REFLECTOR: Exhaust coating

[Al Gietzen]

Subject: Re: REFLECTOR: Reflector Digest, Vol 33, Issue 61 Exhaust coating

 

The consensus seems to be that if you coat only one side, coat the inside.
Coating the outside and not the inside causes the exhaust pipes to become
very hot with no way to dissipate the heat.  It's my understanding that
cracks will show up with the ceramic coating without a problem.  Wrapping
the exhaust pipes is considered by many to be the worst of all worlds--it
keeps the pipes very hot and makes crack detection difficult.  However, mine
are neither ceramic coated nor wrapped, so I'm just passing along CW.

 
Chuck Jensen 

 

Chuck;

 

 I'll back you up on all counts.  I'll add that, IMHO; coating outside only
is primarily for appearance.  The coatings are very thin (.007 - .010",
IIRC), and therefore have very little insulating ability (conductive temp
drop).  And the emissivity (radiation transfer coefficient) of the outside
is generally not that high anyway (at least for SS pipes).  The bigger gain
by coating the inside is the reduction in the radiation heat transfer from
the hot gasses to the wall by lowering the emissivity.

 

FWIW, also just passing along CW (and I don't even know what CW is) :-)

 

Al

 

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