when I let off the gas and rpm's get down pretty low (like I'm in second and getting ready to stop at a stop light) I hear a rattle in the front? Sounds like it is coming from where the header and test pipe meet.

Everything is tight as can be????????

It sounds fine all the other times, but like crap when I get ready to stop???????

 

Damn, i had the exact same problem after installing mine. It makes this nasty rattling noise (sounds like my heatsheilds are rattling or something), but i checked EVERYTHING...and its all tite. Its really bad on the highway..and when im about to stop....

 

it's exhaust pulse noise. there is a resonance in the engine around 3K rpm (most noticeable with throttle-off coasting down a hill). nothing you can do about it except to put the cast iron header back on (you can still hear this noise with the stock exhaust system on - but much fainter).

 

what makes this happen with the test pipe, but not the stock cat?

 

the cat is a chamber of catalytic honeycomb - which tends to absorb noise more.

 

I just had this with my exhaust system. Is everything lined up? Make sure the exhaust is sitting straight on the mounts (and not tilted to one side or another). I know you said the sound is coming from the front, but a bad rubber mount near the back axle cause my bpipe to rattle on the shift linkage. When I heard/felt the rattle, I could have sworn it was way in front of me. How about the o2 sensor? Tight? Is it hitting the rollbar or shiftlinkage? Header bracket? Check, check again, and keep checking. It isnt rattling for nothing, something is out of line or not tightened... somewhere.

Goodluck.

Edit: Well... nevermind then. Wrong answer for me!


[Modified by 1107, 8:50 PM 10/9/2002]

 

so there is nothing to do about the rattle????

besides putting the stock stuff back on?

throw me a bone here or a beer

 

ok I'll check, it's just hard because I just had shoulder surgery so I'm a one armed bandit right now.

it is a 2.5" could it be that it is tooooo big?

the *** end could be to big and causing some back log of air?

 

does it look lined up?

 

No more spring bolts?

 

Catalytic Converter

Test pipes

Just my opinion. Don't worry too much if it is lined up or not as long as there are no exhaust leaks, you're good to go.

 

you think I should go back to the cat spring bolts?

could that be why?

it could be worth a try.

the ones that came with the test pipe are just regular **** so maybe that's it?

 

I'm having the same problem, but I hear mine when I'm on the throttle as well as off of it. The weird thing is that I only hear the rattle at around 3000 rpms. I don't think it is a resonance in the engine, it sounds like loose metal rattling around but everything is as tight and straight as can be

 

my stock cat rattle bad too. I took off all the heat shields and it still does it. cant wait til i get my exhaust and test pipe so i can ditch the rest of my stock exhaust

 

I think you need the springs back in there between the header and the test pipe. No flex = Bad. Maybe the header bracket is chattering at certain rpms because there's no flex like there normally is.

As for you Nate, I think you have another loose bolt like the one Dave found on Sunday. I'm almost positive of it, or it could be the header bracket. I didn't hear the rattle when I drove your car. I'm pretty sure the problem is the resonating causing some vibration, which is some bolt somewhere under there!!

 

Summummabitch, I can't find the little fuggin loose bolt. I was one mad cracker laying under my car for an hour looking for a fuggin bolt. My neighbors thought I was crazy with all the vulgar yelling that was coming out of my garage.

 

It's internal resonance - you can't get rid of it.

 

Instead of running a cat, or a test pipe, what about a real small resonator?

 

I've heard his rattle. It is definitely not internal resonance. It really truly is a mystery bolt, some obstruction or caused by something misplaced.

As far as testpipes, is it normal to have no springs between the header and test pipe???

 

I have the rattle too - I've always had it.

I've been through everything mentioned above. I've had a Mugen 4-1, then a Spoon 4-2-1. Still a rattle/buzz. I've removed every heatshield too. I use a Spoon catjack, header flexjoint and Mugen b-pipe and twin-loop.

The buzzing goes away when the exhaust system is fully heated - like at the track. On the street it always buzzes.

And so - I say it's internal resonance - you can't get rid of it.

 

I put the springs back on the bolts and put some sealant where they connect and it doesn't rattle anymore. Thanks guys