# Cat-less vs Catted



## ShutItDown (Jun 14, 2007)

Some interesting information on test pipe vs cat. Would be useful when looking for a ATP cat-less DP vs catted DP's.
http://evoempire.org/Test-Pipe...rplus


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## Josein06GLI (Jun 29, 2008)

my boy has a apr downpipe and i have the atp catless. neither one of us have software and we both have dsg and i pull on him a little bit, its a straight pipe, also maybe its just me, i think the car warms up quicker in the mornings.


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## wazzap1101 (May 1, 2009)

the bottom line is the catted is more restrictive than non-catted. 
WIth a cat, you're sacrificing performance to pass inspection and be more environmentally friendly. It all depends if your willing to make the tradeoff, and personal preference.
BTW, nice info ShutItDown


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## ShutItDown (Jun 14, 2007)

*Re: (wazzap1101)*


_Quote, originally posted by *wazzap1101* »_the bottom line is the catted is more restrictive than non-catted. 
WIth a cat, you're sacrificing performance to pass inspection and be more environmentally friendly. It all depends if your willing to make the tradeoff, and personal preference.
BTW, nice info ShutItDown

No problem. Everyone know a cat is more restrictive but all these high flow 100 cell cats that claim to be the same performance as test pipe set up and this is some good information against it.


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## MK3Serge (Apr 29, 2006)

*Re: (ShutItDown)*

i run an ebay DP with a magnaflow 200cell cat..i did it mainly to pass emissions but i did notice the power and the sounds mated to the stock exhaust is much nicer than i expected


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## [email protected] USA (May 17, 2007)

*FV-QR*

I run a cat with my GT3582R


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## SmithersSP (May 24, 2006)

*FV-QR*


_Quote, originally posted by *MK3Serge* »_i run an ebay DP with a magnaflow 200cell cat..i did it mainly to pass emissions but i did notice the power and the sounds mated to the stock exhaust is much nicer than i expected


I have the same setup. It wasn't that I needed it to pass inspection, or that I'm a treehugger; more so that I got sick of the ass end of my GLI smelling of raw unspent fuel... While I doubt my car would pass a comprehensive emissions test the cat takes car of the fuel smell...


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## bostonaudi1 (May 14, 2006)

*Re: (wazzap1101)*


_Quote, originally posted by *wazzap1101* »_the bottom line is the catted is more restrictive than non-catted. 
WIth a cat, you're sacrificing performance to pass inspection and be more environmentally friendly. It all depends if your willing to make the tradeoff, and personal preference.
BTW, nice info ShutItDown


BS
Sure, but somehow Porsche, Corvette and many others can extract 400+ hp easily with cats in place. You're "sacrificing" almost NO performance with a high flow cat, and performing the completely selfish act of trashing the air for EVERYONE else when removing it. 
I ME MINE




_Modified by bostonaudi1 at 5:58 PM 11-13-2009_


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## Shazsta (Mar 9, 2006)

*Re: FV-QR (SmithersSP)*


_Quote, originally posted by *SmithersSP* »_
It wasn't that I needed it to pass inspection, or that I'm a treehugger; more so that I got sick of the ass end of my GLI smelling of raw unspent fuel... 

same here. that ish stunk


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## Josein06GLI (Jun 29, 2008)

i have an atp catless DP nd i love it cuz it was 300 bucks and mainly cheaper cuz it doesnt have a cat, a catted DP runs upwards of like 500-900 depending on what brand, catless for me, who cares what it smells like, get chipped and u wont even need a spacer for u catless dp guys


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## SmithersSP (May 24, 2006)

*FV-QR*

I couldn't help but notice you live in SD. If you don't mind me asking; how do you pass a smog check?
Thanks!


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## ShutItDown (Jun 14, 2007)

*Re: FV-QR (SmithersSP)*

How often do you have to check your car? I would assume he would just put the other one on before he has to check it.


