I was going to get a 2.5 catless dp fabbed up at a local muffler shop and the guy said the restiction is most likely only in the cat, and that a test-pipe should give me nearly the same results. Can anyone confirm this?

 

A 2.5" catless dp and a test pipe are the same thing.

 

No... by test pipe I mean taking the dp off, cutting off ONLY THE CAT, and then welding in a section of pipe. Still using the rest of the stock piping, still using the stock flex pipe and flanges. Sorry if I wasnt specific enough.

 

uhm, yeah, thats what a catless downpipe is. its just one solid piece and not fabbed together.

an after market catless dp will have the stock diameter, flex pipe, and flanges

 

ok..your DP is 2.5" EXCEPT where it bolts to catback it goes to 2.25 Just cut that part out and weld a 2.5" peice. Our cats are not restrictive enough to notice a gian with catless and hi-flow work just as good as catless. Going catless is pointless to me.

 

oh, my bad. No the restriction isn't JUST the cat. Did he take a look under the car? If he did, he wouldn't have said that. There's a huge pinch in the stock DP where it bends to go to the rear of the car. That's also where the o2 sensor is. You need a whole new DP to see the best gains. Make sure the piping they do is Mandrel bent, NOT PRESS BENT. 2.5" dp is perfect.

 

Well I know I'm pretty sure its been proven that a dp can free up another 6-8whp, so.. I'm pretty sure atleast some of that is from resitrction in the cat, especially seeing as a few people have clogged their stock cats. And why dont I egt a hi-flow cat? Costs money and needs to be ordered, I can get my buddy to weld in a test pipe for free as long as I bring a few beer over this weekend, lol.

I'm sure my stock cat is half-clogged allready from this pig-rich stage 2 tune. Unless I can get the local shop to fab me a dp/header combo, this seems like the best idea for now.

 

get in on the zzp midlength header/dp groupbuy

 

There's a huge pinch in the stock DP

 

That's just a cat delete...

A test pipe is a bolt on cat delete as far as I know; you replace the test pipe with your cat for emissions then take it off after passing. The only problems with a test pipe is the possibility of flange leaks but if your welding that's not an issue. If you cut where the o2 bump is then it would probably be cheaper and a decent but loud upgrade.

 

the car is going to sound like absolute **** with just the cat cut out of it. trust me i was in a hurry to buy a real catless dp. i only did it to my car cause the stock cat got clogged. please do yourself a favor and get a real dp

 

I have no cat.. with a 3" dp... get a resonator welded in.. its the best thing you can do and it makes 85% of that raspy sound to go away (it did on my setup anyway... and not exaggerated)

The thing your thinking of where the pipe stops is a exhaust cutout... Very loud and wont do much for 4 bangers.

test pipe are pipes straight back.. nearly no bends (if possible) w/o a cat...

 

Not thinking of a cutout, just cat delete as neelster said. I dont want to order a dp, beacuse I dont order things online. I dont have a credit car and I dont want to connect paypal to my bank account(paranoid). How much should a resonator small enough to be welded into my dp cost and would a normal muffler shop sell it? What kind of raspyness would I expect from a cat delete? I know hollowing it out is supposed to sound like ass, but is it that bad if I just put weld in a section of pipe the same size as the rest of my exaust?

 

dude it sounds so bad its not even funny

 

its really not that bad.. ill record my audio and send it to you

i got a 18 or 20 inch resonator welded in for 70 bucks.... You will expect ALOT of raspyness unless you get the resonator... It will sound just as bad... and im telling you.. the resonator is AWESOME.. you have no idea how much this helped me.. i really didnt expect it to do what it did... thats seriously how much it helped..

 

you have the clear image combo. he is talking about going catless on stock downpipe. it sounds like ass. trust me, i did it

 

lol... ill take your word for it..

resonator ftw though....

 

bBw, what kinda cel's will I get and how can I get rid of them wihout hptuners. I know a scantool will clear them but unless I get sometrhing to trick the sensor it'll just pop right back up right?

 

Sure will.. To be honest i dont even have my 2nd o2 sensor hooked up.... And hptuners and one other thing i think will clear it... you can kinda trick it by using some washers and such.. but it only sometimes works...

 

So you unhooked your 2end sensor? Will that work even without hptuners? I dont want to tune my car unless I get a 2end ecu to tune and keep my stock one for warranty; and what does everyone mean by raspiness? anyone have a video to show me what it sounds like?

 

raspyness = honda riceburner sound

it works perfect for me.. i just throw a code every time the car turns on..

 

does it stay on? I guess I'm gonna need a scantool or just get the aeroforce scangauge so I can clear the code?

 

the code will just keep coming back everyday...i have gotten so used to the check engine light that it doesnt bother me. if you want, go to your auto parts store and get 2 spark plug anti-foulers and screw them together. now drill out the center a little bit so the o2 sensor can screw in. you have a good chance of this not triggering the CEL

 

Does the stage 3 ecu get cel from this too? Since its " for off-road use" according to gm, would they have designed it to throw a code for that? I'm thinking about buying one soon.

 

im pretty sure it disables the rear o2 sensor. im just not too fond of the stg3 pcm cause the tune is locked