Exhaust Rattle

[Dinsy]

Hey Guys,

For about a week I have had a pretty nasty rattle while accelerating harder than about 20%, after quite a bit of searching and praying that it wasn't anything serious ..... I believe I have found out where it is coming from. As per attached pictures (Yes I know they are terrible quality, but the conditions didn't lend much assistance in that regard)

 

I am hoping to avoid doing a dodgy and just affixing some form of padding between the exhaust and the arch to stop them making contact, however at the moment nothing else is really coming to mind until I can get it on a lift or set of ramps. From what I can see (again not the best conditions to have a good look around), the only points where the exhaust is actually attached to the car is by the exhaust manifold and the two heavy-duty leather straps either side of the muffler.

Should there be another attachment near the middle of the exhaust that a bolt may have sheared or have wriggled out from?

 

Any advise or suggestions would be greatly appreciated

 

Cheers

Dinsy

[Zedman240®]

One thing to try is to shake the exhaust by hand and see if you can re-create the noise while the engine is off. You could be mistaken by engine detonation rather than a exhaust rattle?

[Dinsy]

Zedman,

I gave this a go last night while I was under the car taking the photos just to make sure that it really was causing the rattle. While I had to put a little effort into shaking it, it was by no means enough to make me worried that I'd knock the car off the jack and break my ribs. From the second photo, you can see the dark patch on the exhaust where it has been hitting the arch and rubbing off accumulated road scum.

Yesterday afternoon I asked one of the guys I work with to take it for a drive and give me his opinion (although not overly familiar with Z's, he is pretty experienced with troubleshooting car issues), and agreed that it was most likely the exhaust rattling somewhere (sounds like hollow steel pipe being with with steel / ball bearing hitting a tin roof, and no noticeable loss of power while rattling).

 

I was initially worried that it might might have been the engine knocking, but as the car hasn't lost any of it's power, and the noise seems to be coming from the center console, I am really hoping that it is just the exhaust.

[hunterzed]

Check your engine mounts. Have you noticed that power has dropped or is that still the same?

[Dinsy]

Hunterzed,

The engine mounts all seem to be fine, nothing loose or broken.

 

From what I can tell there has been no noticeable loss in power, that said I haven't pushed it very hard through 2nd and 3rd gears as the rattle gets louder and faster with increasing revs, making me feel very nervous  (rattle stops if throttle is backed off to maintain speed / revs rather than accelerating), 4th isn't too bad ... and a couple of nights ago (in the name of science and problem solving) I was able to find a nice piece of wide, straight and deserted highway to let it fly in 5th with no noticeable loss in power or rattle.

[hunterzed]

Well if its a rev related problem instead of a speed related problem then there is something not right with the drive line forward of the gearbox. If it was just a loose exhaust it would happen over bumps and other times at random. Check your harmonic balancer and your gearbox mounts as well. Also check anything that is driven by belts to see if they are out of whack. Where is the noise coming from? Is it up near the gearbox or down near the back of the car. Check all your exhaust mounts as well as shaking it from both the front (at the bottom of the down pipe) and the rear of the exhaust to try to replicate the noise. If all this comes up with nothing then you may need to just make some adjustments on the exhaust until you find the sweet spot again.