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## Josein06GLI (Jun 29, 2008)

well in cali the car isnt due for smog until its 6 years old, my GLI is an 06 so its due for its first smog in 2012, at which point i WILL NOT own the car anymore and if i do theres places to get it done "under the rug" using a dummy car


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## [email protected] USA (May 17, 2007)

*Re: (Josein06GLI)*


_Quote, originally posted by *Josein06GLI* »_well in cali the car isnt due for smog until its 6 years old, my GLI is an 06 so its due for its first smog in 2012, at which point i WILL NOT own the car anymore and if i do theres places to get it done "under the rug" using a dummy car

Wow 6 years... and people complain about smog in california? Even here in Georgia they do it after 2 years.. NJ was 4 years on new car and some states are even 1 year. I think NC smogs cars before they are delivered to the dealers..


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## rippie74 (Sep 26, 2007)

*Re: (bostonaudi1)*


_Quote, originally posted by *bostonaudi1* »_
BS
Sure, but somehow Porsche, Corvette and many others can extract 400+ hp easily with cats in place. You're "sacrificing" almost NO performance with a high flow cat, and performing the completely selfish act of trashing the air for EVERYONE else when removing it. 
I ME MINE
_Modified by bostonaudi1 at 5:58 PM 11-13-2009_

You said: "Porsche, Corvette and many others can extract 400+ hp easily with cats in place". I say Yea, but do you realize what kinda power those cars would have if they had the cats removed? It would blow your mind, You'd be shocked @ how much more power they'd have. That is why I choose to run the ATP.


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## MFZERO (Mar 13, 2002)

*Re: Cat-less vs Catted (ShutItDown)*

it's an age old battle.
p.s. the first link doesn't work


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## Krieger (May 5, 2009)

*Re: (rippie74)*

that honeycomb in a cat will not rob u of much power.
even in turbo charged cars ur really only gonna gain a VERY minimal amount of ponies over a catted pipe... and the difference is even less on a N/A engine as they need back pressure to keep the exhaust flowing right and maintain the exhaust pulse and velocity as it travels down the system.

i run catless, but as soon as i get around to it, imma hack up my pipe and weld in a nice metallic cat, i will then dyno my car again and prove to u that just like all the other cars ive ever worked on, this one wont lose much, if any at all, horsepower or torque just because a thin catalytic material happens to be in the system...


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## rippie74 (Sep 26, 2007)

*Re: (Krieger)*

In high school (1991) my buddy had (& still has) a 1988 Monte Carlo SS. He put a _400whp - 383 Stroker in it w/Dart heads & a 750cfm carb. Art Carr Transmission with 4.10 grears in the rear_ 
The car had a custom dual exhaust installed consisting of two, 2.5" pipes leading into "2 chamber" (loud as hell) Flowmaster mufflers & that was it. It was a friggin beast. 
One day we got pulled over & the cop actually went down on his hands & knees & looked at his exhaust. Thus busting him for no cats. So he went back to the exhaust shop & had them weld in to high flow race cats & afterwards I drove the car. The diffeerence was night & day.
Before the cats were put on, the car hauled ass during the mid range & top end it was incredible. _After the cats were installed it lost ALL of that._ Now down low it was a torque monster, but the midrange & top end were non exsistant compared to before.










_Modified by rippie74 at 4:31 PM 11-17-2009_


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## SmithersSP (May 24, 2006)

*FV-QR*

I'm neutral in this debate so I'm just asking for curiosity sakes; what type of cats were they? Were they standard oem-ish cats or low cell count metallic spun cats?
Thanks!


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## Josein06GLI (Jun 29, 2008)

i run catless, but as soon as i get around to it, imma hack up my pipe and weld in a nice metallic cat, i will then dyno my car again and prove to u that just like all the other cars ive ever worked on, this one wont lose much, if any at all, horsepower or torque just because a thin catalytic material happens to be in the system...
i know u said u were running catless dp, why would u want the risk possibility of losing any if any horsepower or torque ????


