Im thinking of ordering the ZZP header/dp combo, should i go with Cat or No Cat. Will i see a major difference from one to the other?\

Also should I do 2.5 downpipe bolt on or the 3" DP with 2.5" exit?

Im going to get the Monza 2.5 catback with the combo

i've heard , if you loose your cat you loose low end TQ , just a thought !! good luck with choice

I think you should look at the XTC DP...Almost $50 dollars cheaper for the same thing..

BTW, I wouldn't even bother getting a DP if it wasn't catless...

would the CA header + XTC DP be cheaper then $400?

I cant look at Cobalt-addictions site at work, no Flash

The CA header + XTC 2.5" de-cat downpipe is $380. ($200 for the header, $180 for the de-cat DP). Go with 2.5"......3" is overkill for our cars. Plus, I don't understand why people wanna use a 3" DP to hook up to a 2.5" cat-back......kinda pointless.

hmmm...

There have been dynos showing running with no cat only yeilds around 2hp.

It's not worth the raspy sound and emissions issues. I say with high flow cat.

breaking in the cat is a pain,go catless

breaking in the cat is a pain,go catless

Lol...a pain...Mike....come on on bro....lol

You just can't WOT your car for 250 miles. I guess that could be a pain. :lol:

There have been dynos showing running with no cat only yeilds around 2hp.

It's not worth the raspy sound and emissions issues. I say with high flow cat.

Hey, I like my bit 'o rasp! Only raspy at WOT, deep at all other times.

I'm under attack. I'm putting the suit on folks. lol

http://www1.istockphoto.com/file_thumbview_approve/842320/2/istockphoto_842320_flame_boy.jpg

:lol:...

Guess it depends if you are worried about emissions issues, I believe the zzp high flow cat still sets a low efficency code. Stouffer said he has his light coming on after he got his. Guess just save your old stuff if you need to go through emissions so you can slap it back on. Think eliminating the cat all together will reduce the backpressure too much and actually hurt performance more then it would gain.

Cat-less...... I hate cats. :cussing: They're sneaky lil buggers that lay in wait until you pass by with a bowl of cereal....then BAM!!! they tackle your feet and you're fruit loops go flying.



I can help you out with the catless code issue anyway. If you're gonna pimp my services, you better partake :lol:

Cat-less...... I hate cats. :cussing: They're sneaky lil buggers that lay in wait until you pass by with a bowl of cereal....then BAM!!! they tackle your feet and you're fruit loops go flying.

I can help you out with the catless issue anyway. If you're gonna pimp my services, you better partake :lol:

^^^^ ha lol ha that is funny as hell

Leave the cat on. Helps with emissions and all that jazz. Won't have to keep putting it back on and taking it off. Just get a high flow.

Keep the cat. I've done it to 4, 6 and 8 cylinder cars and trucks and will never do it again. Why? You lose that low end torque and if you are racing, you will notice it. Any that raspy sound will qualify your car as rice, especially if you have a 6 inch fart can. Keep your exhaust quiet and high flowing. I personally like the exhaust quiet so I can 1) listen to the radio and 2) listen for any abnormal sounds the car would make while driving. But hell, to each their own.

^^^^ ha lol ha that is funny as hell

Thank you. :D Best part, true story from last weekend when I visited my parents.

i got the 2.5 zzp downpipe gonna get installed next week

Im not worried about emissions, OH did away with e-check/inspections... Its more of a noise thing then anything, if having the cat will keep it a little quieter without hurting performance id like to use the cat anyways.

Im not worried about emissions, OH did away with e-check/inspections... Its more of a noise thing then anything, if having the cat will keep it a little quieter without hurting performance id like to use the cat anyways.

Sweet, also go with the 2.5

Still, keep the cat on. Its helpin' your low end...and its emission's friendly.

I have 2.5 as well with the Magnaflow cat. Who says you can't WOT for 250 miles? :)

I just bought my catless dp for $100 shipped. Keep your eye open on the forum.

Catless and full 3" if you plan on making close to 300hp.....

