My EM1 has a stock exhaust and at regular street driving is relatively quiet. However, on the highway at high rpms/speed the exhaust just recently has become much much louder. I checked the exhaust and the catalytic converter and there are no visible holes anywhere.

Anyone know why my exhaust is so loud, is it the catalytic converter? Any other ideas?

Thanks

 

Most likely a hole somewhere in the piping or a gasket thats all worn out. Just gotta get under it and inspect all of it :/

Wisconsin weather sucks for things like this

 

you probably do have a hole somwhere where you cant see. i had one and i swear i checked like five times but we finally found it when it was put up on the rack

 

my DX had this problem recently and was only getting worse. the rear muffler was rusted out at the weld just before the muffler and it eventually worked its way loose

autopartswarehouse.com has a pretty decent deal on OE-replacement exhausts if that's what you're looking for. I replaced everything after the cat for under $150 and did the work myself (that includes a resonated mid pipe and rear muffler). Granted it's not stainless steel but it works and I probably won't ever have to replace it again. Meineke wanted $160 just to make a new rear muffler... lame

find the hole and get it re-welded for $20 at a local exhaust shop if it's a minor job. if it's a complicated job it'd probably be easier/cheaper to just find a used aftermarket exhaust on here

 

check where the piping goes over the rear lower control arm mine rusted threw on my em1 and sounded like nascar at 70mph

 

Now that it's getting cold enough, start it and look for the exhaust coming out. A little quicksteel should fix it for a short while.

 

x2

 

This happened to my brothers 240sx like 4 years ago. Like everyone said, check your pipings, there is a hole somewhere.

 

Haha bro you just over reacting. Its your vtec haha

 

lmao ^^

 

check the donut gasket before the "test pipe" area

 

Lmaoo. I never knew 240's came with Vtec. Haha.

 

Ugh ok who said we're talking about a 240? Look on the first post. It says EM1. And just in case you didnt no, an EM1 comes with a doch vtec motor. So nice try but maybe next time

 

Took apart the entire exhaust and no visible holes anywhere...still going to replace the exhaust regardless. Any other ideas?

 

Did you find anything with the cold weather test? Did you pull the heat shield on the header? You should see some black soot gathering around any possible crack in it.

 

hahaha, don't get mad, get glad

 

UPDATE: We would hear a loud humming noise when we drove around 30-40mph. Thinking it was the exhaust we replaced it. It was not...turns out it was actually the right rear wheel bearing that was causing that noise. About a $100 fix.