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## Krieger (May 5, 2009)

*Re: (Josein06GLI)*

because if this car is like any other turbo charged car ive ever played with or worked on, the losses will be negligible.
and if u can feel the loss of like 4 or 5 HP, ur a freak. lmao
this car runs SUPER rich, so if i catch a wiff of my car's a$$ fumes, it brings a tear to my eye cuz it actually stings when u breath and ****. lol


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## StuMacLean (Aug 9, 2003)

*Re: (Krieger)*

You guys with the ebay DP's and cats. What did you do, buy the ebay DP, then have an exhaust guy weld in the cat? Is the cat in the DP or somewhere downstream in your exhaust? 

Could I use one of, or both of the stock cats with the ebay DP and expect good results, or do I need to get a better flowing cat?
Thanks


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## Krieger (May 5, 2009)

*Re: (StuMacLean)*

stock cats are small, thick, and super restrictive.
i have an ebay pipe cuz it works, but im gonna get a 200 cell metallic cat. might be from magnaflow, but i like random technology too.


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## SmithersSP (May 24, 2006)

*FV-QR*

I bought my catless DP and magnaflow 200 cell cat off ebay. I have a shop weld in the cat. To be honest I didn't notice any difference in the power of the car. I didn't do a pre/post dyno though so who knows for sure...


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## Krieger (May 5, 2009)

*Re: FV-QR (SmithersSP)*

yeah, you wont. your turbo is still gonna be spooling like a beast simply because you got rid of that first cat that was like a brick wall, plus gave it PLENTY of room to flow afterwards. it's not like the honeycomb of a cat is such a huge restriction... ****, most flow more than alot of mufflers.... so if u dont notice a drop in power from a muffler, why would u from a cat?
100 cell metallic








200 cell








neither will block much flow at all... they are far back enough in the exhaust that your turbo will see almost no build up in back pressure... Now, if u went with a much bigger turbo that could move alot more exhaust, faster, u might lose more, but with a K03 or K04, ur not gonna choke up the system.


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## Josein06GLI (Jun 29, 2008)

well which brings me to the next topic of catted and non catted dp's. first and formost especially with the economy as fuc*ed as it , non catted dp's are wayyyyy cheaper and a quick way to get to stage 2 power when chipped. when i did mine i didnt have 1000 for an APR 200 cell catted dp so i went with an atp catless, i love it, no issues and its been on the car for a while i got 71k miles on my 06 and put it on around 20k or so, no rust either, plus it was used and i go for like 300 shipped. 700 bucks saved, wheres the problem? lol


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## Krieger (May 5, 2009)

*Re: (Josein06GLI)*

u paid 300 for a used catless ATP pipe??? dude, u overpaid... i got mine for 160 shipped to my door, new, and its an exact replica of the ATP. welds are fantastic and fit perfectly. hell, new ATPs are 360.
but anyways, u can buy a cat for a decent price http://www.clubrsx.com/cr/VIB-...oogle
this thing flows REALLY well and i used it on my last car plus helped my bro install alot of these. good construction and last for a long time with no rattles or ****.


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## applen (Sep 27, 2005)

*Re: (Josein06GLI)*


_Quote, originally posted by *Josein06GLI* »_ 700 bucks saved, wheres the problem? lol

well there is that whole global warming thing we got goin on here... thanks for your generous contribution http://****************.com/smile/emthdown.gif


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## rippie74 (Sep 26, 2007)

*Re: (applen)*


_Quote, originally posted by *applen* »_
well there is that whole global warming thing we got goin on here... thanks for your generous contribution http://****************.com/smile/emthdown.gif 

Global Warming? uncatted 2.0T VW's hardly contribute to that isht. Things like HUGE Factories & Chemical Plants etc... etc... take their tool on the enviornment.


