so this is my ongoing exhaust rattle story. first off, i have 97 EX -- d16y8 with intake, header, and 2.5 full exhaust w/ carsound cat and resonator. after reading the obx twin loop muffler review, i decided to to give it a shot.

i must say, other than the annoying rattle, i'm very pleased with the obx twin loop. it sounds great above 2500 rpm, so it really only gives me problems in 1st and 2nd gear. idle sounds slightly above stock and WOT sounds great.

the rattle sounds like the same rattle many others have had. it's a metal hitting metal kind of sound, but what's wierd about it is that it stops at 2600 rpms. it also gets worse as the engine gets warmer. you can hear a "quick" rattle when i crank the car or give the car gas quickly, but if i give it gas slowly, you don't hear it.

so far, i've removed 2 heat sheilds and checked the rest, as well as checking the spring bolts on the cat. i also had the local muffler shop replace the resonator, with no luck. after lots and lots of searching and reading how h-t people despise obx and love name brand companies, i decided to buy an apex'i ws2 universal muffler (which is for sale, btw). the ws2, compared to the twin loop is MUCH louder, though still not as loud as most straight through designs. it didn't, however, take care of my rattle problem. since i prefer the tone of the twin loop, i took the ws2 off and put the twin loop back on. my next step is to replace the carsound cat with a resonated test pipe. i'll give an update afterwards.

if anyone has has similar symptoms, thier input would be greatly appreciated.


ps. sorry for writing a book here, but i was trying to be thorough.

 

do you have a short shifer?? maybe its hitting it..i had a very similar problem..turn out my bolts from hearder to cat and catback were loose...

 

no short shifter and bolts are all tight. but the downpipe is mighty close to the oil pan.





notice how in the first picture the bottom pipe is straight and the second pic there's another slight bend. that's the exact spot where it seems as if it could be touching the oilpan. i wonder if that's where the rattle is coming from....

 

other things could be the resonator...but you said you already checked that off...no idea then man...

 

It's the muffler, just installed the obx twin loop and the rattling start to happen. Always on 1st and 2nd gear until i hit higher rpm like in the 2700, just like what you said. I have rack up and check it with another mech. Beside the rattle, the muffler does sound good, and it's not that loud, plus I don't have a resenator too. But planing to put one on. The only thing i hate is the tip sticking out too much, gogin to cut about a in out on the part where the tip connect to the muffler.

 

did you check the plate that mounts under the motor, cuz if that is rubbing together and not bolted in, the two brackets will rattle

 

I've gone through so many exhaust systems dealing with sound and rattle problems it makes your story look like a wonderland.

All the symtoms you state your problem might be either in your pipeing or your muffler.

First, is your mid-pipe/S-bend pipeing shapped like a squareish S bend, or is it more like the stock pipeing bend? I know ur ws2 (cause i had it also) is what im talking about. If its several pieces, try flipping the exhaust piping. Those S bends from bigger pipeing can be very annoying. But you would notice that on turns more then idle.

Or go with a piping system like the thermal stealth. Its exactly like the stock piping but in 2.25inch.

Second thing to check is your muffler hangers. Are any of them damaged? Is the hanger not sitting in the rubber correct? Also look and see above the tail pipe, the 2 muffler hangers, and look there. They might be pushed back because your running a different cat conv. I also had that problem. Some of these exhaust systems are made to be fitted up to a stock cat. And if an aftermarket cat is more then an 1/8 of an inch bigger+ the flange, it will push the hangers back causeing a rattle at the muffler.

I had the problem and i went back to the stock cat and it stopped the rattle. A ******* 1/8 inch bigger cat. That really pissed me off.

I doubt its your header though. Unless you did your entire exhaust system all at once, when did you notice the rattle? After what mod? And since the header is bolted directly to the engine, it moves with the engine, unless its lose. Check it for clearence and if you have it, its not the problem.

Good luck and sorry for the novel. I personally have like a 6 piece exhaust system from different companies. Nothing is better then full custom though.

 

do you have a sway bar installed by any chance? if so, is it close to the piping?

how's your clearance on the gas tank straps? i've seen some people rattle against those before.

 

ive had mine rattle too, and it only rattled when hte car was warm

check ur exhaust system for leaks, get ur car on a lift and turn it on. feel around the pipes for air leaks.

 

My evo hits my stock LCA's im going to add another hanger this weekend and pull it up a little higher.

 

thanks for all the help guys. i'm taking the car up to the muffler shop today and see if they can spot where the rattle is coming.