With all this talk of Downpipes lately, it seems there is a lot of confusion...

ryans4 · 03-11-2002, 02:59 PM

After reading this post

It seems that lots of people don't know much about what each downpipe kit offers.

I've been collecting information (pre-purchase research) and this is what I've found so far.

***Any corrections to my information are appreciated.***

I just want to have everyone on the same page.

I've put each option against a list of features that seem to cover a portion of each aftermarket downpipe system.

Those features are:

1. Increased pipe diameter over stock?
2. Removal of Pre-Cats?
3. O2 sensor location fore and after cat?
(this will allow ANY ECU to run with the downpipes)
4. Test-Pipe Option?
5. Flex Joints?
6. Cat Type
7. Cost?

So now how does each option (that I'm aware of) stack up?

Stock System
Diameter = <2.25" (I believe)
Pre-Cats = YES
O2 Sensor location fore and aft of cats = YES
Test Pipes = NO
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = Pre = Metal, Main = Ceramic
Cost = Nothing, you already have them.

APR
Diameter = 2.5" (I believe)
Pre-Cats = NO
O2 Sensor location fore and aft of cats = NO
Test Pipes = YES
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = ?
Cost = $1600

AWE
Diameter = taper from 3" to 2.5"
Pre-Cats = NO
02 Sensor location fore and aft of cats = YES
Test Pipes = YES
Flex Joints = YES (ball/socket joint)
Cat Type = 400 cell per inch Ceramic Matrix
Cost = $1595

JP Engineering
Diameter = taper from 3" to 2.5"
Pre-Cats = NO
O2 Sensor location fore and aft of cats = YES
Test Pipes = NO
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = Carsound (400cpi Ceramic)
Cost = $1350

Milltek
Diameter = 2.3" (60mm)
Pre-Cats = NO
O2 Sensor Location fore and aft of cats = They say YES, but it doesn't look like it from the PICS. But we'll go with YES since they claim it.
Test Pipes = NO
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = continuous stainless steel cores
Cost = $1865

MTM
Diameter = ?
Pre-Cats = NO
O2 Sensor location fore and aft of cats = ?
Test Pipes = ?
Flex Joints = YES (not sure what type)
Cat Type = ?
Cost = $6900 (part of there Stage 3 package)

RS4
Diameter = ?
Pre-Cats = YES
O2 Sensor location fore and aft of cats = YES
Test Pipes = NO
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = ?
Cost = $3000
(cost is from this post

That about sums it up.

Corrections are encouraged (after all, we should all know the right information).

I'm not trying to start a war (or am I?), just trying to get the cold hard numbers.

Can one of you RS4 downpipe junkies post information about the pipes, I know nothing about these.

FWIW...

Todd/A.W.E. · 03-11-2002, 03:29 PM

Milltek: no test pipes (those pipes in the pics are to mate to exhaust system. Makes them universal to the RS4, too, I think)

MTM: no pre-cats.

Carsound cats are 400 cell ceramic, too.

Scourge · 03-11-2002, 03:31 PM

before and after cats and hence needed a chip before...

ryans4 · 03-11-2002, 03:31 PM

ryans4 · 03-11-2002, 03:32 PM

But if you run Test Pipes you need an ECU that can understand you now have NO cats.

KAOS, AZ (Papa Smurf) · 03-11-2002, 03:34 PM

LCP · 03-11-2002, 03:39 PM

Scourge · 03-11-2002, 03:42 PM

take a look at Todds post
http://forums.audiworld.com/s4/msgs/465188.phtml

AWE dp's DO require a recoded chip...

"The improved flow allowed us to increase upper rpm boost, while requiring us to adjust fueling a bit higher. We believe that a properly tuned downpipe system *requires* the use of a specific downpipe chip if the downpipes are doing their job of improving exhaust scavenging. Our design requires a change to the O2 sensor coding, too, as we opted to place the O2 sensors close to the OEM position to maintain proper tension on the wiring.
"

ryans4 · 03-11-2002, 03:47 PM

That if the O2 sensors are Pre and Post the cat, then they are still registering the delta, and thus still work.

As for Todd's statement, I'm sure that a proper ECU that takes full advantage of the change in exhaust flow is a bonus to the system.

Perhaps Todd/AWE can comment more on this?

