My (ex) 3.0 A4 tip custom exhaust

B6 A4
#1

I don’t have this car anymore but I will try to share as much as I can about the 3.0 because I know how it felt to be left high and dry by the tuning companies.

So when I got this cusotm exhaust done, i didn;t really know as much as I know now about the proper diameter for this size motor. I used 2.5" but it might have been the right size to use to make up for the press bends. This system was made by trexturk on EA and AZ

Specs:
2.5" Aluminized steel piping - all press bends
2 12" generic louvered-core resonators
1 Magnaflow 2.5" x-pipe (the stamped one)
2 Magnaflow 14815 mufflers. They are 2.25" in with dual 3" straight cut outlets. trexturk later modified the tips to be staggered
1 B7 S4 valence glued onto the factory bumper

http://i183.photobucket.com/albums/x59/joec1992/IMG_2920.jpg

http://i183.photobucket.com/albums/x59/joec1992/IMG_2921.jpg

http://i183.photobucket.com/albums/x59/joec1992/IMG_2923.jpg

http://i183.photobucket.com/albums/x59/joec1992/IMG_2925.jpg

http://i183.photobucket.com/albums/x59/joec1992/IMG_2926.jpg

http://i183.photobucket.com/albums/x59/joec1992/IMG_3209.jpg

http://i183.photobucket.com/albums/x59/joec1992/photo-24.jpg

http://i183.photobucket.com/albums/x59/joec1992/IMG_4321.jpg

http://www.youtube.com/watch?v=cX7jHcO2gzY
http://www.youtube.com/watch?v=Jn4ibGD6bOo

When I decided to sell the car, I had to take the exhaust system off. I put a stock bumper on it before going to the exhaust shop, so the drive to the exhaust shop was quite loud. This is with the mufflers cut off - with the cuts being before the S bend just below the diff
http://www.youtube.com/watch?v=S5AeVL2Hq2E

#2

Thanks joe. This is what were looking for and that looks great.

Feel free to load some of those videos on here as well as some of the pictures, if you have a favorite or you have more.

I know texturk does great work maybe we can pull him into this and have him make DP’s for the 3.0.

#3

Nice system Joe. I was actually using your build to put together a similar system like yours.

With the X-pipe, where is the best place to actually install it (on our cars and the ideal place if you didnt have to worry about mechanical bits in the way)

#4

thanks for posting this over here Joe, I was planning on basically replicating your setup and didn’t want to have to dig through your old AZ threads to read up on it

#5

CountVohn - I will upload them to here if I still have the file on my computer.
Lout Jnr - The best place to install the x-pipe will always be as close to the headers as possible because the xpipe works more efficiently with hotter gasses. nothing mechanical really gets in the way
BCsniper - You had an A4 before too?

The mid-section with the xpipe and resonators is actually exactly what is on my S4 now.

I never posted power gains because I never dyno’d the car. But the butt dyno tells me I gained a lot of top end power and not really much of anything in the low end. Catless downpipes would REALLY wake the car up. The cats on this car are located where the precats are on an S4 but they are seriously twice the size. That was my next thing on my list but I found my S for too good of a deal to pass up.

#6

Count, can you see any reason that the 3.0 would need 2.5" pipes vs. 2.25"?
I’d prefer to get 2.25" to lessen the volume of the exhaust a little bit and get rid of some of the drone, bt do you think that having a 2.25" pipes would hold back the 3.0 any like it does on the 4.2

Joe, my S4 is gone, Joey chopped it up and parted it out the moment he got it (would have been nice if he told me that was the plan…)
I bought a 3.0 6MT Avant to replace the disaster-prone 4.2
Now I just have 2 V6 Audi’s in the driveway…my new 3.0 Avant and my old car a 2.8 C5 A6 that is my brothers car

#7

2.25" would probably work just fine for basic improvments power wise, it’s not an 8 and is not running tremendous amounts of power (yet) . With the addition of SC, TT any major power addition 2.50 will still be plenty.

So no the .25 to the .50 is not going to hinder the power to much as long as its a smooth flowing nonrestrictive system. The pictures of the one on this post would work great and you can even improve the x by using the same type from the JHM RS4 system.

#8

Flow wise the math isn’t there for the need of a 2.5. The 2.25 has more then enough volume.

