I recently posted about my cat problem on my hatch. With 96-98 hatches, the cat converter is mounted directly on the header. So when I took off the stock header and put on an aftermarket one, I lost my cat.

Recently, I bought a used LS teg cat and a used SIR cat back exhaust. Both bolted onto my hatch perfectly. The only modification I had to do was to dremel off the tip of the exhaust pipe by about 3" and also to bend the hangers on the muffler back.

The new exhaust on the car is like night and day. I can actually feel the extra power and shifting feels more forceful.

Anyways, the slight problem I am having now is a slight vibration in the car at crusing speeds. When I am light on the gas pedal, a vibration in the car much like a rumble in your stomach starts to occur. I haven't had a chance to double check all the mounts and bolts for tightness, but would that be the problem at all? Or simply does this occur with some exhausts?

 

if you haven't already, i'd double check to make sure all nut & bolts are nice and tight. even if they are a just a bit lose now, they will be a lot loser later due to the vibration of the exhaust from daily driving. that's what i would do. also check to see if there is any metal against metal anywhere under there, that would also cause that annoying noise...

 

First, does your header bracket bolt onto anything? I'm thinking not, because mine is just the same way... I don't have a hatch, but after I did my swap, I got an EX catback, GSR test cat, and the stock B18 header... The only thing I had a problem with was that the test cat's holes didn't line up directly to the header, but with a little twisting of the exhaust piping, I got it to work... There is a little rumbling, but I think that's normal... Just check your bolts, everything should be fine...

 

DX Generation> Yeah you are absolutely correct. The holes don't line up quite correctly. I will try to twist the pipe today and see if I can get them to match up.