Ive been trying to bust my exhaust that sounds like crap syndrome for a while now. I thought it was my flange leaking behind the muffler, so today I rigged up a device that allowed me to rev my motor while I was underneath so I could listen and feel for leaks. The flange was NOT leaking, but I was hearing a horrendous metal rattling sound that also is heard when the engine is above 5000 RPM or when decelerating lift throttle and in gear. The sound is definately coming from within the muffler.

My setup looks like this. Stock manifolds to Cattman Y pipe, to stock cat, to Stillen B pipe to stock muffler to 4" non-resomated tip. Im going to try to make a mp3 recording of the sound. Another interesting note is when I had the OEM Y pipe in place it did not make this noise. What the hey is goin on? I wonder if my muffler is either a) goin bad or b) this is the nature of the Y pipe and resonatorless exhaust. What does your guy's exhaust sound like with a similar setup?

 

Eric-
Mine makes a similar noise. or atleast I think. I've taken my car to 5 places now, and they've all told me similar things... that the muffler isn't bad, but we are exceeding the flow rate of the muffler. thats what gives you that awful noise. I'm not sure if I believe that or not. But thats what whitemarsh muffler,meineke,midas,HP racing,and tony's custom exhaust and muffler have all said. So I guess I'm looking at a Flowmaster 40. It's a baffled muffler so I'm hoping for decent flow and little to no droan.

 

If you had the liberty of trying out a different muffler, that'd be nice to see if your symptoms went away.

How long ago was it that you had the OEM Y in, and at that time did you have the custom 4" tip on the OEM muffler setup? How's wear on the muffler?

 

Yea that would be great, except I've had this rattly exhaust problem on any vehicle I've either put a Y pipe on (maxima) or a header on (my old camry haha). On the Camry the same thing happened when I put the stock manifold back in, it tamed all the loud harsh metallic sounds.

I had the OEM Y pipe on only a few months ago while my cattman unit was being repaired. The muffler shows some surface rust but it seems to be holding up OK.

Oh yea, and the metal that sounds like crap sounds get quieter when the car is warmed.

 

I had the same problem when I was running a test pipe in place of the cat (also y-pipe no resonator). Not nearly as bad with the cat back on, but still there. Are you talking about the Bees-in-a-can sound coming from the flex section on your y-pipe?

By the way, SLC I30: I think a 40 series might be too loud. Im running y-pipe, cat, no res, and a 50 series and its loud enough. I set off car alarms half a block down the street. (then again, a 40 series might have a different/nicer tone...)

 

I thought that the 40 series was quieter than the 50 series.

 

Nope, the 50 series is a 3-chamber while the 40 is a 2-chamber. Also you can get either delta or non-delta flow. Delta flow is quieter (has some added baffle system that is supposed to flow better).

BUT, on a V8 car, the 40 series non-delta flow, although loudest, sounds the sweetest....didnt want to risk it on a V6 tho, but you can

 

I have the eXACT same problem.

When you're sitting in the car with the door closed, it sounds like there's a screw somewhere sitting on top of your engine when you rev it.

After first hearing this, i had ebmorgan listen to the car while i revved it.

He said "Man, that's not coming from your Engine, that's coming from your Y-Pipe!"

IanS

 

From reading other threads, I think its coming from the flex section. Wrapping it in header wrap should help the problem. Im going to do it this weekend, we'll see how it goes....

 

Thats why some of us bought lined flex sections. If you sit under your car and have someone rev the engine you can hear the origin of the noise... it may be a bad flex, but in my case I know its the Muffler we threw it on a stock car and tried it... sounded fine.

 

Mine is wrapped....

It doesn't help.

I think it may actually be the metal O-ring gasket rattling around.

I took it off about a month ago and inpected the inside with a flashlight. No obvious light shown through, and it looked fine.

I'm going to take it apart one of these days, re-wrap it and replace the gaskets, like I probably shoudl have done when I took it apart last time.

IanS

 

Well u all know how the y-pipe increases noise of the exhaust espectially w/o a resonater. just throw one in and the noise will be gone. i had that noise w.o a res, now i have one and the noise it gone period.

 

Not sure what you mean. The car's exhaust system has a resonator already.

 

the stillen b-pipe doesnt have a resonator. i have the stillen y-pipe stock cat and when i had my resonator removed i had the same exact noise with the stock muffler. if u have a stillen b-pipe then there is no resonator. i threw the cattman b-pipe which has a resonator and i no longer have any noise even close to that. with the stock muffer and the exhaust modded it was just a bit deeper at idle and quiet form there on.

 

Ummm....I have a Stillen B-pipe.


With a Resonator.

The person who gave it to me had 2. One with, one without.
I took the one with, and physically saw both.

IanS

 

im not gonna argue with u man, im just tell u what i know from what happend with my car and the noise similarity. my car is a 5th gen which i dont think would make that big of a diff in the exhaust noise, same motor. but if u do have a resonator and the stock muffer and its makin that noise i dont know what to say about that rattle. all i know is the rattle from my car is gone and i was just tryin to help out with some info, but hey u cant say i didnt try. goodluck man, later.

 

I don't think its a resonator issue, I'm conviced that its a flow issue. Assuming its coming from the rear of the car I mean. If its a Y pipe thing, then go to your local exhaust custom shop and have them replace the flex with a lined flex. But Stillen and WSP sell their B pipes with and with out resonators. They are considerably smaller though.

 

You should try to swap a muffler with somebody and see if the noise goes away. Or maybe just take the muffler off and see if the character of the noise changes. It will be loud as heck but it may help determine the source of the problem. It is possible for internal muffler parts such as baffle plates to come loose, and they make a lot of racket when they do.