I had my HKS exhaust installed awhile ago at street image and the guys there said one of the pipes was too close to a bolt under my car and id have to live with a bit of rattling. The rattle isn't too bad but you can hear it thump a bit when driving in 1st gear. Do any of you guys with the HKS have this problem? Is there a way to fix it?

 

It seems to be a common problem, just need to make a small indentation in the exhaust where it hits that one bolt.

Gary

 

Same problem with mine, but worse. Mine was literally 1mm off the bolt, so it was a constant rub when the motor was on. The problem is with the angle on the flange welds. Without the last piece bolted to the mid pipe, the mid sat fine with a little (enough) clearance. With the flanges mated, the angle of the muffler piece flange pushed the pipes up to the bolt when tightened. I had the flange reseated/welded on the muffler piece and the problem is fixed, I thought that was better than heating and denting the pipe. (Thanks, AAM) Not everyone gets this problem, so I suspect it is just an inconsistency in HKS's manufacturing process. Sucks 'cause I did the install myself, and then spent the money I saved on welding.

In the OP's case, where the rattle is not constant, it might be easier to fashion a strap to a cross member to keep the pipe down.

 

My HKS exhaust rattles too. I was going to fix it but I'm real lazy.

 

Same problem but 1st, 2nd little 3rd when I push hard..

 

Mine fit perfectly and with no rattles.

 

you know, i had this problem with my first hks exhaust back in the day when they first came out. so i got rid of it due to this issue.
I now have the HKS on my car again, i purchased this one brand new recently, and it fits WAY better than my old one. I dont know if hks changed anything but the exhaust was on backorder for a very long time for a while there, so maybe they did a few very minor design changes, i dunno

 

There really is no quick fix. I ended up heating up the area making contact with a torch and flatened it a bit with a hammer.

One other problem I had was the muffer on the passenger side was just making contact with the fuel tube protector or diffuser, not really sure what the piece is called, but it had to be adjusted.

 

Sounds like a good idea.. It can easily be heated with a propane torch found at any hardware store.

 

how i got rid of my rattle, 06 hks

stand behind the car, get up under the car near the right exhaust tip , you will notice the clearance from the outer edge of the muffler to a box shaped metal part of your car is like 1mm, when the car is running this hits, you can easily bend the box shaped thing by hand by pushing on it, just push it with little force away from the pipe. this will get you about 2 inches of clearance and will never hit again.

the end.

this worked for me and it takes 3 mins to do.

 

got any picture of that metal box thing?

 

Mine fits perfect. I remember when i had it installed, my mechanic shook the exhaust real hard on the lift, nothing touched

 

i can get you a picture when i get home , didnt drive the z today because of rain.

 

OKay so this is not my car but i grabbed this picture off the internet to try and show you guys where it is hitting, i have outlined it in red.

there is a thin walled metal box, best way i can describe it. it hit the exhaust on HKS on the side shown cause its too close on some installs. mine was about 2mm from the box thing, this caused it to rattle. i pushed the box thing away from the muffler about 1/2 inch, this fixed the problem.

the box thing is like some kind of guard for something, the metal walls its made out of is thin so you can push it a little and bend it away some.

hope this helps, ill take a picture today after 6pm est and post it up of mine.

 

 

^ yours hit at a different place than others.
Mine hits at the place that everyone's talking about (the bolt). it's a POS design flaw of hks and mine hits as well. ONe turnershop tells me they take the bolt out and shave the tip for like a 1/4" clearance..

 

I did a ghetto fab and used a plumbing pipe restraint to create a gap.

but it snapped again.

 

thats because it is close to something and when there is vibration it is just slightly hitting

 

Does anyone have a picture showing the location of this bolt?

Could it be trimmed down with a cutting wheel?

 

Mine hit as well. Nothing a hammer didn't fix. Really...you have to make a small indention. on the pipe. Doesn't hurt performance.