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View Full Version : cons of using straight pipe, no cat



badness
01-14-2008, 09:01 AM
i think that my cat might be failing, causing check engine light came on, plugged in VAG tool and could either be bad O2 sensor or the cat. if it is the cat i can get it replaced for free cause i only have 42000mi on car and there is a problem with factory cats i guess and they will replace if under 80000. but i have always wanted to put a test pipe on instead of cat but i have always worried that the check engine light would always be on. is this true? the pipe i want to put on has dedicated places for the sensors but i have thought that i heard the check engine light would still be on. does anyone know about this stuff. they don't check emisions here so i don't have to worry about this.

smithm5
01-14-2008, 09:06 AM
they have files to remove the CEL for that....atleast APR did for my B6. If you are chipped, they will usually have a option for testpipes.

it also sounds better with exhaust :)

grip_racer
01-14-2008, 09:37 AM
cons?

-smelly exhaust -- bad if youre dating.
-emissons, but you don't have that. it's still bad for the envronment though.

search "anti-fouler" or "diode" for the CEL fix.


honestly though, just get a La Bree high flow cat. It bolts in, gives better performance, wont smell, and won't throw a CEL.

A4Rollin
01-14-2008, 09:54 AM
+1, get the labree hi flow cat. It is a good product and you can notice a slight difference in throttle response. If you ever get that cel you should use the defouler method, you can make one yourself or there is someone on the classifieds that has several of them.

badness
01-14-2008, 11:16 AM
thanks everyone. but the test pipe is only like $150 from atp turbo and the high flow cats you guys are talking about are like $900 right. i didn't want to spend that much. i have a chip from wetterauer, most of you probably havn't even heard of them, got it back about six years ago so do you think there is an option on it? how would i find out that. and as far as the files that can be erased, would my shop know how to do that with the VAG? thanks.

A4Rollin
01-14-2008, 11:22 AM
$900 ????? thats ridiculos, i got mine for 320 which is still expensive to me

////D
01-14-2008, 11:23 AM
i got a eurocode 3" test pipe, and i have no code with antifouler mod on the aeb

Solaris
01-14-2008, 12:08 PM
thanks everyone. but the test pipe is only like $150 from atp turbo and the high flow cats you guys are talking about are like $900 right. i didn't want to spend that much. i have a chip from wetterauer, most of you probably havn't even heard of them, got it back about six years ago so do you think there is an option on it? how would i find out that. and as far as the files that can be erased, would my shop know how to do that with the VAG? thanks.

Tantrumwerks sells the Labree HFC for $260. I had the old style 400 cell HFC before the welds melted just like the OEM cat, then I went to the test pipe while I had to ship the cat back to get fixed. I'm only going to use the HFC for inspection. I was getting the CEL with even the HFC (and others have,too), so it's likely you'll need some kind of trick for the O2 sensor in either case. The non-fouler mod has been working flawlessly for me on the test pipe.

badness
01-14-2008, 12:34 PM
solaris; could you give me your impersions (butt dyno) of factory cat, hfc, and test pipe. can you tell a difference between the hfc and test pipe? also, what exactly is this anti-fouler or non-fouler mod anyway?

A4Rollin
01-14-2008, 12:43 PM
hi flow cat and test pipe are about the same except the fact that a hiflow cat is better for emissions!
He is the link on the defouler method, someone is actually selling them in the classifieds. It basically pushes the 02 sensor further back so it doesnt throw cels all the time
http://www.audizine.com/forum/showthread.php?t=170172

ct1.8t4me
01-14-2008, 12:55 PM
If the cat is being replaced for free - including labor - this is what I would do:

#1 Have them replace the cat.
#2 Buy an ATP test pipe - I think they are about $160
#3 Swap them and put the cat on the shelf or sell it.

Since they will be in there mucking around, they will get the honor of dicking around with rusted over bolts and all the other BS that makes a testpipe install suck. You will have nice fresh hardware to work with and the install should be alot easier.

Just a thought.

Also - test pipes sound amazing.

Solaris
01-14-2008, 12:57 PM
solaris; could you give me your impersions (butt dyno) of factory cat, hfc, and test pipe. can you tell a difference between the hfc and test pipe? also, what exactly is this anti-fouler or non-fouler mod anyway?

Going from the OEM cat to the HFC, the turbo seemed to spool up a little quicker and it made for better low end power. I didn't really notice a difference going from the HFC to the test pipe.

Solaris
01-14-2008, 12:58 PM
If the cat is being replaced for free - including labor - this is what I would do:

#1 Have them replace the cat.
#2 Buy an ATP test pipe - I think they are about $160
#3 Swap them and put the cat on the shelf or sell it.

Since they will be in there mucking around, they will get the honor of dicking around with rusted over bolts and all the other BS that makes a testpipe install suck. You will have nice fresh hardware to work with and the install should be alot easier.

Just a thought.

Also - test pipes sound amazing.

I like this idea, however, the Federal emissions warranty is 8 years/80k. Unless he bought the car after January 14th, 2000, it has expired.

supermario
01-14-2008, 01:37 PM
labree's hfc cost me 250$ + shipping and bolted on nicely and no check engine light or smells :)

Solaris
01-14-2008, 01:42 PM
labree's hfc cost me 250$ + shipping and bolted on nicely and no check engine light or smells :)

I didn't get the CEL right away, it took a little while. Seemed like driving with the RPM under 3k a lot is what set it off.

supermario
01-14-2008, 01:46 PM
I didn't get the CEL right away, it took a little while. Seemed like driving with the RPM under 3k a lot is what set it off.

yea but who drives with the rpm under 3k alot :)

Solaris
01-14-2008, 02:03 PM
those looking to save gas. On the roads I was driving, I could do 35 in 4th and 45 in 5th for extended periods.

SykoraA4
01-14-2008, 03:51 PM
maybe a stupid question, but will the exhaust shop swap my stock cat out with a test pipe? i was under the impression that they might be pretty strict about it because of whatever regulations regarding cats. it definitely would make things much easier on my part if they could do it when i get my exhaust done.

sorry if i threadjacked...

ILoveT
01-14-2008, 03:59 PM
In Indiana it is illegal for a shop to do that. I had it done on a previous car but the shop charged me. The money I paid most likely went straight into the workers pocket. If you use a real laid back shop then they most likely won't mind doing it though.