Question about EGTs & Exhaust

[turbo4agte]

I know on a high boost turbo engine, its possible to reach EGTs of up to 1700° F depending on the tuning. My question is, if the EGT is 1700° F what would be the median temperature of the exhaust manifold itself?

Reason I ask is because I want to ceramic coat my exhaust manifold. A co-worker of mine can powder coat it for me, and has been able to find powder than can withstand 1200° F. But Im wondering will the surface of the exhaust manifold itself would reach higher than that?

[Kyosho]

Ever seen an exhaust manifold on a turbo engine after some REALLY hard work?
You can often basically see through them the metal glows "white"... Same with the turbo...

[roadsailing]

My handy information tells me that at 1200 degrees F steel will be "blood red" and that when it is "orange" its is 1700 degrees F. I have seen plenty of orange turbo downpipes!

median temperature is irrelevant, unless you dont care it it only blisters off half of the exhaust pipe.

[The Real Roadrunner]

considering most turbo manifold can easily get to a "cherry red" heat i doubt a powder in the world could withstand these kinds of temps for long periods.

freeway driving your likely to see 400C but spirited driving id say the manifold could see upto and problably over 750C which is 1382* F near the collector and turbine housing.

really depends on a) tuning b) runner dia c) turbine A/R and a few other more minor things.

cheers
linden

[oldcorollas]

1200F is basically just glass (silica) softening temp.. ie poor quality exhaust wrap tape..

kyosho, "white" is really hot... we have furnaces that go up to and over 2000deg.... i'm not sure you would even call them "white hot"

and metal certainly doesn't become translucent when it is hot.. it remains opaque (afaik)

[af300e]

LOL @ white hot.

If the headers were in fact white hot they would certainly collapse under the weight of the turbo, downpipe etc.

White hot is around the melting point of steel, 1400-1600 deg centigrade.

Most of the EGT sensors I've found withstand up to 1100 deg C.