Exhaust Pipe Clearance?
Exhaust Pipe Clearance?
(OP)
Can anyone tell me if there is a minimum clearance requirement between an exhaust pipe and a heat shield, and between the heat shield and structure or a component, specifically a gas tank? I have a newly installed performance exhaust system that the heat shield is riding on the exhaust pipe and there is very little clearance (maybe .16”) between the gas tank and the heat shield. Also, with the reduced clearance between the gas tank and heat shield, should there be a concern for a hot spot on the tank? THANKS!





RE: Exhaust Pipe Clearance?
Some heat shields are happy to be wrapped closely around the puipe, others use the air gap.
Is the tank plastic or metal? is the heatshield insulating or reflective? Do you care if the pipe clonks the tank?
I don't know of a regulatory limit , but I can imagine scrutineers or inspection mechanics raising an eyebrow.
Cheers
Greg Locock
RE: Exhaust Pipe Clearance?
RE: Exhaust Pipe Clearance?
It probably won't melt your tank, what it will do is heat the fuel more, which is very bad for evaporative emissions.
Cheers
Greg Locock
RE: Exhaust Pipe Clearance?
very low, where it is "always" cooled by the liquid, might be a tiny bit safer- higher up, no cooling of the plastic...
Are those tanks thermoplastic? I'd imagine not, but what temp are they typically rated for?
Crewchief said 0.16 inch - that's about 4mm !!!!!
I'd vote for another 1/2 inch or so.
do you carry a REALLY BIG fire extinguisher?
Jay
RE: Exhaust Pipe Clearance?
Cheers
Greg Locock
RE: Exhaust Pipe Clearance?
RE: Exhaust Pipe Clearance?
RE: Exhaust Pipe Clearance?
RE: Exhaust Pipe Clearance?
Cheers
Greg Locock
RE: Exhaust Pipe Clearance?
If this is still not to your liking, do as Jay reccommends. Better yet, install a BIG AFFF fire system. I have had one of these plastic tanks on a truck catch fire from a broken exhaust---IT AIN'T MUCH FUN, BOYS!
Rod
RE: Exhaust Pipe Clearance?
Greg- Another interesting combo i've seen if the exhaust manifold heat shields on the mitsubishi 4g63 turbo engine. They have two layers of stamped steel with a layer of a slightly fibrous gypsum board material i sandwiched in between, and riveted together. The stuff in the middle tends to crumble when you cut the shield to make room for bigger turbos and external wastegates :) Any idea what it is?
RE: Exhaust Pipe Clearance?
Rod- sounds like you've melted, burned, exploded, or otherwise destroyed a sample of every type of mechanical device known to man... how is it that you've still got all your limbs and a pulse? I push my luck pretty far at times, but I don't think it'd carry me nearly as far as yours seems to have taken you!
RE: Exhaust Pipe Clearance?
Nick
RE: Exhaust Pipe Clearance?
Jay
RE: Exhaust Pipe Clearance?
Nick--- I have been carrying fire extinguishers in my cars since the first fire (my brother-in-law's Ford/Olds, c.1959). If you attend car shows you will find that ALL are required to have them. My Mini is an extreme case with the AFFF system but, it will eventually be raced in vintage races.
As to the plastic fuel tank fire---I did not even know it was on fire until someone flagged me down on the Pomona Freeway!!! The spare tire was also on fire and no one could get close enough to me to tell me. I was on my way home and in the "zone". The 20 lb. extinguisher I had in the tool box saved the day.
Rod