r3p00c

hey guys, hopefully one of you has had, or has heard one do this before. i went through hell and back to get this apexi ws2 to fit properly on my hatch. when i got it, the midpipe was too short and needed to be extended to reach the cat. it was being pulled forward and hitting parts of the exhaust routing.

i ended up bending back the lip of this part that was hitting, as a member of honda-tech recommended:



that didn't solve the problem completely, it was still hitting the gas tank. on top of that, it started making this really strange sound at certain rpms... its almost like a high pitched hum that fades in and out.

i took it to a shop, and they cut the midpipe, welded in a piece of stainless as an extension, and adjusted everything else, so nothing at all was hitting. drove it home... and i still get that weird hum sound that fades in and out at particular rpms.

so... what could it be? an effect of bending that lip back? a defect in the ws2? i doubt that i could get apexi to replace it at this point, since it was modified to fit the car (although it should have fit just fine out of the box). all i know is its very annoying, and not a sound i expect to hear after spending $400 on an exhaust and $75 having it modified to fit.

can anyone reccomend what i should do at this point? thanks for your help!!

r3p00c

just figured i'd also add that the heatshields have been removed since that pic, so thats definitely not the problem.

Relic1

Bending that lip wouldn't do much. it looks like the inner mount for the trailing arm toe arm. Not a huge deal as long as the arm isn't hitting the lip.

make sure all the mounts are at least 1/2 inch or more away from metal contact. Also if you have a lower front tie bar make sure your header isn't hitting it. Remember under load the engine rocks back a little.

I'd just get under there and grab the exhaust and shake it, if it's hitting something you will notice it easily.

the hum also could be resonance of the exhaust tone vibrating something inside the car also...

r3p00c

thanks for your response. i had the people at the muffler shop that did the extension show me everything before they put the car back down... i shook the exhaust and nothing was hitting, but you're right... maybe it could be moving back far enough so its barely touching something and making that hum under load...

there are no other aftermarket parts on the car yet, so thats out of the question.

i don't think it could be something in the car, unless its my spare / jack doing it... i'll take all that stuff out and take it for a ride to see what happens. couldn't hurt to try!

95IntegraGSRAZ

I have the old school world sport... it makes a humming noise certain rpms... never effected anything that i can tell, think it has to do with resonance produced by the exhaust flowing threw the system... mines has done it ever since i bought it 2 years ago... just sounds like a humming noise, usually not under WOT, last threw about 4-600 rpms... more just city driving (lower rpms)..... idk just a thought