Downpipes: Revisited - Looking to update this FAQ started by RyanS4? (tuners please correct)

SmokinS4™ · 08-20-2003, 11:13 AM

1. Inner Diameter
2. Removal of Pre-Cats?
3. O2 sensor location fore and after cat? (if cats are doing their job, you won't get a CEL. Some tuners also will reprogram the chip to ignore this code too - ie test-pipe option-chips)
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 400cel
Cost = Nothing, you already have them.

<b> Piggie Pipes - OEM with gutted precats</b>
<a href="http://www.vastperformance.com/products/exhaust.php">Piggie Pipes</a>
Diameter = <2.25" (I believe)
Pre-Cats = Not anymore
O2 Sensor location fore and aft of cats = YES, often relocated 2nd O2 sensor to behind main cat
Test Pipes = NO
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = Main = Ceramic 400cel
Cost = stockers plus labor.
<img src="http://www.vastperformance.com/images/piggies_web.jpg">

APR
Diameter = 3.0"
Pre-Cats = NO
O2 Sensor location fore and aft of cats = YES
Test Pipes = YES
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = ?
Cost = $1499

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
ANYONE HAVE A PIC?

Milltek
Diameter = 2.3" (60mm)
Pre-Cats = NO
O2 Sensor Location fore and aft of cats = YES
Test Pipes = NO
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = continuous stainless steel cores 200cel
Cost = $1865

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

RS4
Diameter = 2.3inch inner 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 = Precat-precious metal, main cat=ceramic 400cel
Cost = $3000 or $1200 used.

Tantrumwerks Split Downpipes
Diameter = merge into a 2.5" pipe
Pre-Cats = NO
O2 Sensor location fore and aft of cats = YES
Test Pipes = yes
Flex Joints = YES (metal mesh/bellows-type)
Cat Type = ???
Cost = $1550 for stainless w/cats (other options available)
other note: divorced wastegate downpipes

Autospeed
Diameter = 3.0inch, tapers to 2.5 for most aftermarket cat-back exhausts
Pre-Cats = NO
O2 Sensor location fore and aft of cats = YES
Test Pipes = YES
Flex Joints = 3" Stainless Steel Braided Flex Joint.
Cat Type = 400cel ceramic cats
Cost = $1549.

GHL Downpipes
Diameter = 2.5
Pre-Cats = NO
O2 Sensor location fore and aft of cats = YES
Test Pipes = YES
Flex Joints = 3" Stainless Steel Braided Flex Joint.
Cat Type = ???
Cost = $1279

http://forums.audiworld.com/s4/msgs/718930.phtml

LCP · 08-20-2003, 11:24 AM

SmokinS4™ · 08-20-2003, 11:38 AM

Chaka · 08-20-2003, 11:45 AM

Even if you have the sensors located before and after you can still get a check engine light if your cats are inefficient.

SmokinS4™ · 08-20-2003, 11:52 AM

I edited the wording a little....better?

S4mig@PEB tuning · 08-20-2003, 11:59 AM

and

by the looks its a 1 1/2 and a 1 3/4 that dumps into a 3 inch pipe.

DAP@EPL · 08-20-2003, 12:17 PM

and a 3" inlet. Check out Mark P's pictures.