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## Krieger (May 5, 2009)

*Re: (rippie74)*


_Quote, originally posted by *rippie74* »_
Global Warming? uncatted 2.0T VW's hardly contribute to that isht. Things like HUGE Factories & Chemical Plants etc... etc... take their tool on the enviornment.

this. the 2.0T is a very clean engine, except for running rich.
BUT, its still better if we all had cats... but hey, what are u gonna do about it.

__
Image uploading. Refresh page to view


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## SmithersSP (May 24, 2006)

*FV-QR*

Actually Rippie I believe that automobiles are the source of the majority of air pollution today. Couple this with the fact that my FSI run 12:1 at WOT and that leaves the potential for a large quantity of co2 and NOx emissions.








P.S. As an engineer I believe that we'll all screwed unless we change our primary energy source period. In the long term one catless dub won't level a rainforrest. That being said a catless car is worse for the environment than a catted one.


_Modified by SmithersSP at 7:58 AM 11-19-2009_


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## Josein06GLI (Jun 29, 2008)

thanks rippie for the defense and i just looked at paypal and i paid 180 for the dp and it spend like 60 bucks on tools to install myself so almost 3 bills. ok not wanting to fight or argue via internet this is a forum and everyone does have an opinion i stated mine. love it or hate i dont care


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## bostonaudi1 (May 14, 2006)

*Re: (Krieger)*


_Quote, originally posted by *Krieger* »_stock cats are small, thick, and super restrictive.
i have an ebay pipe cuz it works, but im gonna get a 200 cell metallic cat. might be from magnaflow, but i like random technology too.

The pre-cat on the Mk5 is definitely a restriction, I run an AWE downpipe w/metal cat and my engine revs ridiculously fast and makes a ton of power with the stock K03. Taking that first one out is key. I feel no need to run totally cat free. 
The cheapo $100 ceramic cats that usually come w/aftermarket systems are sometimes more restrictive than factory cats, which aren't always that bad.
A cat is a modern miracle invention, for a slight restriction, it cleans the heck out of the exhaust. Anyone remember seeing pictures of LA basin from the 60's during a smog inversion?











_Modified by bostonaudi1 at 8:30 PM 11-19-2009_


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## RABIDRABBIT1983 (May 13, 2003)

*Re: (bostonaudi1)*

i have a catless 42DD 3" setup on my mk5 gti. I went this route cause im a cheap ass and it was much cheaper to go catless. 
The stock cats main downfall is because its RIGHT after the turbo. a QUALITY highflow aftermarket cat vs catless gains are marginal at best when talking about running a ko3 or ko4 turbo. 
please spare us the 1990 cat analogies guys.............that is beyond outdated moot point. 
I have a customer with a BMW Z-3 that did some insane custom turbo, meth injection, built motor, HUGE custom wheels out back(he's an engineer and did the majority of the stuff himself). I asked him his thoughts on why with all that power over 500 wheel. he was still using a stock cat welded into his custom exhaust..........he said you know I did a test pipe setup on the dyno and saw MAYBE 10 crank hp......he felt that was not worth the trouble in the scheme of things seeing as how he could not hook at all anyways!
FWIW im going to add a cat to my setup because my garage smells HORRIBLE for at least 1 hour when i get home and it drives me crazy. I do back into the garage which adds to the issue. 


_Modified by RABIDRABBIT1983 at 4:49 AM 11-20-2009_


_Modified by RABIDRABBIT1983 at 5:59 AM 11-20-2009_


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## bostonaudi1 (May 14, 2006)

*Re: (RABIDRABBIT1983)*


_Quote, originally posted by *RABIDRABBIT1983* »_
I have a customer with a BMW Z-3 that did some insane custom turbo, meth injection, built motor, HUGE custom wheels out back(he's an engineer and did the majority of the stuff himself). I asked him his thoughts on why with all that power over 500 wheel. he was still using a stock cat welded into his custom exhaust..........he said you know I did a test pipe setup on the dyno and saw MAYBE 10 crank hp......he felt that was not worth the trouble in the scheme of things seeing as how he could not hook at all anyways!
FWIW im going to add a cat to my setup because my garage smells HORRIBLE for at least 1 hour when i get home and it drives me crazy. I do back into the garage which adds to the issue. 


