I started with the stock SS exhaust, then upgraded to Corsa catback. Now I have installed Hooker LT's with the Hooker y-pipe and no cats. Besides being loud as hell, I notice that I get a loud resonance from 2K-3k'ish RPMs in every gear if I stay in that RPM range.

Any one else notice this?

I checked for leaks and so for so good.

Man these were so much easier to install than my LT1's headers!

 

What your experiencing/hearing is known as the famous LS1 RASP without cats. Any cat-back will do this with off-road pipes(some worse than others). Putting on highflow cats will get rid of it. If you don't want to get rid of the orp's, you could also put a Dynomax bullet muffler in your I-pipe which would help a little but it'll still be noticeable.

Mike

2002 M6 Z28

 

omg ya thts anoyying......i sold loudmouth and got borla with dynomax bullet muffler

still waiting to get installed tho

 

So re-installing cats would be the only way to solve this

Screw that.....I'll wait 4 years till it's smog test time.

I wonder if cat back makers could re-design their resonance chambers to deal with the no-cat scenario?

 

Xnight, got the SLP LT's with their Y-pipe, no cats.. I get the "rasp" when shifting, lifting off the gas. At steady speed, no rasp. Mebbe it's just the car, dunno...

 

Nope, that's just how mine is. On the gas it rasps from 2-3K then it's just loud as hell. However at 2-3K RPM if I lift the pedal it does not rasp.

Just wanted to know if that was normal....sounds like it is, thanks!

 

xkhightrider, i had a 99z with mac midlenght headers nocats and a flowmaster cat back. it made a horrible rasp at 2K to 2500 . i put a resonator in line it helped but was still there.

now i have a 02ss with slp longtubes and no cats but with the slp dual dual exhaust and let me tell you that exhaust is unbelieveable it is so quiet but still sounds good under mid to full throttle. i'm really impressed with the exhaust

other than that ,every ls1 that i know of with no cats makes a noticable rasp. hope that helps you