-Dave Pramanik

http://ctny.audiworld.com/mark/s4/downpipes/

~~Mike@VAST~~ · 08-20-2003, 12:19 PM

SmokinS4™ · 08-20-2003, 12:38 PM

SmokinS4™ · 08-20-2003, 12:38 PM

08-20-2003, 11:13 AM	#1
SmokinS4™ AudiWorld Super User Account #: 18942 Join Date: Apr 2001 Posts: 10,504	Downpipes: Revisited - Looking to update this FAQ started by RyanS4? (tuners please correct) 1. Inner Diameter 2. Removal of Pre-Cats? 3. O2 sensor location fore and after cat? (if cats are doing their job, you won't get a CEL. Some tuners also will reprogram the chip to ignore this code too - ie test-pipe option-chips) 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 400cel Cost = Nothing, you already have them. <b> Piggie Pipes - OEM with gutted precats</b> <a href="http://www.vastperformance.com/products/exhaust.php">Piggie Pipes</a> Diameter = <2.25" (I believe) Pre-Cats = Not anymore O2 Sensor location fore and aft of cats = YES, often relocated 2nd O2 sensor to behind main cat Test Pipes = NO Flex Joints = YES (metal mesh/bellows-type) Cat Type = Main = Ceramic 400cel Cost = stockers plus labor. <img src="http://www.vastperformance.com/images/piggies_web.jpg"> APR Diameter = 3.0" Pre-Cats = NO O2 Sensor location fore and aft of cats = YES Test Pipes = YES Flex Joints = YES (metal mesh/bellows-type) Cat Type = ? Cost = $1499 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 ANYONE HAVE A PIC? Milltek Diameter = 2.3" (60mm) Pre-Cats = NO O2 Sensor Location fore and aft of cats = YES Test Pipes = NO Flex Joints = YES (metal mesh/bellows-type) Cat Type = continuous stainless steel cores 200cel Cost = $1865 MTM Diameter = ? Pre-Cats = NO O2 Sensor location fore and aft of cats = YES Test Pipes = ? Flex Joints = YES (not sure what type) Cat Type = ? Cost = $6900 (part of there Stage 3 package) RS4 Diameter = 2.3inch inner 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 = Precat-precious metal, main cat=ceramic 400cel Cost = $3000 or $1200 used. Tantrumwerks Split Downpipes Diameter = merge into a 2.5" pipe Pre-Cats = NO O2 Sensor location fore and aft of cats = YES Test Pipes = yes Flex Joints = YES (metal mesh/bellows-type) Cat Type = ??? Cost = $1550 for stainless w/cats (other options available) other note: divorced wastegate downpipes Autospeed Diameter = 3.0inch, tapers to 2.5 for most aftermarket cat-back exhausts Pre-Cats = NO O2 Sensor location fore and aft of cats = YES Test Pipes = YES Flex Joints = 3" Stainless Steel Braided Flex Joint. Cat Type = 400cel ceramic cats Cost = $1549. GHL Downpipes Diameter = 2.5 Pre-Cats = NO O2 Sensor location fore and aft of cats = YES Test Pipes = YES Flex Joints = 3" Stainless Steel Braided Flex Joint. Cat Type = ??? Cost = $1279 http://forums.audiworld.com/s4/msgs/718930.phtml __________________ ------------------------------------------- -------------------------------------------- how's that for a short signature Stg4 S4.

08-20-2003, 11:24 AM	#2
LCP AudiWorld Expert Account #: 125 Join Date: Mar 2000 Posts: 26,557	Autospeed DPs have ceramic cats __________________ "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.

08-20-2003, 11:38 AM	#3
SmokinS4™ AudiWorld Super User Account #: 18942 Join Date: Apr 2001 Posts: 10,504	Thanks, updated. I would like confirmation on APRs, since I think they've gone thru some revision. __________________ ------------------------------------------- -------------------------------------------- how's that for a short signature Stg4 S4.

08-20-2003, 11:45 AM	#4
Chaka AudiWorld Super User Account #: 4863 Join Date: May 2000 Posts: 7,698	#3 is not generally correct Even if you have the sensors located before and after you can still get a check engine light if your cats are inefficient. __________________

08-20-2003, 11:52 AM	#5
SmokinS4™ AudiWorld Super User Account #: 18942 Join Date: Apr 2001 Posts: 10,504	Yup, I was using his as a baseline (cut and paste) I edited the wording a little....better? __________________ ------------------------------------------- -------------------------------------------- how's that for a short signature Stg4 S4.

08-20-2003, 11:59 AM	#6
S4mig@PEB tuning Elder Member Account #: 54947 Join Date: Apr 2003 Posts: 12,903	About the tantrumwerks DP's and by the looks its a 1 1/2 and a 1 3/4 that dumps into a 3 inch pipe. __________________ <a href="http://account.audiworld.com/users/20137.phtml"> </a> AIM: aSmig4 My favorite "tuner" quote, now deleted: "If you had purchased our kit you car would still be a nice 2002 S4 instead of a big pile of blue garbage." Bob@strat. describing BuffaloNogaro's car. Do tuners lie? FOD kills.

08-20-2003, 12:17 PM	#7
DAP@EPL Audiworld Sponsor Account #: 6924 Join Date: Jun 2000 Posts: 19,701	APR's new downpipes do have relocated O2 sensor ports... and a 3" inlet. Check out Mark P's pictures. -Dave Pramanik http://ctny.audiworld.com/mark/s4/downpipes/ __________________

08-20-2003, 12:19 PM	#8
~~Mike@VAST~~ Banned Account #: 21977 Join Date: Jul 2001 Posts: 19,481	stock main cats are 400 cpi too.

08-20-2003, 12:38 PM	#9
SmokinS4™ AudiWorld Super User Account #: 18942 Join Date: Apr 2001 Posts: 10,504	thanks - updated __________________ ------------------------------------------- -------------------------------------------- how's that for a short signature Stg4 S4.

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