can always do this down the road. I would like to have some oval tips or the newer Porsche 996 Turbo's tips.

[wofman]

[QUOTE=Coors;3168524]
...Well, then again, I could always add tips to the stock system.
I can always do this down the road. I would like to have some oval tips or the newer Porsche 996 Turbo's tips.

--------
Adding tips is silly easy. I was going to do oval tips, too. I like regular ovals better than the alternative -- maybe 3x4 ish or so?

[Kievskiy]

Shit, sorry man, that is the wrong link and music
here it is:
http://video.google.com/videoplay?do...udi+drift+snow

errr.... Is that you drifting in the snow? If so, the music it too loud to hear the exhaust.

[Stone825]

Don't flame me but would these fit well in the A6?
http://www.mufflermall.com/index.php...22f44f914a0950

And how easy would they be to install / remove?

[ckpepper02]

Shit, sorry man, that is the wrong link and music
here it is:
http://video.google.com/videoplay?do...udi+drift+snow

Now that's much better! LOL

I like that sound best. Is that with straight pipes? Did you have your piggies then? Which mufflers did you have?

[ENDEE666]

After hearing many say I should not have an X pipe, I removed mine a while back. Sounded like ass. Reminded me of a V6 Camaro or any other GM V6. Sounded awful so I put it back in, after wasting money to remove it and put it back. Search any of my posts on exhausts for more info. Mine is super quiet when cruising, supercar-ish tuned scream when full throttle. All my mufflers are straight thru and there is no cats at all. So flow is fine. Anyone who says my exhaust is 'restrictive' should remember I have the only A6 in the 11's. If you want quiet, do my setup. All 4 of my mufflers are 18" long so they quiet it a lot. I expect that if I removed my mid-mufflers (resonators) I would end up with a sound like Kievsky since the rest is very similar. His exhaust is by far my favorite, but using the car for business & wanting a sleeper keeps me quieter.

[ENDEE666]

Oh, and power wise, the X pipe made the mid range power better and more of a burst. I felt no increase without it, only the small decrease at 3-5k rpm.

Also remember, that from one free flowing exhaust to another there will rarely be mind blowing power differences. Anything is better than stock if you stay 2.5" and straight thru mufflers.

[Kievskiy]

Stock Downpipes, no resonators, straight to the mufflers.
Here how it was under the car:

Now that's much better! LOL

I like that sound best. Is that with straight pipes? Did you have your piggies then? Which mufflers did you have?

[wofman]

Oh, and power wise, the X pipe made the mid range power better and more of a burst. I felt no increase without it, only the small decrease at 3-5k rpm.

Also remember, that from one free flowing exhaust to another there will rarely be mind blowing power differences. Anything is better than stock if you stay 2.5" and straight thru mufflers.

I think your 2nd point is probably on target here -- we're talking catbacks after turbos and free-flow downpipes; not much impact to be had. As for x-pipes increasing power, my understanding is that is impossible. (Might help a tad on naturally aspirated?) "Noise cancellation" (sound waves filling troughs when colliding) effects must be the part of the x-pipe recipe that you folks like.