That factory BMW cat is most likely metal core. It is well known fact that the factory exhaust on the E36 M3's make all the power you'll ever need, most aftermarkets for that car do nothing other than add noise...


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## B4LLS4GN4 (Oct 7, 2008)

*Re: Cat-less vs Catted (ShutItDown)*

cats? i prefer dogs. definitely catless. who cares about emissions, pollution still exists wether its coming from your car or not.


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## Krieger (May 5, 2009)

*Re: Cat-less vs Catted (B4LLS4GN4)*


_Quote, originally posted by *B4LLS4GN4* »_cats? i prefer dogs. definitely catless. who cares about emissions, pollution still exists wether its coming from your car or not.

baby steps. if everyone put it back in there and we actually obeyed the laws that are written and passed for a reason, it would be alot cleaner on our little dirt ball in space.
im actually having a 200 cell metallic cat put in next week... cant wait! gonna dyno after to see if i lose anything.


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## rippie74 (Sep 26, 2007)

*Re: Cat-less vs Catted (Krieger)*


_Quote, originally posted by *Krieger* »_
baby steps. if everyone put it back in there and we actually obeyed the laws that are written and passed for a reason, it would be alot cleaner on our little dirt ball in space.
im actually having a 200 cell metallic cat put in next week... cant wait! gonna dyno after to see if i lose anything.

It'll never be that way thats why you'll always have some who do & some who don't.


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## Krieger (May 5, 2009)

*Re: Cat-less vs Catted (rippie74)*

oh, i know, im just saying, its better if your choose to do it, and the rest of the people on here too. i mean, think about it, if all us euro guys had cats, and the ricers had cats again, thats pretty much everyone out there except cycles and track spec cars.
but, idk, and i dont really see a point at this point. there is enough C02 in the air that its causing climate change faster than anyone thought possible, so we just need to be ready when the **** hits the fan.


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## RABIDRABBIT1983 (May 13, 2003)

*Re: Cat-less vs Catted (Krieger)*

when i get an extra buck im going to put a cat on my 42DD setup. Its a hydrocarbon party in my garage for at least 2 hrs everynight when I get home. its obnoxious!


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## INYNN (Apr 14, 2008)

Catless DP all the way! Runs great and smells great too.


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## itzkv (Oct 16, 2009)

*FV-QR*

I have a catless DP, i regret it now. The smell has gotten on my nerves once it starts to seep its way into the cabin..


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## Krieger (May 5, 2009)

*Re: FV-QR (itzkv)*

then just buy a cat off the net and have a local place weld it in. i was quoted 165 for a magnaflow 200 cell installed. cant wait.


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## firstorbit84 (Feb 25, 2006)

Krieger said:


> im actually having a 200 cell metallic cat put in next week... cant wait! gonna dyno after to see if i lose anything.


 Bumping old a$$ thread. 
Has this guy or anyone actually dynoed a stg 2 car with catless downpipe and then catted? 

I just put a 200 cell magnaflow from 42dd on my 3" dp and could definitely notice some mid-top end losses.


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## bryangb (Jun 16, 2010)

Cats are for hippies


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## xtravbx (May 21, 2005)

firstorbit84 said:


> Bumping old a$$ thread.
> Has this guy or anyone actually dynoed a stg 2 car with catless downpipe and then catted?
> 
> I just put a 200 cell magnaflow from 42dd on my 3" dp and could definitely notice some mid-top end losses.


 
The butt-dyno is really capable of feeling a loss of maybe 3-6hp? I have my doubts. 

Maybe it SOUNDS different up top now, and youre linking the lack of audible "power" to real power? 

Not trying to be a jerk - but I don't think you could actually notice that small change in power.


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