Okay so the time has come for my downpipe ugrade.

Im going ZZP but unsure if i want a kitty cat or no kitty cat.

So far with all the searches i heard on youtube the catted downpipe with muffler delete sounds the best.

BUT.....whats the hp difference from catted to catless?

Is the extra horses worth the loud obnoxious sound?

I currently have done the muffler delete....and it seems with the catted zzp downpipe it makes the awesome sound a bit louder and better.

But again im doing this for more horses not just for noise.....but if the catless option is only an additional 2 or 3 hp then screw it im going with the tree huggers.

Oh and im sure its the video or cam recorder but catless and muffler delete seem too loud.

I understand smell is an issue with catless.....wifey will have to put up with it....LOL

Please help!

 

I don't have a muffler delete, so I can't exactly answer your questions- but with a muffler it isn't obnoxious. It did however, make the car noticeably louder. Whether or not it would be obnoxious with a muffler delete depends on the person- some like it, I personally wouldn't like it. At first I had regretting getting the catless pipe because of the smell, it really bothered me at first but now I don't mind it and hardly notice it at all.

You're right about the performance difference though, it isn't going to be much 2~ HP probably. Also consider when thinking about performance, that the catless pipe is going to be lighter than the catted one as well.

 

Catless all the way. I dont have muffler delete and at first, as stated above, I didnt like the smell. but the performance is great. Just keep your normal downpipe if you need to do emissions and swap it in

 

***** out. Catless dp stock res no muffler.

 

catless DP with stock exhaust sounds good. Has a little sound while running and at low revs. But it opens up and screams when you start hitting boost =D

 

When I upgrade, I'll be sticking with a cat, but upgrading. Mine's a dd - I'm not planning to go full radical with the car, so it'll be most of the 'typical' mods.

 

***** out squared. Do a 3" from turbo back, no cat, resonator, 3" in/out muffler or no muffler.

 

I too want to go ***** out. If i get it hp tuned i dont need an angled bung?

Can anyone also confirm catless and muffler delete sound good. I have a feeling im gonna need to reinstall the muffler.

 

its going to be too loud for daily duty IMHO. I have the 3" from turbo all the way back from Hahn, its low smooth and when you punch the go pedal it gets loud and torque steers like a bull for 8 seconds. LOL

 

I have a high flow catted dp on the stock exhaust, with the muffler, and I think it's just fine. I went catted because for that 2-3 hp that you gain by going catless, I didn't feel was worth the noise, or the risk of getting a $900 ticket for removing your emissions equipment. Not destroying the environment was just a bonus . I'm also GMS1 so that was the other reason as I didn't want it to throw a code.

 

What's with you guys complaining about the smell? It smells like a MAN'S car.

But to the OP - the power you gain from going catless is directly related to the amount of power you're trying to make. The cat is the biggest restriction on the stock exhaust, yet on a stock car that doesn't mean much. If you're tuned, you'll see a bigger gain. If you swap turbos, you'll see an even bigger gain. As someone else noted, cat vs. no cat isn't a big difference in sound until you put your foot down.

 

HELLASTOCK4life you need both cats for Maximum performance!

 

Lol this guy! That should be my user name. Sadly soon i will be removing my hellastock sticker. I just ordered the zzp catless downpipe and will be re installing the k&n intake.

It was fun beating cars and showing them the all stock and all plastic engine bay. Man the look of their faces was priceless.

Its hard not modding this SS

 

Well i iust installed my zzp catless downpipe. I put the stock muffler back on. Car is not loud at all. Stock downpipe and muffler delete was louder.

Im a lil disappointed becuz its so quit. I should have not installed the muffler.

 

Easy fix for that.... take the muffler back off. Lol....

 

exhaust shop will pull that muffler and weld you in a straight pipe for probably 40 bucks if you really want your car to sound like an SRT4.

 

I remember a test that import tuner did with 99 civic si. High flow vs oem there was a 3 or 4 hp gain. high flow vs test pipe, only netted 1 extra hp with the test pipe. So i would go with the catted just to not deal with the smell.


Catalytic Converters - Stock vs. Aftermarket Cats - Import Tuner Magazine

 

Lol.....comparing a civic si at 147 hp to a turbo cobalt ss. And i say again LOL!

Good article none the less, but we are boosted so im sure that snail loves a good straight pipe.

A respectable 147 hp lol.....sorry i just laughed when i read that. My Beretta GTZ makes that and i consider it very slow. And i have the dyno charts to prove it. All the honda boys were giving me props...i laughed inside.

Anyways yea i had the muffler delete but going off youtube vids i found the catless and muffler less sounded to raspy and ugly. Maybe it was all in the recording equiptment.

Well i already paid to reinstall the muffler, so it stays.

 

The point is about the cats not the car.

 

I didn't notice a smell with careless, only thing I don't like is the sound at aggressive part throttle sometimes

 

I vote for catted. Stop messin' up my air!