A cat flows 99% of a straight pipe. Do you have emmissions where you live? If so the answer is a no brainer.

my engine keeps coming on and off...i got it deleted and it came back on again...omg im going crazy

your engine?? or your Check Engine Light?

Might be running too lean.

I've got the XTC 2.5 WITH CAT... and the cat blew its insides out... and now I have no low end power without much improvement in Top End. I can't roll race from 35 anymore... 40+ only.

I went catless 3" down pipe. tolerable with stock cat back. now with full 3" it is way to loud but I have the right sound. oh and there is rattles and vibrations like crazy. cat will be in two days. wish I could do a before and after but no time on dyno is available.

I just want a sound clip!

I just want a sound clip!

OK I got it. Not promising anything but I will try to get a few for you.

Here' is a quick sound clip Vid of my Exhaust...

http://s138.photobucket.com/albums/q268/USMCFieldMP/?action=view&current=20070828008.flv

GMPP Performance, XTC 2.5" with EMPTY cat, and GMPP Header.

Here's a Fly-by:

http://s138.photobucket.com/albums/q268/USMCFieldMP/?action=view&current=Fly-Bys002.flv

And another:

http://s138.photobucket.com/albums/q268/USMCFieldMP/?action=view&current=Fly-Bys003.flv

I just got my 3" in and out Cat. my exhaust is

- ZZP shorty header ceramic
- ZZP Catless DP
- Catylitic 3" in and out
- custom cat back with resonator and flo-pro muffler
this a full 3" system

I have a clip of it without cat. will post both without and with cat. let me tell you in car experience is the biggest part. cruising I have eliminated 95% of resonance. the experience can not come through on video tape cause you wont feel it on your chest....LOL. If your going 3" and it is a daily driver I totally recommend this system with cat. it is borderline tolerable. and I am ok with a loud exhaust system.

now I am ready for motor mods. next is cam's, cam gears, valve springs, port and polish everthing (head, intake and SC).
Then 10:1 pistons.

other than LSD and coil overs the car will be done IMO. should be close to 400HP at crank when done I hope.

immidiate need is an HE for intercooler.

I just installed my catless DP a few hours ago from zzp.
and so far im very happy.
I love the throttle response, the engine wants to rev alot more freely, especially at low RPM.
theres buttdyno increase, and i love the new tone.

all in all im very happy with it

so your not supposed to go WOT with a new high flow cat for 250 miles?

Dude I wish I had that road where I live, I'd be up and down it all day working on 1/4 times.

so your not supposed to go WOT with a new high flow cat for 250 miles?

correct

correct
I thought it was longer! I clogged mine,then went with it gutted which was better anyways.

Your going to have a CEL regardless, just so you know. I went with the high flow cat just to tone down the sound, and I'm glad I did cause I'm still trying to tone down the sound.

Your going to have a CEL regardless, just so you know. I went with the high flow cat just to tone down the sound, and I'm glad I did cause I'm still trying to tone down the sound.i got a CEL when doing this,turned it off and it never came back

yeah i can clear CELs with my dashhawk, and if it keeps coming back ill just have a buddy take care of it with HPT

ok thanks guys, CEL's won't be a problem, i can get that taken care of

Your going to have a CEL regardless, just so you know. I went with the high flow cat just to tone down the sound, and I'm glad I did cause I'm still trying to tone down the sound.

How about a kit that allowed you to tone it down and then with an allen key you can remove the kit and have more flow for track days or a night of fun? I am working on it.

i got a CEL when doing this,turned it off and it never came back
lol

funny I just got a cell today.

catless

catless

no catted

and why if you don't have emmisions its worthless. and if you went we a cti header like me you get 2 dp's one catless the other catted

and why if you don't have emmisions its worthless. and if you went we a cti header like me you get 2 dp's one catless the other catted

That would be dumb IMO.

nope depends on what you want

I just did a custom 3" catless setup on my car from manifold back using a Vibrant muffler. Yes its very loud, but im actually getting ready to take my exhaust back down and put in a vibrant super quiet resignator. As for issues u'll get cell codes going catless, but as for power, I notice alot of differance from 1st to 3rd but 4th and 5th pull about the same. If you have HPTuners and r not afraid of gettting a ticket for noise violations, or a ticket for not having a cat. Then go Catless otherwise hi flows. That simple!

