Heat Shield material
Heat Shield material
(OP)
A friend of mine has decided carbon fibre would be a good material to craft a heat shield from. His theory being that if he can shield some of the heat coming from the block (it's a rotary engined vehicle), and avoid it getting to the intake manifold, it will improve intake temps.
I was under the impression carbon fibre did not make a very good heat shield. His thoughts were that he had a bike with a carbon muffler on it, and it could be touched and you would not burn yourself, while a stainless steel muffler would quite clearly burn you.
I know in top level motorsport gold leaf is the go, or even some sort of reflective cover on stainless steel. But for a street car? Would carbon work? Or even better, work well?
I was under the impression carbon fibre did not make a very good heat shield. His thoughts were that he had a bike with a carbon muffler on it, and it could be touched and you would not burn yourself, while a stainless steel muffler would quite clearly burn you.
I know in top level motorsport gold leaf is the go, or even some sort of reflective cover on stainless steel. But for a street car? Would carbon work? Or even better, work well?





RE: Heat Shield material
RE: Heat Shield material
I would use a thin 0.6 Stainless steel sheet that is highly polished.
Ken
RE: Heat Shield material
Radiation
Conduction
Convection
Shiny stops radiation only.
Low conductivity stops conduction.
Baffles and or containment of surrounding air stops convection.
Carbon is an excellent conductor of electricity, but a moderate to poor conductor of heat, and does not approach metal as a conductor of heat, but is still higher than glass. High is poor for this.
A major influence on the conductivity will also be the resin matrix. The resins used tend to have very low conductivity for heat.
Glass fibre will do a better job and is a lot cheaper.
Special heat insulation materials can be purchased from such places as welders supplies and industrial supplies.
It might be easier to insulate the intake air duct than the engine block.
Regards
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RE: Heat Shield material
also, aluminized fabric can reflect 95% at a temperature of 3000deg.F if i dun remember wrongly.
in your problem, you might consider aluminzed fibreglass fabric.
RE: Heat Shield material
I've used titanium in the past to some success in brake backing plates.
RE: Heat Shield material
There are a number of insulation materials that use Al sheet with ceramic paper between the sheets. ACL manufacture some, but there may be something more local for you?
RE: Heat Shield material
I wonder if a combination of steel and carbon pads may be developed that would act as a thermal shield?
RE: Heat Shield material
Fibreglass based insulation works just fine. Even better if one side is metallised with a very thin coating of shiny metal to improve reflection, improve structural integrity, and provide protection against saturation with liquids.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.