3" Downpipe + 4" Exhaust in A4 Jetta

Fix_Until_Broke

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Aug 8, 2004
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Menomonee Falls, Wisconsin, USA
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03 Jetta, 03 TT TDI
Well - I'm not sure why I did it, but I did

Video - no muffler, stock everything else

Video - with muffler, PP502's & RC2. This much smoke is NOT typical, it had been 1000+ miles since anything over ~50% throttle (not to mention 100% as shown in the video) and there's a fair ammount to 'clean out'. The cloud from when I first pulled out of the driveway (can't see in the video - too far to the right) was embarrassingly large and black. Not quite enough to literally stop traffic like I could with my old 5.7L Diesel Regal, but more than acceptable for me Think IQ is a bit low (2-3 ish).

Video - With 4" Powerstroke muffler, 17/22 turbo, PP502's, RC6, VR6 MAF, 3" Turbo Inlet, etc - sounds like crap from the outside, but sounds nice and quiet inside which is where it counts for me.

I have no particular thing for the Aero Turbine muffler, I actually don't believe a lot of their claims on their website. It happens to be the only muffler that I found that would fit in the cat tunnel - that's the only reason I used it.

I had a cat + muffler ectomey's before but stock sizes. This was no louder in normal driving (in the cabin), moderately louder under throttle (in the cabin), nice turbo whistle (inside and out), moderately louder outside the car in all conditions. Video & Video of iBlake's car with the same setup (cat & muffler delete with stock sizes) for comparison.

[Now with muffler - these comments are for reference only] The 3"+4" straight pipe is a whole different story - it is slightly louder in normal driving (in the cabin) but has some resonances at certian speeds/loads, much louder under throttle (inside and out), crazy turbo whistle (outside), much louder outside the car in all conditions - probably borderline illegal. EDIT - this was primiarly while pulling a 1000 lb trailer, it is quieter with just the car - no louder under steady cruising conditions - EDIT

The turbo whistle sounds like a jet engine up to ~5 psi, then goes quiet above that. The jet engine sound is is present both on increasing and decreasing boost - think of a jet taxiing to the terminal. I really like this part of it. EDIT - this was tamed down a bit with the muffler, but not much - the muffler is a pretty decent high pass filter and the whistle comes through good, just quieter. - EDIT

There is (now was with muffler) definately a lot of ricer fart can sound to it, espically under load. I'll have to get a muffler in the future as I don't like the ppbbbttt sound and also have to get rid of the drones/resonances. I just hope it does not kill the turbo whistle. EDIT - Had to put a muffler in as the drones at 70+ MPH were too much for me. Muffler killed the ppbbbttt sound pretty much completely, but the turbo whistle didn't get hurt too badly. This should pass all but the most crotchety critics as far as noise/sound. - EDIT

EDIT - Deleted vibration comments, Vibrations fixed - EDIT


I know it's complete overkill, but if 4" fits, there's no reason to do 3" (big grin).

EDIT - EGT's with muffler are ~100F lower typically (on a stock nozzles/tune), 50-150 min/max reduction. A 3 mile 120 MPH WOT run turned out just at 900F post turbo EGT, previous runs gave a bit over 1000F. Both in similar ambient temperatures. Normal driving is also lower. Either the stock 2.25" system is restrictive or my EGT gauage shifted ~100F low.

Did a 2 mile top speed run (now with PP502's and RC2) and post turbo EGT's were ~1200F when I got out of it at 130 (both EGT's and MPH's still rising)

EMP measurements can be found in this thread and/or this thread

Still a couple little things I want to fix/adjust yet, but overall I'm very pleased with it. Will try to get some in cabin video/audio when I get the out side of car video with the muffler - EDIT

[/IMG]There (used to be) a muffler in here now between my foot and the flex joint where the cat used to be (it looks like this again). Will try to get pics sometime (looks like this now). - See post 145 for the latest setup - this ended up breaking right at the turbo flange





17FEB2008 - I finally got around to trying to get rid of the drone and ended up putting a 2nd muffler in. After 250+ miles, I think it's pretty much stock quiet now (which is really nice I must admit). I played around with 4-5 different tip arrangements and all it did was move the drone to another RPM or make it worse. The muffler is a 4" aftermarket one for a Powerstroke I think (8" OD x 24" Long). I pulled it back and up underneath the car so it is really inconspicous now. I've since painted it black instead of silver(ish) so you'd have to be looking for it to see it. I didn't mind the 4" tip (it definately raised some eyebrows and generated questions), but I really prefer the stealth look, and now sound as well. Pictures are not that good and the car is covered in salt (embarrassed).