People saying don't get a cat just because you don't have emissions testing need to wake up. Without a cat your putting out over 100 times as much polution, with a large chunk of what your putting out being extremely toxic. If he is only going with a 2.5" catback, he could easily get a hiflow cat that flows more then 500cfm (~ what a 2.5" flows).

Go w/ the cat, it won't hurt you at all...

[QUOTE=InfinityzeN;1445077]People saying don't get a cat just because you don't have emissions testing need to wake up. Without a cat your putting out over 100 times as much polution, with a large chunk of what your putting out being extremely toxic. If he is only going with a 2.5" catback, he could easily get a hiflow cat that flows more then 500cfm (~ what a 2.5" flows).[/QUOTE


for his application sure but if your going for a little more performance oriented then catless

Ok so what happens if I just happened to have....I dont know....WOT before 250 miles, about 100 times?

More than likely you posioned the cat.

nope depends on what you want

I would want a balanced 4cylinder not one with two cylinders restricted and the other two free flowing. that is why it makes no sense to run two cylinders on a cat and the other two not on a cat. as well 2 cylinders meet emmissions and the other two dont. if you cant see that well happy tuning. you have a cool setup.:twothumbs

I would want a balanced 4cylinder not one with two cylinders restricted and the other two free flowing. that is why it makes no sense to run two cylinders on a cat and the other two not on a cat. as well 2 cylinders meet emmissions and the other two dont. if you cant see that well happy tuning. you have a cool setup.:twothumbs

he actually has 2 diff dp that he interchanges as he needs, but im sure it stays catless 90% of the year

I would want a balanced 4cylinder not one with two cylinders restricted and the other two free flowing. that is why it makes no sense to run two cylinders on a cat and the other two not on a cat. as well 2 cylinders meet emmissions and the other two dont. if you cant see that well happy tuning. you have a cool setup.:twothumbs


WTF did you just say?:cussing:

Im thinking of ordering the ZZP header/dp combo, should i go with Cat or No Cat. Will i see a major difference from one to the other?\

Also should I do 2.5 downpipe bolt on or the 3" DP with 2.5" exit?

Im going to get the Monza 2.5 catback with the combo


http://cobaltss.net/images/sigs/sc_blue.jpg (http://cobaltss.net)

UHM I HEARD U LOOSE POWER AND TORQUE IF U GET WITHOUT THE CAT:bye:
BUT DO WHAT U WANT;)

lose power and torque with catless?!?!?!

where in the world did you hear that bs?

www.catlessmakesyoulosepower.com

ive been on the site and it is total BS

well that would mean adding a cat adds power right....


hot damn. im gonna add 3!

rice or not rice..

i wouldn't ever go without a cat on a car that is supposed to have one.

lose power and torque with catless?!?!?!

where in the world did you hear that bs?

the "tests" that were done involved taking the cat off of a car that otherwise had on. so, yeah, the car would freak out and lose power.

all the tests showed an increase.....

guys....seriously....think about what your saying

we spend all this time and money removing restrictions from exhausts.....

and somehow this giant fatass restriction right in the exhaust flow, is gonna ADD power.......

HELLOOOOOOOO

the only way a cat would ever result in a loss of power is if it induced a CEL on a car that has a failsafe mode that kicks in when the CEL is on. Our cars DO NOT have a fail safe mode that cuts fuel and in turn, power, when the CEL is on.

all the tests showed an increase.....

guys....seriously....think about what your saying

we spend all this time and money removing restrictions from exhausts.....

and somehow this giant fatass restriction right in the exhaust flow, is gonna ADD power.......

HELLOOOOOOOO

duh!

I should just put a cat on my intake so i can get an extra 5 whp

you mean you guys arent running a cat for each cyl? cmon.. I am in the 11's with this...
I have never heard of anyone removing a cat and losing performance.