# Catted or uncatted test pipe



## jaja123 (Jan 17, 2011)

Ok so a catted testpipe does not really make it a testpipe but as you all know usp has the option of a high flow cat. Now I have been debating to myself the last damn two weeks about this lol. I kind of asked this in another thread but want more feedback. Should I go get the catted one or the catless. Problem is im not a big fan of the smell a catless car produces and if im caught there is a very hefty fine. Chicago is a bit more strict on this I think and combined with my loud exhaust may attract too much attention. I just dont wanna spend the additional 150$. But right now both versions are 50$ off which makes the non catted 225$ and the catted 375$. Sale ends this Sunday so time is ticking. I heard it only smells of the windows are down or if im WOT. But if a cop is behind me will he notice? You guys would probably judge im pretty worried about this and would just tell me to spend more for the catted one. If I did get a cat would I loose power over the non catted or would it be pretty minimal.


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## MKVrabbit07 (Apr 7, 2011)

i've been debating on getting the catted version myself. in for some insight. opcorn:


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## jaja123 (Jan 17, 2011)

I contemplated adding a cat but thats too much trouble. And really you would not save much as a decent high flow cat is at least 100 bucks and then the trouble of fabrication. Also selling the pipe would be hard too if that was done.


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## TrillyPop (Jan 27, 2010)

The difference in performance and difference in sound will be limited/none between the two on your n/a car with 2.5" exhaust. Although it will smell a bit at lights and cold starts, the its not that easy for a cop to notice (and how often is a cop directly behind you and can tell that a smell is coming from your car and not the beater in the next lane anyways?). But if you're that worried about emissions and getting pulled over in your area, I would just fork over the extra and get the high-flow cat...for ease of mind if nothing else.


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## BlackRabbit2point5 (Sep 6, 2007)

Pretty sure if you're gonna do a high flow cat it would just be cheaper to pick up a universal and have it welded in place of the stock one. No sense in having a temporary highflow since you probably won't throw a p0420 unless your piping is big. If you want a quality test pipe though go for it, totally makes sense to get setup with something that's easy to swap with good fitment
Sent from my HTC Evo 4G Shift using Tapatalk


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## nothing-leaves-stock (Mar 1, 2005)

imo. i'd go WITH the high flow cat.
why?
-bit more back pressure which IS needed
-legal
-with "break up" the air flow in exhaust and not be as raspy
-better chance of no cel, or with software a better chance.


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## DerekH (Sep 4, 2010)

I agree, get a cat. I have a header with a high flow cat and i still get the smell when I'm at the lights in the summer. I don't really mind it though. You'll want the extra back pressure for sure, i learned that one the hard way.


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## jaja123 (Jan 17, 2011)

Alright thanks for the input. I was thinking about just swapping the cats but idk. That would probably run me 200-250$ vs the catted testpipe of 375$. And I do wanna switch to 2.5 inch for my whole exhaust down the line. Does anyone know the collector size for the headers? But its nice being able to swap it out and not hack up the stock one just in case I need it. I even considered welding one into the test pipe I kinda ruled that out as I would not save very much over the catted testpipe considering a good high flow is around 100$ bucks and then the trouble of welding it in. Also I can weld but dont have any sort of welder. So I think its better off paying the 150 extra and having it all set to go.


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## DerekH (Sep 4, 2010)

Collector on the header is 2.5


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## jaja123 (Jan 17, 2011)

awesome... catted testpipe it is. Surprised stock collector is 2.5 inch. Total is 396$ with shipping. A bit steep but whatever.


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## DerekH (Sep 4, 2010)

jaja123 said:


> awesome... catted testpipe it is. Surprised stock collector is 2.5 inch. Total is 396$ with shipping. A bit steep but whatever.


I don't think it is 2.5 on the stock exhaust manifold. it is on the aftermarket header though.


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## jaja123 (Jan 17, 2011)

well thats ok im never gonna buy 1000$ headers


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## jaja123 (Jan 17, 2011)

I heard our cars have two cats is that true? Are they both located in the factory pipe that the usp will replace? Anyone know what kind of core the usp cat has?


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## halbwissen (Jul 20, 2001)

I have a non-catted USP testpipe. 
Smell is minimal even when you're stopped for an extended period of time and have your windows down. 
The additional drone/rasp/brown tone is unbearable from 2,500-3,000rpm. 

To combat this, I added a Vibrant Ultra Quiet Resonator in the factory cat position, a Magnaflow 'bottle style' resonator in the midpipe area and there's a single muffler in it's usual position near the end of the exhaust system. 
Total exhaust diameter from exhaust manifold back is 2.5" - all stainless. 

With those modifications, the 'volume' of sound is equal to the stock pipe with cat, plus the bottle resonator and muffler. 
However, the 'quality' of sound is better. Sounds meaner, especially in the 7,000rpm range with my C2 SRI. 

The C2 tune accounted for no cat/high flow cat and with an oxygen sensor spacer, I've been CEL free for thousands of miles. 

I still have plenty of torque in the lower rpm range when daily driving and horsepower for miles past 4,000rpm (compared to stock manifold).

Overall, very satisfied with the outcome of this setup. :thumbup:


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## jaja123 (Jan 17, 2011)

did you put the vibrant after the test pipe?


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## halbwissen (Jul 20, 2001)

jaja123 said:


> did you put the vibrant after the test pipe?


I cut the testpipe right after the pre-cat oxygen sensor bung and put the Vibrant there.
The built-in oxygen sensor spacer (post-cat sensor) was removed and discarded. 
I will take a picture next time I have the car in the air. I have some GTI brakes I want to install, so I'll snap a shot then.


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## b1aCkDeA7h (May 27, 2008)

Pretty happy with my setup. Eurojet Header, Eurojet High Flow Cat, Techtonics Dual Borla Exhaust.

Compared to before the Eurojet stuff was installed, the noise is only a little louder under idle and normal driving, then wakes up after 3k. I'm sure my tune and the C2 SRI helps with that but yeah, I'd go with the cat for basically the same reasons Josh said a few posts up.


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## TylerO28 (Jul 7, 2008)

Hmm I think my exhaust is pretty quiet...but maybe the turbo muffles the sound a bit.
I'm currently
C2 log manifold-turbo-usp test pipe (no cat)-Eurojet exhaust.

Its not raspy, not very loud considering. But i'm my case I needed LESS back pressure. Really helped the turbo spool quicker! I'm quite impressed with usp's pipe. However the fitment to my turbo down pipe was a little tricky.it was a tight squeeze. And the flex section wasn't nearly as flexible as the OEM one. But the quality is way better!
I'm thinking about cutting off the usp pipe's section that allows OEM exhaust to fit and welding the section there.because it does taper right there. Overall I've thought about going 3"but can't justify the cost


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## jaja123 (Jan 17, 2011)

Tyler I think you can delete your" it may not be fast" signature:wave:


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## TylerO28 (Jul 7, 2008)

Lol... Its not fast.... It is"quick" ha ha
I think that suits the style i'm going for...

But your input has been noted. Maybe I'll switch it up


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