I can't find the exact temperature stainless steel glows red at (assuming the manifold is SS) but its probably very hot and because of that you shouldn't turn the car off till the exhaust cools down a little bit. Thats why all those manifolds crack eventually.

 

i have the turbo timer set at 3min but after running it so hard i usually let it sit for like 10 and then i shut it off, so far i havent had any problems, ive never seen that in person, only in magazines, so just figured id ask how hot it was getting to cause the red glow!

 

wikipedia didn't have any information on glowing, if they don't...no one does!

 

Regardless of the material the manifold is made of it will be around 750 C before it starts to glow.
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Do you mean 1200 F ? I bet it would be liquid at 1200 C.

 

Oops, got my kelvins to Celsius formula backwards. I added when I should have subtracted.

That would be ~750 C. Somewhere around 1350 F.

Of course the manifold glows at much lower temperatures, but the human eye can't detect the wavelength.

Cast iron would indeed melt at 1200 C, as would some alloys of steel.

 

hmm, if your idling at 1300F+ then your setup has something wrong with it.

With my EGT gauge, I can only hit 1300+ when cruising at like 90mph on the freeway and as soon as I let off the gas it drops below 1100 in no time due to all the wind. Unless I did an emergency stop (from 90mph) and instantly opened my hood, I doubt I could ever see it red hot.