ryans4 · 03-11-2002, 03:48 PM

03-11-2002, 02:59 PM	#1
ryans4 Senior Member Account #: 4359 Join Date: Apr 2000 Posts: 7,314	With all this talk of Downpipes lately, it seems there is a lot of confusion... After reading this post It seems that lots of people don't know much about what each downpipe kit offers. I've been collecting information (pre-purchase research) and this is what I've found so far. *Any corrections to my information are appreciated.* I just want to have everyone on the same page. I've put each option against a list of features that seem to cover a portion of each aftermarket downpipe system. Those features are: 1. Increased pipe diameter over stock? 2. Removal of Pre-Cats? 3. O2 sensor location fore and after cat? (this will allow ANY ECU to run with the downpipes) 4. Test-Pipe Option? 5. Flex Joints? 6. Cat Type 7. Cost? So now how does each option (that I'm aware of) stack up? Stock System Diameter = <2.25" (I believe) Pre-Cats = YES O2 Sensor location fore and aft of cats = YES Test Pipes = NO Flex Joints = YES (metal mesh/bellows-type) Cat Type = Pre = Metal, Main = Ceramic Cost = Nothing, you already have them. APR Diameter = 2.5" (I believe) Pre-Cats = NO O2 Sensor location fore and aft of cats = NO Test Pipes = YES Flex Joints = YES (metal mesh/bellows-type) Cat Type = ? Cost = $1600 AWE Diameter = taper from 3" to 2.5" Pre-Cats = NO 02 Sensor location fore and aft of cats = YES Test Pipes = YES Flex Joints = YES (ball/socket joint) Cat Type = 400 cell per inch Ceramic Matrix Cost = $1595 JP Engineering Diameter = taper from 3" to 2.5" Pre-Cats = NO O2 Sensor location fore and aft of cats = YES Test Pipes = NO Flex Joints = YES (metal mesh/bellows-type) Cat Type = Carsound (400cpi Ceramic) Cost = $1350 Milltek Diameter = 2.3" (60mm) Pre-Cats = NO O2 Sensor Location fore and aft of cats = They say YES, but it doesn't look like it from the PICS. But we'll go with YES since they claim it. Test Pipes = NO Flex Joints = YES (metal mesh/bellows-type) Cat Type = continuous stainless steel cores Cost = $1865 MTM Diameter = ? Pre-Cats = NO O2 Sensor location fore and aft of cats = ? Test Pipes = ? Flex Joints = YES (not sure what type) Cat Type = ? Cost = $6900 (part of there Stage 3 package) RS4 Diameter = ? Pre-Cats = YES O2 Sensor location fore and aft of cats = YES Test Pipes = NO Flex Joints = YES (metal mesh/bellows-type) Cat Type = ? Cost = $3000 (cost is from this post That about sums it up. Corrections are encouraged (after all, we should all know the right information). I'm not trying to start a war (or am I?), just trying to get the cold hard numbers. Can one of you RS4 downpipe junkies post information about the pipes, I know nothing about these. FWIW... __________________

03-11-2002, 03:29 PM	#2
Todd/A.W.E. Member Account #: 1150 Join Date: Mar 2000 Posts: 4,109	Corrections: Milltek: no test pipes (those pipes in the pics are to mate to exhaust system. Makes them universal to the RS4, too, I think) MTM: no pre-cats. Carsound cats are 400 cell ceramic, too. __________________ Todd Sager President A.W.E. Tuning Order line: 1-888-565-2257 Tech line: 215-658-1670

03-11-2002, 03:31 PM	#3
Scourge Junior Member Account #: 15242 Join Date: Jan 2001 Posts: 504	Is there anything different on AWE dp's now? They did not have o2 sensors ... before and after cats and hence needed a chip before...

03-11-2002, 03:31 PM	#4
ryans4 Senior Member Account #: 4359 Join Date: Apr 2000 Posts: 7,314	thanks...i edited my post. __________________

03-11-2002, 03:32 PM	#5
ryans4 Senior Member Account #: 4359 Join Date: Apr 2000 Posts: 7,314	I never heard that. AWE always had the O2 sensor moved... But if you run Test Pipes you need an ECU that can understand you now have NO cats. __________________

03-11-2002, 03:34 PM	#6
KAOS, AZ (Papa Smurf) Member Account #: 1134 Join Date: Mar 2000 Posts: 3,237	nope, disagree __________________ EVERYTHING POSTED HERE BY ME IS OF PERSONAL OPINION

03-11-2002, 03:39 PM	#7
LCP AudiWorld Expert Account #: 125 Join Date: Mar 2000 Posts: 26,557	*Stock cats are ceramic (main), metal (pre), and I think* a tad less than 2.25"** __________________ "I can't stop apexing" 2000 S4 :: Nogaro Blue :: 6-spd :: AWE RSK04 :: AP Racing 13" 4-pots STaSIS Tracksports 550f/600r + 19mm rear sway bar :: APR Bipipe RS4 ICs :: Forge BPVs :: Autospeed DPs :: Borla :: Aquamist 1s UUC 40% short shifter w/spacer mod :: AWE center vent boost guage Lightweight flywheel :: 18x8 Ronal LZ's :: 235/40-18 Toyo T1R's 2002 allroad :: Atlas Grey :: Tip :: 245/50-17 Dunlop SP5000's Looking for tires? See My review of all of the tires I've had on my S4 Need info? See Everything anyone needs to know about their S4 Help our troops protect their heads: Donate to Operation Helmet Rest In Peace Matthew Ammon a/k/a O.W. Kenobi. May the Force be with you as you keep on apexing. Read his funniest post here.

03-11-2002, 03:42 PM	#8
Scourge Junior Member Account #: 15242 Join Date: Jan 2001 Posts: 504	Well... take a look at Todds post http://forums.audiworld.com/s4/msgs/465188.phtml AWE dp's DO require a recoded chip... "The improved flow allowed us to increase upper rpm boost, while requiring us to adjust fueling a bit higher. We believe that a properly tuned downpipe system requires the use of a specific downpipe chip if the downpipes are doing their job of improving exhaust scavenging. Our design requires a change to the O2 sensor coding, too, as we opted to place the O2 sensors close to the OEM position to maintain proper tension on the wiring. "

03-11-2002, 03:47 PM	#9
ryans4 Senior Member Account #: 4359 Join Date: Apr 2000 Posts: 7,314	Interesting...my thoughts are... That if the O2 sensors are Pre and Post the cat, then they are still registering the delta, and thus still work. As for Todd's statement, I'm sure that a proper ECU that takes full advantage of the change in exhaust flow is a bonus to the system. Perhaps Todd/AWE can comment more on this? __________________

03-11-2002, 03:48 PM	#10
ryans4 Senior Member Account #: 4359 Join Date: Apr 2000 Posts: 7,314	thanks...updated the post. __________________

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