EDIT - 07July2008 - In an effort to eliminate the very last rattle (in reverse under load like when backing a loaded trailer), I removed the AeroTurbine muffler and put a 4" pipe back in. So now it has the power stroke muffler in the OEM location only. It's a bit louder all around. Definately more coarse/throaty sound when on the throttle heavy, couple minor drones at higher revs, definately more turbo whistle. It's a touch louder when driving down the road on the cruise control and it's pulling a hill, but not enough for the significant other to notice. I might try and put the aero back in (needs to be ~1/2" lower) as I really liked the stock quiet sound, but will drive this for a while and see how it goes.

Side benefit of this is that the shutter that I've been fighting since the first of the year has all but disappeared!!! Not sure how/why, but when the muffler came out and the straight pipe went in, something is aligned/preloaded different and it is much better. This makes me think that I need more flex in the system, in all directions. I have the 3" bellows in the horizontal part (since it wouldn't fit in the downpipe) and I think I'll add more flex somewhere. Might try a piece of 4" flexible pipe like used on big trucks to see if it helps out before investing in a 4" bellows. - /EDIT The 4" flexible pipe is not flexible enough - it moves but you have to push it both ways unlike a bellows where you push it and it wants to come back to where it was

EDIT - 13 March 2010 - Must be getting older because the little drone/resonances I was getting at higher RPM's and under load while on the cruise control pulling a trailer were starting to bug me. I re-installed the 4040XL Aeroturbine muffler again in the OEM Cat location (like what's in the video above). The result is much quieter outside the car, a little quieter inside the car, drones are almost completely eliminated, pulling a trailer is much quieter, driving down the road is quieter as well. I might go out on a limb and say it's "OEM quiet"... No extra vibrations/rattles, etc which I was happy for. I'm using a longer 8" flex section (8" of actual flexable area) which I think helps as well as the flange on the turbo outlet which allows the engine to pivot and the exhaust to stay still which both should help vibrations and such. /EDIT

This made the drone worse


This worked really well at killing the drone, but I thought the requisite rain cap would have pushed it over the edge (wink).


This also got rid of the drone but was a touch more ricey than I was looking for
 
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Fix_Until_Broke

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Location
Menomonee Falls, Wisconsin, USA
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03 Jetta, 03 TT TDI
Did I mention that it's a cozy fit? And no - there is no putting it in a vice and flattening it.

Where it goes over the rear axle is near the pivot point, so that part of the axle only moves about 1/5 as far as the wheels do - that helps a lot. I had my trailer on it and was jumping on the coupling and couldn't make it hit the axle - must be far enough away?

After putting a 4" through there, I know I could get a 3" through there easily
 

Fix_Until_Broke

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Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
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03 Jetta, 03 TT TDI
I edited the first post with some more observations - not pulling a trailer this time. Either it's gotten better or I've gotten used to it. Probably some of both.

I've got a digital camcorder I'll dig out this weekend and try to get some video/audio. The big challange for me will be getting it from the camcorder to the internet. I'll take any suggestions on how to do it - I've got a JVC GR DVM75U. At a minimum I'll get some digital pics to tide you over :)
 

Ed's TDI

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'01 Bora and '97 A4 1.8T Quattro (future TDI conversion maybe?)
dabear95 said:
Envisions drinking a soda with a garden hose (thick) straw...


But hey, why not!


Jason
Nice comparison, but I was thinking more like trying to blow out a candle through a cardboard tube from a roll of paper towel.
 

Ed's TDI

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Joined
Jan 30, 2001
Location
Victoria, BC, Canada
TDI
'01 Bora and '97 A4 1.8T Quattro (future TDI conversion maybe?)
Fix_Until_Broke said:
I edited the first post with some more observations - not pulling a trailer this time. Either it's gotten better or I've gotten used to it. Probably some of both.

I've got a digital camcorder I'll dig out this weekend and try to get some video/audio. The big challange for me will be getting it from the camcorder to the internet. I'll take any suggestions on how to do it - I've got a JVC GR DVM75U. At a minimum I'll get some digital pics to tide you over :)
Post it up on Youtube.com
 

Fix_Until_Broke

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Joined
Aug 8, 2004
Location
Menomonee Falls, Wisconsin, USA
TDI
03 Jetta, 03 TT TDI
mannytranny said:
The stock exhaust size on the Duramax is 3.5 inches.......

FWIW
Yeah - 30% more pipe area, and 28% of the mass airflow, shouldn't be a problem:).

To put it in some perspective - I've always had a little puff of smoke on startup - about the size of a volleyball. With the stock size exhaust it was only a few tenths of a second. When I watched Al start it, it took almost a full second before the puff of smoke came out the exhaust after he started it:eek:.
 

