Magnaflow O/R X hissing

Hi All,

A year and half ago I installed a complete (O/R X and Catback) Magnaflow system on my '02 GT.

Ever since I put it on, there has been a somewhat loud hissing. It sounds like a "Tssssss" when I'm doing anything except for VERY light acceleration. I had originally thought it was a leak, so I had the catback welded. It was still there.

Put the car up on the lift and they could still find no leaks and I couldn't hear any either. It seemed to be ONLY when the car was under load. So, out of desparation, the muffler shop welded the mid-pipe to the catback as well. No change, the sound was still there..

I took it to another shop the other day and they said that X pipes will sound that way. I havn't heard that before, so I turn to my trusty Stangnet Forums and I see there are many other people having similar issues. So, if that's just the way they are, then I can accept that. But - I must say, it sounds like crap.. I've lived with sounding like an old dump truck for a year and a half, but I can't take it anymore!!

It's especially bad when I'm accelerating between two vehicles at a stop light.. I can hear the hiss echoing off the vehicles around me and it sounds horrible..

My question is: Is there anything that can be done to eliminate/reduce this "hissing" sound? I was thinking of using some header wrap on the X in the X-pipe. Has anyone tried this before?

Thanks!!
Riley

helty said:

need more descriptive info. was it like a metallic howl? i have that sound after installing my bassani c/b. almost sounds like my d/s and mufflers are rubbing, but thats not the case or it would be a lot more than just a sound.

Click to expand...

Sure thing.. I'll try..


You know the sound you hear when your listening under the hood of a vehicle with headers? Like the sound of the exhaust pulse hitting the metal of the pipe? It sounds somewhat like that..

It's like a *VERY* metallic tinny, high-pitched *ting* along with a little *shhhh*..

Haha.. if that makes any sense at all....

Thanks!!
Riley

helty said:

yeah, that helps. It sounds a lot like mine does. Do you have any clearance issues with the driveshaft and mufflers? My mufflers were very close to the driveshaft when we installed the cat-back, but were not rubbing. If they were rubbing it would be obvious, but maybe they're close enough to cause that sound under load when the driveshaft is spinning faster compared to lower rpms. Just a wild guess

Click to expand...

Nope, no clearance issues I'm afraid.. I've looked at the driveshaft and there are no wear marks.. It's all an even rusty color..

What do you guys think of using header wrap on the x pipe? I think it would server to at least diminish the sound.. I'm willing to at least give it a try..

Thanks!!
Riley

SOLVED!!

Well, on Saturday I decided to go out and pick up some header wrap. I checked Autozone, and a few other places, but noone had any. So, I took a trip down to Summit Racing and bought a 50' x 2" roll of the Black DEI header wrap and 8 Stainless zip ties.

The instructions say that the stuff is easier to work with if you soak it first. So I soaked it in the sink for an hour and then went to work..

I ended up using the whole 50' roll on the x pipe. I wrapped about 8" before (up to the O2 sensor) and after the X and I went over the X two time. Tied it all off and took it for a spin..

Now I'd say the noise is 90% GONE!! Ther is still a VERY light "swish" when I'm starting out, but that's it!!

So, it looks like the problem all along was just the exhaust gasses resonating in the X pipe.. The header wrap seems to muffle it.. FINALLY!! After almost TWO YEARS I can enjoy my exhaust and not have to worry about tippy toe-ing it around to keep it sounding like an old dump truck.. AT LAST!!

<sarcasm>Too bad I had already ordered a set of MAC Ceramic LT's from partshopper in the hopes of it fixing it.. Oh darn.. </sarcasm>

Thanks!!
Riley

My Summit invoice says...


DEI-010108----EXHAUST WRAP BLACK-----$40.98
DEI-010202----LOCKING TIES 14" 4PK------$15.90 (x2)


If I were to do it again, I would have gotten two rolls and done further ahead and behind the X. I would also have put another couple of layers on the X.

Thanks!!
Riley