Exhaust hitting bottom of car...?

[90rps13]

Ever since I installed my catback exhaust it's been hitting the bottom of my car. It causes to vibrate right under my driver's seat at certain RPM's. I shaved one of the bolts that holds down the seat, so it's not hitting that anymore feels better, but it's still hitting the underbody down there. I've gotten new rubber hangers but still no change. Have any of you guys experieced this with aftermarket exhausts and anything you done to fix it...This is on a S13 body with SR.

Thanks

[Brian]

Are you sure it is not hitting anywhere else?

[chmercer]

go to an exhaust shop and have it cut and welded, or you could try the poly exhaust bushings on ebay or the nismo ones

apexi makes notoriously shitty exhausts, so, yeah...

[cgguy]

Nissan rubber hangers are like Jello. My catback used to bang on the rear sway bar like crazy....when I cornered really fast it sounded like someone taking a baseball bat to my underbody.

Get some poly-hangers or have an exhaust shop fabricate an additional hanger in the back to prevent it from moving around so much....just dont make it too stiff or the vibration will drive you nuts.

[kensreliableb18b]

it cant be that hard. u sure you checked over everything? like brian said, it might not be ur exhaust afterall.

[aznpoopy]

did you retain the exhaust bracket that connects to the transmission mount?

[90rps13]

Yes, it's still hitting right under my seat area, just the bottom of the car. I was just wondering if this is typical with bigger exhausts for the S13 and ways you guys fixed.

The tranny mount to the exhaust is actually the last thing I put back on this weekend, but still hitting.

So Poly hangers will stiffen it up, but will it make it too stiff where you will feel more vibration even if not hitting anything...?

It's already driving me nuts, seems like it's putting too much stress on my exhaust mani...specially since I have a cheapie Megan :)

[CKAMC]

hey if you can throw some pictures up and that would help out a lot to get a better idea on whats happening. This thread is starting to turn a bit technical but lets keep trying and hopefully pictures will help the rest of us tell you whats up.

[RightWheelDrive]

I had the same problem with my N1, shaving the bolt isn't enough. Cut atleast a cm off of it. After I did that, I never heard the vibration anymore. Good Luck.

[REDSH!FT]

Get a better exhaust that fits


Also, I use hose clamps around my hangers to pull them tighter

[sideview_180sx]

I doubt anyone had a bigger exhaust then me(except N1 dual owners) mine only rattled on the subframe, you might want to check to see if the heatshield is loose along with the grounding strap. if you have other issues, use work gear clamps to gain more clearance.

[jdm538]

aftermarket down pipe? cuz that could be your problem.

[OMGWTFBBQ]

mine used to hit the driveshaft, it finally just made a groove in one of the silencer things and stopped making noise

[ZX88]

my exhaust touches my differental and i cant tell if its vibrating or not did you remouve the toe hook cause it could be hitting that.

[ZX88]

jdm538 do you work for jdm garage and if so do u guys built custom exhausts just wondering.

[90rps13]

Nah, It's just hitting the under body. I have that Circuits Sports downpipe which has the O2 extension all in one piece. T28 s15 turbo too. Downpipe seems to fit really nice. Wouldn't be able to compare to stock fitment though cause I threw on a Megan dp with the SR swap. Which was a crappy fit BTW.

I'll try to get some pics in this weekend, but I might just end up banging in the bottom a little, I already cut off most of the bolt holding the drivers seat in, so it's not hitting that anymore for sure...or the diff (although very close).

Thanks for all the feedback...