In the Hot Seat

[grady]

How close can the center (under-seat) mufflers (silencers) be to the underside of the body? Mine got pushed up a bit and burned/singed the fiberglass and carpet. I was able to twist it down slightly but both sides are still very close - almost touching. Is the any insulated material that should go between them? Thanks Grady

[adam quantrill]

If I am right, on the 280i the exhaust goes high up in the transmission tunnel?

What upgrades have you added? I reckon any more gas flowing though this will cook the fiberglass.

You could either try the underslung exhaust, 350i style, or perhaps installing a heat shield (thin aly sheet might do the trick).

[grady]

Actually this is all a stock set-up... The 2 exhausts run down the transmission tunnel but on both sides, the fiberglass has a raised section which the seat sits upon. Snug up under the seats - filling the raised space - is a "U" muffler (the gas goes in and out of the same end). In addition to 4 90 degree bends, it's clearly a compromise between dangling mufflers and burned fiberglass.

From time to time, I've smelled the fiberglass get "hot" but the other day it got hot enough to smoke a bit and that's when I discovered the fiberglass was crumbing and the carpet scorched (under the seat).

There are various insulating pads... can anyone recommend one that can be put in contact with both the heat source AND what you are trying to protect?

[leorest]

grady said:

...There are various insulating pads... can anyone recommend one that can be put in contact with both the heat source AND what you are trying to protect?

I would think the best thermal barrier would be provided by an air gap and a reflective heat shield. I know space is tight but anything contacting both surfaces is only going to conduct heat and noise too! If you can duct some airflow through the gap it will help enormously and also if you replace the silencer with a stainless one it will cut down heat. If you've got unlimited funds then ceramic coating to the silencer will switch the problem off. Exhaust wrap is not recommended for a multitude of reasons.
HTH

[adam quantrill]

leorest said:

Exhaust wrap is not recommended for a multitude of reasons.

Yeah - on mild steel, it accelerates the rot. However, combined with your other suggestion, a stainless pipe, it might do the trick. The stainless should survive the wrap treatment. Worth a try.

[shpub]

Try NimbusG3. Expensive but very very good.