Fix_Until_Broke

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03 Jetta, 03 TT TDI
Ed's TDI said:
Post it up on Youtube.com
Sorry - I needed to be a bit more specific. I need to get it from the camcorder to the computer - then I can give youtube a try or the TDIClub pics area. The camcorder has a USB connection, but that only works for digital pics stored on the SD card. The video is stored on 8mm tape. I think I'll "play" it on the television and record it with our DVR+DVD burner. I should then be able to take that DVD, put it in the computer and then upload it. Having never done any of this before - it may take me a few tries.
 

jasonTDI

TDI GURU Vendor , w/Business number
Joined
Apr 26, 2001
Location
Oregon, WI
TDI
12' RAM 2500 QC,LB. 2019 Cherokee 2.0T
I've heard it.

If that was the same one you had when you were at my place it's MEAN!
 

Fix_Until_Broke

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Location
Menomonee Falls, Wisconsin, USA
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03 Jetta, 03 TT TDI
Have I got a suprise for you....

jasonTDI said:
I've heard it.

If that was the same one you had when you were at my place it's MEAN!
What you heard was the stock size with muffler and cat delete.

If that's MEAN, then I don't know what this is, cruel? sadistic? angry woman? evil? An adjective fails me.
 

span1_85

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Jun 6, 2006
Location
Claymont, DE / Salem, NJ
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2002 Jetta TDI 5sp
holy cow.... a 4 incher thats amazing!!! where did u find that piping.. i'd be lucky enough to find and exhaust shop around here to mess with 3"....
 

greengeeker

Vendor
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Feb 8, 2006
Location
Cambridge, MN
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2002 Jetta GLS
Fix_Until_Broke said:
If that's MEAN, then I don't know what this is, cruel? sadistic? angry woman? evil? An adjective fails me.
Did you put these in order from bad to worst?

Look forward to the video.
 
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brew1

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Dec 18, 2004
Location
Richfield WI
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Sold 2003 Jetta Wagon 5 Speed
Fix_Until_Broke said:
What you heard was the stock size with muffler and cat delete.

If that's MEAN, then I don't know what this is, cruel? sadistic? angry woman? evil? An adjective fails me.
I went for a ride with your stock size decated/demufflered exhaust, not sure I would classify the sound as mean. A louder/deeper sound than normal under accleration, slightly louder while cruising and not even noticeable at idle. I'm looking forward to hearing the latest revision.
 

Fix_Until_Broke

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Menomonee Falls, Wisconsin, USA
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03 Jetta, 03 TT TDI
span1 85 said:
holy cow.... a 4 incher thats amazing!!! where did u find that piping.. i'd be lucky enough to find and exhaust shop around here to mess with 3"....
The pipe and mandrel bent elbows are easy to find in most any size. I did the work myself.

greengeeker said:
Did you put these in order from bad to worst?

Look forward to the video.
No - no particular order, just things that came to mind
If all goes well I'll have the video/audio this weekend

brew1 said:
I went for a ride with your stock size decated/demufflered exhaust, not sure I would classify the sound as mean. A louder/deeper sound than normal under accleration, slightly louder while cruising and not even noticeable at idle. I'm looking forward to hearing the latest revision.
jasonTDI heard it from the outside as I was pulling away with a 1000 lb trailer - probably sounds different than what you heard, especially inside the car.
 

Fix_Until_Broke

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Menomonee Falls, Wisconsin, USA
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03 Jetta, 03 TT TDI
How long does YouTube take to "process" the video? It's been out there for almost an hour - still "processing"....

Is there something I need to do?

greengeeker - I'm just learning this whole video thing. It was a short thing that would fit on the TDI pics page and I was just trying it out to see if it worked or not. Yes a picture would have done the same thing - that's why it was a tease
 

Slave2school

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Angus, Ontario
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99.5 used to at least...
Fix_Until_Broke said:
How long does YouTube take to "process" the video? It's been out there for almost an hour - still "processing"....

Is there something I need to do?

greengeeker - I'm just learning this whole video thing. It was a short thing that would fit on the TDI pics page and I was just trying it out to see if it worked or not. Yes a picture would have done the same thing - that's why it was a tease
mine took the better part of two hours to process and it was only 30 seconds long.
 

greengeeker

Vendor
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Feb 8, 2006
Location
Cambridge, MN
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2002 Jetta GLS
Fix_Until_Broke said:
I'm just learning this whole video thing. It was a short thing that would fit on the TDI pics page and I was just trying it out to see if it worked or not. Yes a picture would have done the same thing - that's why it was a tease
Sorry...didn't mean to come off that way. It's just that I get impatient sometimes. :eek:
 
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