The noise level of almost any exhaust is a byproduct of proper or improper ballence and design. Drone is also a byproduct of a poor built exhaust. My A6 with a 4.2 S8 motor has the loudest exhaust your going to hear. However there is no drone and the cabon noise is very low.

Placement and angles of entry into and out of the X. The placement of the X and several other factors are going to play a large roll in drone. The 2.75" JHM Rs4 exhaust is softer at iddle then the 2.3" Milltek, has less drone (Almost none) and it obviously flows better. So its the design of the exhaust more so then the size.

#9

Awesome, I’ve heard theories supporting both sides. This one made more sense, glad to have it confirmed. With that in mind, I think we need to figure out how much (or how little) modification needs to be made to the stock exhaust. As they apparently don’t have precats I’m not sure how we can get around making the stock one flow better while still being able to pass emissions.

#10

the best spot tends to be almost immediately after the end of the downpipes. Thankfully the quattro undercarriage is pretty smooth and lets you place it anywhere.

[quote=“B6JoeS4,post:5,topic:2727”]
well there is also the issue with the tuning of the standing waves. A longer distance from the start of the secondary to the crossover increases the size of the standing wave, decreasing the frequency. A lower frequency results in the pulse tuning at lower engine speeds. So long story short, the closer the crossover is the better it helps scavenge at higher engine speeds.

[quote=“B6JoeS4,post:5,topic:2727”]
In which dimension are they bigger? Are they longer, or bigger around?

Agreed, dual 2.50 is plenty for the stock motor 8’s I bet 2.25" will be fine for the stock motor 6’s. Also, I believe the 6’s may not rev as high (not sure though), which means the smaller pipe will do fine.

Also x2 on the RS4 style X-pipe. I’ve had a similar piece in 2.5" on my S4 an A6 4.2, and I know quite a few guys on here have the same smaller piece and its fantastic.

You get headers on that one yet? haha, I’ll take my mid pipes out and beat you on the exhaust loudness competition.

Sniff test emissions, or OBDII emissions? The OBDII can be tricked in the tune, the sniff test can be taken care of by building a building a two piece downpipe with a flanged lower high flow cat/test pipe section that could be easily swapped in or out.

#11

OBDII, they just plug it in for a minute, I just had mine done so I’m OK for 2 years anyways. That being said I am not a huge fan of test pipes and the smell and noise associated with them, which is why I wanted to go HFC, and in consideration for people who do have to deal with emissions. The only option I’ve found for our cars is labree’s stuff, which is $1000 for a pair. I think we need to figure out a solution similar to the piggies… but then we also need to figure out if downpipes are going to be beneficial.

#12

Lol at joey parting people cars without them knowing before hand. He did that to a perfectly running full JHM Nogaro Avant…

Another thing about the whole 2.25 vs 2.5…the 2.5 droned a lot at any speed. At the end of a day of driving, i wanted to kill a baby. I drove to Delaware and back (from Chicago) and I wanted to just sew my ears shut.

Both. They are about 8" in diameter and probably 10-13" long. Bigger than the cat on the 1.8 by a lot

#13

Do you have any pictures you can post of these downpipes on or off the car.

#14

No i don’t unfortunately

#15

damn, well bigger around with the cat matrix in there is good since it’ll flow more but longer is bad because there will be more pressure drop. With it being that size though, the whole chamber should be removed if doing piggies… which kind of suggests to me some new pipes would be a better bet.

#16

Was trying to post some pictures of the stock 4.2 DP’s for a refrence to the giant 3.0 cats but no luck.

Does seem possible to use the same type of cat used on the 4.2 jhm system to replace the stock monster for the 3.0 just down grade the size to a 2.5 so that there is no flow issues.
This is a possible easy solution.

Comments please

#17

Hopefully this pic can shed some light on this area

http://audirevolution.net/addons/albums/images/209957516.jpg

I can try and get measurements if you need, let me know if you would like to see a different angle.

#18

Here is a basic MS paint diagram of the 3.0 cat as I remember it. Notice how the pipe leaving the cat actually comes out of the bottom section.

http://i183.photobucket.com/albums/x59/joec1992/30cat.png

#19

Picture helps a little and if the drawing is correct wow thats gonna get changed period…

#20

that is some first rate ms-paint work right there… that exit out of the cat can’t be good for anything power related.

lount jr. - do you have any pictures of the downpipes out of the car? if not, maybe we could get a shot from below the motor looking at how the pipes go up? once again, great pictures.