my '87 350tpi has dual exhaust from cat back, it has an excellerator muffler and big chrome tips, also the cat was cut off so it doesnt have one at all.
my question is why does it sound kinda raspy ? i like the low tone it has in the lower RPM range but i'd rather not have the rasp sound, what could i change to make it have just the low rumble sound?
thanks

 

Put a high flow cat on

 

can't afford one

 

The raspy sound is most likely due to the cat. Thats how mine sounds too when the RPMs get up there cuz I have no cat.

 

how big are your exhaust pipes?

seems like smaller exhaust pipes tend to cause raspy exhaust sounds......

 

Well that seems to be the cheapest route to ridding of the rasp.

 

If you have real dual exhaust, you can install an H-pipe, that will get rid of the raspy cackle sound. I installed an H-pipe on one of my cars, I was already happy with the sound, I installed the h-pipe to see if it would squeak more performance out of it and it ended up taking the raspyness out of the sound, unfortunately it did nothing for peformance in my case, but thats another story, Larry.

 

the exhaust is 3" and the tips are probably 4"X18"

 

hmmm well u definately don't have small exhaust pipes so it must be one of the other things....

 

i was wondering if i could buy a glasspack that would fit where the cat was, would that not work just as good as a high flow cat?
any suggestions would be good. thanks

 

you could buy a dynomax bullet or moroso sprial flow muffler adn put it where the cat was....for under 40 bucks, that should fix the problem...

 

A hi flow cat costs like $40-60.

 

never seen one that cheap...

 

universal cats are cheap... carsound/magnaflow can be found for 30-50bucks or so. the ones custom fit for the cars are like 110bucks. LOL

i had abit raspy sound with my flowmaster catback. with cat too. once i put on my hooker headers, it went away and became deeper LOL

 

cutoff the exhaust, the raspy sound tends to go away...or maybe it gets drowned out

 

"Catco universal catalytic converters not only out-flow stock converters, but they also offer great features."

Summit # CTO-6906R
2.5" universal fit.

 

ok, thanks for all the input, so i need the 2.5" not 3" ? or should i check before i buy anything.
another ? is isn't a cheap glasspack only about $20?

 

yea, i'd go with a bullet muffler tho...glasspacks might just add to the raspy sound...if its stock pipe size you need 2.5", if its aftermarket its more than liekly 3"..

 

do you really thing a glasspack might add mor rasp?
the bullet muffler is about $35, now i am getting close to some high flow cats on e-bay. that reminds me what would a resignator do for the rasp? they claim that they will give you the low tone. what is your thoughts? thanks

 

a bullet is basically a a resonator...glass packs are packed with alot more fiberglass than a bullet or resonator...so the glass in a glass pack are made to catch air and make that sort of popping sound, and that adds rasp...listen to a truck with glasspacks, sounds pretty raspy....go with a bullet, resonator (maybe like an SLP or something) or a highflow cat...

 

i am not shure if my car could get any raspy-er. its pretty bad, i mean it would sound pretty good on a 4x4 pickup or something, but a camaro is supose to soung mean and low. just my opnion.

 

Refresh my memory, what is that exactly?

 

maybe like a moroso spiral flow??? that might accelerate outflowing air, hence the name "excellerator" or how ever he spelled it

 

thats just the brand of muffler that Performance Exhaust (an exhaust shop ) puts on unless you want some other brand.
my chevy truck has the same thing on it.

 

on my old car I had a borla which started getting louder after several years. even with the one side blocked off it ended up sounding like those pos TBI trucks that run no muffler (well if it reved super slow and bogged when it up shifted). then I decided to try the slp catback 2out on drivers side, man what a differance it got rid of all that cheap raspy f-body noise.


I can't stand the flowmaster on a single exhaust (still has all that nosie but, you hear it poping and crackling in the muffler like a hollow can)


now my next question is why have true dual from the cat back but, not all the way? IMO it is hard to find a car that sounds better than a true dual flowmaster v8 with headers mmmmmmm


I have personally decided that the slp cat back = good for our f-body cars

and if you can run duals go for flowmasters

 

As someone said, it's from the fiberglass packing in the muffler.

My Dynomax Super Turbo, single inlet / dual outlet does this if I rev it without a load on the engine (in neutral or park).

It's never done it under a load though.

The sound is actually little backfires in the muffler. The fiberglass gets coated with carbon and it POPS every time the fiberglass gets hot from the carbon getting hot.

Pretty much the same way metal pops when you're welding if you don't clean it first.

 

I know all this but, my point is a good muffler makes this noise almost unnoticable.

look at my slp that does not pop at all! (it is old now and still sounds good) seems like trucks and f-bodys cars (all single systems) sound like trash with 90% of the sytems out there