I have recently turbo'd my ls and I am now in the process of trying to get all the little details worked out befor I send it out for tuning. I am looking to replace my high flow cat with a test pipe. Are the gains usually significant by doing this, or have i already made the right choice by going with a high flow cat. By the way it's a Catco High Flow.

Thanks

 

Just run no cat like me bro. Way more power I run straight pipe from turbo to exhaust

 

sounds good to me. I am in the process of buying a Omnipower Test Pipe. What type of test pipe do you guys run?

 

scew test pipe bro. Im running no cat or test pipe. turbo downpipe down to 2.5 inch exhaust

 

straight pipe

 

wouldnt a straight pipe all the way back be very loud?

 

Not as loud as you would think, the turbo quiets it up pretty well. I'm running a 3in. downpipe into 3 in. resonator, and a 3in. black vibrant oval muffler out back.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KRWTEK1 &raquo;</TD></TR><TR><TD CLASS="quote">wouldnt a straight pipe all the way back be very loud?</TD></TR></TABLE>

what do you think a test pipe is? its just a pipe with 2 flanges to replace your catalytic converter.

if you want something to quiet the sound a little i think they sell some test pipes that have a resonator in them. it might help a little on the sound.

 

Trust me bro its not loud. I run one resonator and its quiet until vtec screams

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sc4dr &raquo;</TD></TR><TR><TD CLASS="quote">Not as loud as you would think, the turbo quiets it up pretty well. I'm running a 3in. downpipe into 3 in. resonator, and a 3in. black vibrant oval muffler out back.</TD></TR></TABLE>
Have any sounds clips?

 

turbo cars have a different tone, just run the down pipe and connect it to the exhaust

 

how does one pass inspection without a cat?

 

screw cali smog. Here is clip of my dyno run with ls vtec turbo no cat, straight pipe with 1 resonator
sorry about the crappy quality , it was from my camera

 

2 resonators ftw. My full 3" dp/exhaust w/18" and 24" resonators sounded a tad louder than my NA/stock b18b1 w/apexi WS2 exhaust, which is very quiet (baffled muffler). Its more like an angry growl w/prominant mid-tones, but eliminates any raspyness. Only sound I like better is a built NA b18 with huge cams and quiet exhaust.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KRWTEK1 &raquo;</TD></TR><TR><TD CLASS="quote">wouldnt a straight pipe all the way back be very loud?</TD></TR></TABLE>

yes but if you plan on making any amount of power with turbo then youre going to burn the **** out of a cat due to hight temps. might as well go with a test pipe/straight pipe.

 

you can run high flow cas on built na engine no problem and will only lose a few hp
but on turbo cars cats high flow or not are huge restrictions and will cost youlots of hp. plus you cant run race gas on cats. it will just blow the inside of the cat apart. in real high hp motor will just blow the car apart.

 

I am either going to fab up a test pipe using the flanges off of my catco cat or I will purchase one. I would run 3 inch but my down pipe is only 2.5 inch.

Thanks for all of the responses.

 

Does anyone actually have dyno plots with cat then without cat? I don't want conjecture and heresay, I want to see some proof. I'm particularly interested in setups around the 300 whp mark. Don't tell me 'well it makes sense' I understand why the test pipe should increase power...I just want some proof.

 

If this is a street car, I'd really hope that you would run a cat. There is no need to produce crazy emissions for 10 extra hp on a street car, that hurts everyone IMO.

 

how can you pass inspection without a cat?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aaroboost &raquo;</TD></TR><TR><TD CLASS="quote">how can you pass inspection without a cat?</TD></TR></TABLE>
you cant

 

I have SEEN dyno's around the net comparing stock cat, high flow, and test pipe. The stock cat obviously restricts, but the high flow even in higher HP applications don't restrict much at all. Use google to searhc I'm sure you'll find some.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aaroboost &raquo;</TD></TR><TR><TD CLASS="quote">how can you pass inspection without a cat?</TD></TR></TABLE>

I have only a resonator (love the tone by the way, you can see it in the vid in my sig). I EASLY passed emissions check on a thread I made a while ago....I passed with flying colors on the rollers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceball777 &raquo;</TD></TR><TR><TD CLASS="quote">
you cant </TD></TR></TABLE>

maybe not in CA, but otherwise it's very easy

 

Go with the test pipe and resonator to quite it down some.

 

I dont think it matters as long as its the same size as your exhaust. No cat may pick up a few ponies but nothing thats will make your jaw drop.