High flow cats or a 2nd muffler for rasp?
 

I posted in performance trucks but havent gotten much response plus I know a lot of people here have had tons of experience with different setups. Anyway here in a couple weeks I am going to be putting on my Corsa Sport muffler and Pacesetter Y pipe on my 03 Silverado SS. I'm changing from 3" true dual (previous owner) to a single 3". From my reading I see that people say they get a lot of rasp with long tubes, no cats, and Corsa so in my opinion I would like to get this right the first time and not have to hack up a perfectly good exhaust later. My question is what would my best option be? To buy the high flow metallic cats or put in a 2nd muffler, a powerstick to be exact. I'm trying to get rid of the rasp but not cut down the sound of the cam too much. By the way I can get both for around the same price.

Go with resonators is youre best bet i think.

Don't they burn out after a while and be just as loud? Plus from what I read they would quiet more than I want them to. This is merely what I read because I have no experience with them. Heck I haven't had cats on any of my vehicles in 13 years.

Yea i cant really speak from experience either, i just think it woudnt be much better running 2 mufflers

2nd muffler would probably be better/cheaper.

What do you think is the source of rasp? Better to kill it there
than depend on some deadening to eliminate it altogether.

My belief is that "rasp" is from sharp edges in the stream. I've
seen some crappy transitions on cats, Y-merges and so on. A
rasp-creating feature downstream of the cats won't be helped
by cats, and so on. But a little time spent with a ball stone and
die grinder could do the trick, cheap, if you can find it by eye.

Borla(40085) , magnaflow(14419), or dynomax(24248) bullet muffler, or a QTP(12300) oval, but you'll need to know your placement options and how much space you have to work with first. Price range is $67 to $130.

Well I found some magnaflow 59959 high flow cats for sale, used for about 2000 miles. It's either gonna be those or a classic chambered powerstick muffler. Both are about the same price but I just don't wanna throw one or the other in and kill the cam sound.

The powerstick doesn't help. Not sure about cats. I heard they do but can't say from first hand experience. I think I'm going TD's anyway...

Power stick removed 95 percent of my rasp and didn't change sound very much

I put an LS1 in my '03 GMC, put in a small H&C package, LT Headers and a tune. Truck made 312 @ the wheels.

My exhaust is 2 1/2 duals from the headers into a Magnaflow dual in/out muffler and duals out the back. There is NO RASP.

The rasp comes from forcing 6" of combined pipe (3" headers) into a 3" pipe and mufflers, resonators, cats, whatever. Why add all of that when the reason for adding headers is to let the motor breath? I took 6" of pipe and reduced into 5" and added a dual inlet/outlet muffler (X pipe theory) and duals out the rear for a sharp, crisp, roaring sound that beats any high HP motor with a y pipe.

Buy a dual in/out muffler, go to a muffler shop and have them build an exhaust for you. Its cheaper then buying a cat back, Y pipe and cats.

Chad

That motor was in my car with a bigger cam. Made 420.

I had Kooks headers and a Kooks Y pipe, cats and Stainless Works Muffler with duals out the rear.

It had RASP and I installed a Bullet muffler in the 3" section that toned it down some but was still very anoying.

Chad

I decided to go powerstick after the merge in the Y. Next week I will get it all installed and see how it sounds.

A lot of people have success eliminating rasp by replacing their craptastic merge with a nicer one. Flowmater, magnaflow, and a lot of others make nice quality merges.

Here is a magnaflow version for example. http://www.summitracing.com/int/part...0798/overview/

Thought about getting a different merge for the Pacesetter Y pipe but the one for trucks doesn't look bad. I'll see if I can get a pic of the inside later today.
http://pacesetterexhaust.com/off-roa...5-72c2265.aspx

That merge doesn't loo too bad. How the inside looks will tell the tale though.