I have the Vishnu Signature catback that I just installed last week (turbo back to come) and I've noticed the last two times I've pulled into work, slow speed right turn, that something is clanking/rattling under the car. It never happened before the exhaust, so I assumed that's what it was. So, I got home last night and crawled under the car, and the v-clamp was turned funny and was pretty close to the driveshaft, so I shook the exhaust back and forth and sure enough, it would hit. I loosened it and turned it away and clamped it back down, gave it another shake, and had much better clearance.

Today, it happened again. Does this happen to anyone else? Is there anything I can do to help prevent it?

 

it's not the design of the exhaust that's causing the problem, it's the brackets and clamps. I have the HKS exhaust and I experience the same problem. You might want to get some new exhaust hangers, kartboy ones, that might help.

nebo

 

What do Kartboy hangers do differently?

EDIT: Nevermind, I went to the site and read about it. Do they make a big difference? For $40, might be worth checking out.

 

I have the exact same problem. The exhaust is just too tight back by the rear drive shaft universal joint. When it heats or cools down, the exaust expands and contracts and changes it's shape and if it's already close to something else, it mays start hitting it.

I drove through a puddle the other day and it was enough to cool the exhaust to the point that it started banging on the drive shaft. I thought I'd ripped the oil pan off!!! Very disconcerting.

This is my 3rd exhaust from Vishnu, the first 2 where a joke, this one's pretty good, but not perfect (they said they had recently changed fabricators because of quality issues - this is about a year ago). I just use a piece or coat hanger to keep it pulled away from the drive shaft. Sounds very shade tree mechanic, but it works.

I even took it to AMS in Chicago to look at but they couldn't do anything without re-bending it.

 

I crawled back under there today after work and it's not the driveshaft or the v-clamp...it's just the exhaust behind the v-clamp hitting a bolt that holds the rear diff together? I think it was the rear diff, it was about a half inch from my face. I adjusted the rear hangers to pull the rear of the exhaust as far to the passenger side as possible, away from the bolt.

I did order the Kartboy hangers today, just to give it a little extra stiffness.

 

lemme know how that works out, i think i might have been experiencing the same problem

 

I have a megan exhaust and have the hitting issue as well. I went with the kartboy hangers and it didn't make much of a difference. My motor moves enough to cause it to hit when under load. I either need to get mounts or I need a dampner.

 

the heat sheild arround where the cat used to be sometimes hits teh exhaust... you might want to nail that down it worked for a lot of people.

 

Actually this happens to a lot of aftermarket exhausts. It sounds HORRIBLE...like something is really f'd up...but nothing is actually hitting the exhaust. Has something to do with odd properties of metal tubing and rapid cooling.

I've got a Bushur exhaust and it seems to bump against everything. I took a metal tie and tightened it down around the circumference of the hangers....same effect as the kartboy (less movement), but my downpipe still bangs on the transfer case.

 

My Vishnu Signature Series CAT back did the exact same thing, but I fixed it. I loosened the rear band clamp first (just enough to allow the two pipes to rotate freely). Then I removed the exhaust hangers (for the muffler) and rotated the muffler UP as far as it would go (the muffler should rotate freely where the band clamp connnects to the CAT back pipe). I then tightened the band clamp back up (while the muffler is stuffed up as far as it will go). Then pull the muffler down far enough to reattach the hangers. The area of the exhaust where the band clamp is will now be an inch or more away from the drive-shaft. This method worked great and has held that position for over a year now. Mine is actually almost two inches away from the drive-shaft now. Try it and you will see...

 

Great suggestion...I can see conceptually how that would work.

I got my Kartboy hangers today, so I'll do your trick in addition to the new stiffer hangers and see how it works out.

Thanks to everyone for the input!

 

I had to do the exact thing, only it was the heat shield closer to the firewall, right where the passenger foot well starts. It was hitting the dp/cat. flange assembly, prior to the cat itself.

 

just break out the damn hammer

 

My dp rattles under the passenger floor board also (rather embarassing when your getting a dyno tune). I also do have the kart boy bushings which are a slight help but they are not, "the fix". My dp is the new improved version with no flex section or transfer case hanger (that's what I thought I ordered, but it's not what I got). The Xfer hanger may have helped with the rattle as advertised on the previous version.

I have not had the time to look into a fix yet. It's on my list of stuff to do but any feed back would be appreciated.

 

When I first installed my Helix version 2 downpipe, it was hitting the cross member just a little bit. It would sometimes hit harder under certain acceleration conditions. I fixed this issue by doing two things: I purchased the KartBoy hangers, and I slightly tweeked the hangers behind the cross member. The hangers on the car in front of the CAT are fairly easy to move in any direction using a "cheater pipe" slipped over them. I moved both of them down a little bit and one of them to the side a little bit. There is a fine line between it hitting the cross member or it hitting the cross bars. I was able to get mine right in the middle and does not hit under accel or decel. It is also possible to tweek the two hanger mounts on the downpipe itself, near the CAT. If you are willing to just spend a little time bending these hangers, you can get your exhaust fitting great. I had to tweek mine, and had to do the Vishnu Signature series "fix" I described above. My exhaust is now dead center and does not hit anywhere...