nick73 is correct.
The heat energy in the exhaust is what drives the turbo. The gas is hot and compressed, there is only one way it can expand- thru the turbo. The hotter the better. After the turbo however, do not wrap or coat. If the pipe after the turbo is kept hot, the exhaust gases will not cool and contract and will reduce flow thru the turbo.

I am told that some race cars do have heat wrapped exhaust pipes, the reason is to keep heat away from fuel tanks.

Interesting point about not wrapping dumps...

I agree that heat is energy and that you want to maximise the heat/energy hitting the turbo but as gasses cool they slow in velocity and so keeping the heat in keeps it moving out faster.

I don't think it is as critical post turbo as most people have 2 inch up pipes and 3 inch dumps.

I've got a blanket on my dump (Perrin), but purely for heat soak prevention with a TMIC. Turbo blanket as well for the same reasons, but also assists with keeping the turbo hot for spool.

A 2" Subaru Up Pipe is larger than stock typically for larger aftermarket headers and turbos. The stock size is 1.75".

Caution should be had here as 2" will reduce the velocity in some scenarios. The Grimmspeed up-pipe goes from 2" to 1.75 to increase velocity more as gases head towards the turbo. I like this idea.

I am however still tossing up between the Perrin 1.75" up-pipe wrapped, or the Grimmspeed one coated (from factory) and wrapped, as a replacement for the OEM MY01 up-pipe which is catted. I've seen a thread where with the grimspeed one, as it has a flex join, this can be seen as a weakness and crack, where the Perrin is solid all the way.

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[SIGPIC][/SIGPIC]
Should have bought an STI

My mate had his headers for his 355 stroker ceramic coated and was warned that the coating would perish if he got to much heat into them from doing burnouts to long. For this reason im swaying towards heat wrap for my headers in the future

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The one perkent...

For when you do burnouts in your wrx?

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Air is for pussies.

I like your thinking Tony.

I was giving you some context as to why he was told that. As it wouldn't be hard to get similar heat into the headers doing afew laps at full noise.

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The one perkent...