Stock mufflers, has rasp, suggestions to fix??

[jmgtp]

Been a long time since I've been on here and probably even longer since I've driven the Grand Prix. In the past year I bought a condo and a corvette and those two things have been getting all my attention. The Grand Prix has been sitting patiently in the garage. Amongst my plans for it is an LX9 swap which I already have the motor and the vast majority of parts necessary, I just lack the time to get it done. My goal is to make it a reliable driver rather than its former occupation as weekend toy. But for now, I just want to get it back on the road for a few months before I swap motors hopefully over the winter.

Three things on my immediate list before it is roadworthy are:
Quiet Exhaust
Replace Front Wheel Bearings
Fix Power Steering Leak

I'm on step 1, quiet exhaust. Cars this loud do not fly in a condo complex, whiney neighbors and fines just arent worth it. Gone is the beautiful stainless steel 2.5" system I built. In its place, downstream of the cat is a moroso spiral flow to act as a resonator, the stock y pipe and a set of mufflers off a 97 Grand Prix out the back. It is pretty darn quiet now. By no means new car quiet but 1991 quiet. Problem is that I got a bit of that nasty metallic zingy rasp - I remember this from the bone stock exhaust way back when. What do you guys do to eliminate it? Do I really need yet another resonator of sorts in there? I'm tired of welding at this point and I hope not. Does that clamp on weight do anything (I have it somewhere)?

[pocket-rocket]

I think that weight was supposed to get rid of some sort of resonance that helped create rasp, from what I was told. The 92 has a small what looks like a glass pack before the Y and it doesn't have a whole lot of rasp (from the little bit that I've heard it driven without me in the car).

[RedZMonte]

yep, adding a glasspack before the Y is the easiest option to quiet it down a little more. I used a 4" round magnaflow and it does a good job, compact and made a noticable difference vs no res. LQ1's are a raspy motor, they like to make noise

lol a turbo would also quiet it down and clean it up lol JK

S

[jmgtp]

I ended up re-doing my work - I just wasn't happy with how it turned out. It is still a frankensteined system, part 91 Grand Prix, part 97 Grand prix and part aftermarket, welded together into a new beast. The change I made was I used the y pipe and mufflers from a 97 Grand Prix, my existing high flow cat and the moroso spiral flow right after the cat. It sounds much more reasonable now. Still not deadly quiet but pretty quiet at idle and not buzzing anymore, havent rev'd it up much or driven it (its currently dead - see other thread regarding crank pulley prob). I imagine at full throttle its still going to sound pretty awesome. It actually sounds a lot like a bone stock 3.1 does at idle. Reminds me of my old beretta. Now to resolve this crank pulley prob...

[Driver_10]

A set of decently built, "semi" equal-length headers would do wonders for sound quality by smoothing out the pulse harmonics. A good "absorbition" style muffler (by that I mean a glasspack or stainless packed resonator/ muffler) would help further reduce some of those nasty frequencies as well.

BTW Im too lazy to search for the thread, but look up "fiero with interesting exhaust" (or something like that) through the thread search. It wasnt too long ago that there was a discussion about this.

[jmgtp]

A set of decently built, "semi" equal-length headers would do wonders for sound quality by smoothing out the pulse harmonics. A good "absorbition" style muffler (by that I mean a glasspack or stainless packed resonator/ muffler) would help further reduce some of those nasty frequencies as well.

BTW Im too lazy to search for the thread, but look up "fiero with interesting exhaust" (or something like that) through the thread search. It wasnt too long ago that there was a discussion about this.

I'm sure headers would be great sounding but I'm going in the other direction with this car: de-modding. I was reall happy with my prior exhaust setup that I had built. It was a 2.5" stainless steel system from the downpipe through the highflow cat and moroso spiralflow and then into an 80 series (yes an F body muffler) flowmaster tucked between the suspension and spare tire well. It was honestly the best sounding LQ1 I've heard. A really V8ish idle and a screamer in the top end, didnt rasp or buzz one bit. But this car is no longer my toy and it was rather loud (got a neighbor in the condo complex that likes to complain) so I decided to make her quiet again and I'm swapping an LX9 that I have over the winter to make it a torquey, smooth and dependable driver.

edit: I see you're doing an LX9 swap too! Cool. If you havent purchased the motor yet check out LKQ. I got mine for $300 and luckily they had it only an hour away so I just went ahead and picked it up to avoid shipping costs.

[Driver_10]

Ha ha! Thanks for the advice.

[ForcedFirebird]

John got his lx9 from a good source as well

I have stopped using LKQ, they have been charging me for cores and had a few sitting in the back of the shop they never came to pick back up. I have a much more solid source that usually is at least $100 cheaper than the rest, which balances out with thier $75 delivery fee (but no core charge). LKQ doesn't charge delivery to a shop, even though they are over 100miles away from me