Gutted Cat vs. Testpipe vs. Hi Flow Cat

[Fiveliter302]

OK, Ive done the usual searches, and really came up with no definative opinions on these as a comparison.
I also do not poke my head into the 2.5 forums too often so I might have missed something, but the time is nearing to get all the parts gathered and get my PGT up and running finally so Id appreciate the help.

A few things for additional info to help. I have purchased and have Bosal Ceramic Coated Headers for the car. I also plan on purchasing a Bosal Catback system. In my county in Ohio we have emissions testing.

Now, what I would like to know, preferably from people that have the aforementioned, is...

I know ultimately that the testpipe is the best performancewise, but is there a huge performance difference between a testpipe and a gutted cat? I really cant see there being too much of a difference. I just dont want it to be noticed that Im not running a cat if I decide to go with one of these two methods.

ALSO

If someone has a High Flow Cat, did you notice a huge difference performancewise between the stock cat (if it was unfouled when taken out) and the High Flow. Also, if you have emissions testing, did the high flow pass emissions?

Our emissions testing is every two years, and if there is not a huge decrease in performance between the High Flow and an open pipe (whether testpipe or gutted cat) I would probably stick with that but Im not sure yet what Ill do... Of course I expect there to be somewhat a decrease going from an open pipe to any sort of cat, but just wondering how huge of a decrease in power it might be...

Any other opinions in helping me decide would be great also...

[GTblaze]

Yes, there will be some differences in the test pipe vs. hi-flow cat. The hi-flow will be alot better than the stock though. If you don't want anyone to notice then you probably shouldn't get the test pipe. Besides the fact that you can easily see that there is not cat anymore, most of them are fairly louder than a cat. Gutting a cat will probably still make your car fail emissions. If you want to stay legal and still get some performance then go with the hi-flow and you won't have to worry about anything. They will still pass emissions.

[jones93pgt]

i am assuming that the point of almost anybody getting a hi flow cat would be to get more over stock and still be legal. I haven't seen to many non-50 state legal cats.

[Mikal]

The only way I could explain this is like this. Its gross but it gets the point across. Think of your exhaust as your butt. If you have a tight hole, the poop just shoots out fast (TEST PIPE) If you have a loose hole then it just comes out slowly. Gutted cat :-) I hope this helps Laters Mikal

[jones93pgt]

Originally posted by Mikal
The only way I could explain this is like this. Its gross but it gets the point across. Think of your exhaust as your butt. If you have a tight hole, the poop just shoots out fast (TEST PIPE) If you have a loose hole then it just comes out slowly. Gutted cat :-) I hope this helps Laters Mikal
works for me!:tup:

[SLEEPER 626]

I have the same setup as you. Bosal Headers and Bosal Catback.

I started with a Random Technologies Hi-Flow Cat and then I tried a Test Pipe.

I really didn't notice any performance gains betwee the two.

Recently, I had to put the Hi-Flow Cat back on for Emissions Testing (Which I barely Passed!), and to be honest with you....

I like the Hi-Flow Cat better. Same performance, but the sound is much smoother/deeper.

What makes it sound better? I have no idea. All I know is I was never impressed with the sound of the Test Pipe....and never saw any significant gains.

The advantage of a Test Pipe is it will never get clogged with carbon (my car is running rich and there is a noticeable presence of black soot at the tail pipe). A Hi-Flow Cat may clog over a period of time.

I hope this helps.

Good Luck!

:tup:

[Fiveliter302]

Originally posted by SLEEPER 626
I have the same setup as you. Bosal Headers and Bosal Catback.

I started with a Random Technologies Hi-Flow Cat and then I tried a Test Pipe.

I really didn't notice any performance gains betwee the two.

Recently, I had to put the Hi-Flow Cat back on for Emissions Testing (Which I barely Passed!), and to be honest with you....

I like the Hi-Flow Cat better. Same performance, but the sound is much smoother/deeper.

What makes it sound better? I have no idea. All I know is I was never impressed with the sound of the Test Pipe....and never saw any significant gains.

The advantage of a Test Pipe is it will never get clogged with carbon (my car is running rich and there is a noticeable presence of black soot at the tail pipe). A Hi-Flow Cat may clog over a period of time.

I hope this helps.

Good Luck!

:tup:

Hmmm.... new twist to the whole idea of High Flow vs. Testpipe...

Nice :thup:

Where did you get the cat from?

[SLEEPER 626]

Originally posted by Fiveliter302


Hmmm.... new twist to the whole idea of High Flow vs. Testpipe...

Nice :thup:

Where did you get the cat from?


I bought it in May 2001 from Martel Brothers Perforance 1-800-882-7223. martelbrothers.com

Hi-Flow Cat $184.11 (S&H included)
Install Kit (Bolts and Gaskets) $15.74 (S&H included)

Total = $199.85

I have not been disappointed. I am very Impressed with the quality in construction and materials.


