Heat Shield: Blanket or Stainless Steel cover?
#27
Looking into buying a PTP blanket. How did yours hold up?
#28
Racing Rotary Since 1983
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From: Florence, Alabama
heat shielding is important from a couple of aspects:
if the manifold positions the turbine housing near one or more of your lower intake manifold runners you do want a heat barrier between the two.
heat shielding around the turbine housing can reduce the overall engine compartment heat which is generally around 165 F. the housing shielding can also cause discoloration in the underside of your hood paint... you have removed the rug on the backside of the hood right?
as mentioned in the thread, there are a number of ways to deal w the heat.
my manifold purposely positions my turbine housing very close to the exhaust ports and therefore the LIM.
a cherry red housing near aluminum (one of the most heat receptive materials on the planet) is a recipe for disaster. front rotor lean, rear rotor rich. your O2 sensor reads the average and you will tune to a point where the front rotor is just too lean.
Cam Worth was dynoing a customer car that lacked a barrier. he grabbed a sheet of steel and inserted it between the turbo and the LIM and the next run the AFR richened almost a point!
a heat BARRIER is needed and MICA is the answer.
MICA as in ZERO heat penetration on the other side of an 1/8th inch sheet. buy a square from McMaster Carr for around $60. you can saw it, drill it etc. if you look at a chemical properties list you will find MICA next to the absolute bottom as to heat transfer.
i heated a sheet of MICA for 2 minutes w a propane torch (1300 F) and was able to touch the other side.
as far as a turbine cover... i would be concerned if all the heat was captured inside.
the retained heat has to go somewhere and a bunch of it goes to the oil/bearings of the turbo. oil degrades above 400+ F.
i just go w a stainless steel shield. i realize my under hood temps are higher than if i ran a blanket but i would rather give my turbo bearings a break.
howard
if the manifold positions the turbine housing near one or more of your lower intake manifold runners you do want a heat barrier between the two.
heat shielding around the turbine housing can reduce the overall engine compartment heat which is generally around 165 F. the housing shielding can also cause discoloration in the underside of your hood paint... you have removed the rug on the backside of the hood right?
as mentioned in the thread, there are a number of ways to deal w the heat.
my manifold purposely positions my turbine housing very close to the exhaust ports and therefore the LIM.
a cherry red housing near aluminum (one of the most heat receptive materials on the planet) is a recipe for disaster. front rotor lean, rear rotor rich. your O2 sensor reads the average and you will tune to a point where the front rotor is just too lean.
Cam Worth was dynoing a customer car that lacked a barrier. he grabbed a sheet of steel and inserted it between the turbo and the LIM and the next run the AFR richened almost a point!
a heat BARRIER is needed and MICA is the answer.
MICA as in ZERO heat penetration on the other side of an 1/8th inch sheet. buy a square from McMaster Carr for around $60. you can saw it, drill it etc. if you look at a chemical properties list you will find MICA next to the absolute bottom as to heat transfer.
i heated a sheet of MICA for 2 minutes w a propane torch (1300 F) and was able to touch the other side.
as far as a turbine cover... i would be concerned if all the heat was captured inside.
the retained heat has to go somewhere and a bunch of it goes to the oil/bearings of the turbo. oil degrades above 400+ F.
i just go w a stainless steel shield. i realize my under hood temps are higher than if i ran a blanket but i would rather give my turbo bearings a break.
howard
Last edited by Howard Coleman; 05-28-13 at 01:44 PM.
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