smccurry

After having my Mugen header installed at a local tuner shop, there has been a clunking noise coming from under the car when going over bumps or making a turn at any speed over 5 MPH. I did take it back to the shop immediately after noticing the noise, and they put my car back on the lift. The mechanic said that the header shifted the angle of the catalytic converter ever-so-slightly and as a result brought it closer to the underbody of the car. He unloosened the bolts and pulled on the whole assembly away from the underbody and re-tightened it. The noise went away for about 2 days, and now it's back again. I don't have the time or the tools to lift my car every 2 days to re-shift the cat away from the body. Has anyone had the same problem? Or have any suggestions? The installer says it's not their part, so they're not liable for the fitment of it. I doubt that Mugen's workmanship is in question, but I'm not sure what to do. Thanks in advance for any help.

Austin_S2000

I personally installed the Mugen header and have had no problems. I was really impressed on the quality of the header along with the fit.

Since this the first time I have read anything like this, you may have a quality problem with the header. There are three places the header actually bolts to. The first the head, the second near the bottom of the transmission and then finally the cat. Did they use the transmission mounting point to secure the header?

--Jose

smccurry

Yes. I visually inspected the installation when it was done and could see that it was bolted to the transmission. Well, I didn't know it was the transmission that it was bolted to, but it was bolted to another point besides the head and the cat.

biker1

The bracket refered to can be fitted two ways if they have got it wrong way round (which is easy to do) it does alter the angle that the cat attaches, thus bringing the cat near to the underbody heat shield.

smccurry

Thanks! I will take it back to the shop and mention this.

smccurry

**UPDATE**

I couldn't find any other way to mount the header to the transmission case, so that wasn't the problem.

With Rick's help (rstark), we managed to find the source of the problem (or so we think). The resonating canister on my J's N1 exhaust was rattling against a crossmember of the chassis. We remedied this by bending one of the exhaust hangers downward and away from the metal beam and this partially cured it. It now only makes the clunking noise during more aggressive cornering, so I'll have to make a few more tweaks (hopefully) to make the sound go away completely.

So the moral of the story is...
Be sure to check body clearances for the entire length of the exhaust system when changing out exhausts or headers.

XTC at 9K

Dam!! it took a while to figure that one out it must have been killin'ya

smccurry

[QUOTE]Originally posted by XTC at 9K
[B]

Dam!! it took a while to figure that one out

rstark

smccurry, I just bought a new vise grip, so any time you're ready! BTW, you still have my allen wrenches right?

smccurry

[QUOTE]Originally posted by rstark
[B]smccurry, I just bought a new vise grip, so any time you're ready!