:tup:

[Mikal]

I think the soundof a test pipe is Hondaish. Again with the butt analogy. The test pipe being narrower so t changes the sound to a higher pitch like when you squeeze your cheeks together for a fart. A Hio flo cat is more loose so it lets air flow through better I guess. So you get a deeper sound :-) Laters Mikal

[jones93pgt]

Originally posted by Mikal
I think the soundof a test pipe is Hondaish. Again with the butt analogy. The test pipe being narrower so t changes the sound to a higher pitch like when you squeeze your cheeks together for a fart. A Hio flo cat is more loose so it lets air flow through better I guess. So you get a deeper sound :-) Laters Mikal

So in respects to that would it sound "deeper" and less "hondaish" if you just hollowed the cat?

(I don't have to worry about passing emissions)

[Fiveliter302]

Originally posted by jones93pgt


So in respects to that would it sound "deeper" and less "hondaish" if you just hollowed the cat?

(I don't have to worry about passing emissions)

I think it would sound deeper (acting as a resonator), but I think I had heard somewhere that the gutted cat still restricted the flow somehow (as Mikal would probably say "constipated" :razz: )...

[jones93pgt]

that is what i was thinking (restricting) but i think i will save the money and put in a test pipe. oh yea, and what about that mesh before it...does that have to be replaced with the mesh?? i would assume it has something to do with flexing etc.. but i am not sure...mine is leaking, that is why i ask

[Rocket]

a gutted cat is the most RASPY combination possible.

[Fiveliter302]

Originally posted by jones93pgt
that is what i was thinking (restricting) but i think i will save the money and put in a test pipe. oh yea, and what about that mesh before it...does that have to be replaced with the mesh?? i would assume it has something to do with flexing etc.. but i am not sure...mine is leaking, that is why i ask

I think youre talking about the flexpipe... If the flexpipe is leaking you should replace it...

[jones93pgt]

Originally posted by Fiveliter302


I think youre talking about the flexpipe... If the flexpipe is leaking you should replace it...
so with that, i would assume that you have to replace it with the flex pipe?

[Deamonicus]

The only way I could explain this is like this. Its gross but it gets the point across. Think of your exhaust as your butt. If you have a tight hole, the poop just shoots out fast (TEST PIPE) If you have a loose hole then it just comes out slowly. Gutted cat :-) I hope this helps Laters Mikal

So that's what's wrong with my A$$! :grin:

[sparky93]

I work at meineke discount muffler and am an ASE certified mech, unfortunatly. Anyway as said above a cat does' act as a resonator for a couple of reson's, 1 the exhaust gas's are expanding and losing their velocity and 2 cat's ceramic core's are mounted in their with fiberglass and steel wool to protect them from vibration. High performance cat's are really a misnomer unless the perforation hole's in the ceramic core are bigger, if their not then your high performance cat is really just performance based on the bigger inlet and outlet diameter's. Within the next month I will making some flanged cat's and testpipe's out out of T304 stainless in size's from 2" to 3", Email me if interested and I'll quote ya'll some price's which will be near half of what you would pay for a Random or equivelant because I get them for cost from our supplier. Don't get me wrong I like Random cat's but 200.00 is what we charge at Meineke to custom install one. Zach formally known as Kamikazi89.

[PGT-punker]

i was wondering how difficult the installation of a test pipe is, emissions tests arent a problem here :) even though its illegal so i would opt for installing it myself so i dont gotta try and find someone to do it without reporting me any help would be appreciated

[TakimanPGT]

Jack up car.
Place jackstands.
Unbolt four bolts for the cat.
Remove cat.
Replace with Test Pipe.
Bolt back four bolts.
Remove stands.
Lower jack.

Congrats, yo. Your done.

[Evil Probe]

Originally posted by TakimanPGT
Jack up car.
Place jackstands.
Unbolt four bolts for the cat.
Remove cat.
Replace with Test Pipe.
Bolt back four bolts.
Remove stands.
Lower jack.

Congrats, yo. Your done.

Now if it were only that easy to do with rusted bolts. Had to use an impact wrench to loosen those bastards off. I love my tp though! Also, it comes with all the nuts, bolts, washers, and gaskets that you need. :tup: to Jeff Jeske!

[Ltsrunem]

This is what I did. I wanted a testpipe at first but I didn't want the bumble bee sound so I bought a Dynomax tube muffler and put it in place of the cat. It's not a direct fit though. It still has the straight through design and it has sound deadening material.

I put it on with a small resonator and I love it. I had to have my exhaust custom(mandrel bent) because of this. All and All it cost me about $90(I know the guy at the muffler shop.)


WES

[summit93gt]

hey i live in ohio around the cleveland area and i am running a gutted cat with a straight pipe exhaust when i got e checked i popped my muffler back on and passed the e-check just fine gutted cat and all just when you go run 93 octane gas and you'll be fine.