PG manifold heat issues

[Haltech]

How much was that Sterling coating? $150?

[Anklh]

The Extreme Sterlling was somewhere in the low $200's.

[Crossbow]

After the turbo it does not matter. The separate issue is avoiding the cooking of everything else nearby.

Is this because effective exhaust scavenging can't occur because the turbo is sitting in the exhaust stream? (Unlike an NA engine, which would have headers trying to match up exhaust pulses for effective overlap and scavenging )

[Speedy3]

Originally Posted by Crossbow Though coating will have diminishing returns the further you go down the exhaust stream.... Anytime you can keep the exhaust energy in the piping, and not dissipating out into the surrounding air, is a good thing. Remember, its not just keeping the heat away from the rest of your car, it's maintaining that heat and velocity in the piping itself. I'm crazy about heat though. I'm the guy who will have an upgraded radiator, coat his manifold, turbo, and DP, and probably wrap the IC piping. Hmm that reminds me...I wonder if mazdamotorsports has a radiator for the ms3.

If you have a non-catted DP, the coating it inside and out WILL improve exhaust pressure through thhe turbo. Otherwise, once the exhaust exits the turbo, it's gonna hit a thermal wall in the DP and lose pressure, causing upstream losses. Since I'm going with the catted CP-e DP, i'm gonna just have the exterior of the DP coated to reduce some heat loss through radiation.

[redrocketz]

Originally Posted by Speedy3 If you have a non-catted DP, the coating it inside and out WILL improve exhaust pressure through thhe turbo. Otherwise, once the exhaust exits the turbo, it's gonna hit a thermal wall in the DP and lose pressure, causing upstream losses. Since I'm going with the catted CP-e DP, i'm gonna just have the exterior of the DP coated to reduce some heat loss through radiation.

I wouldn't recommend getting the Catted part coated even on the outside you don't want it ot overheat and melt. I would also ask CP-e if it is OK to do that in terms of warranty.

[enganear]

Originally Posted by Crossbow Is this because effective exhaust scavenging can't occur because the turbo is sitting in the exhaust stream? (Unlike an NA engine, which would have headers trying to match up exhaust pulses for effective overlap and scavenging )

You are complicating a discussion of heat with a discussion of pulses. Heat management has nothing to do with scavenging.

-Heat is energy.
-The turbocharger works by recovering energy from the exhaust and mechanically transferring it to the intake.
-The exhaust downstream of the turbo is much cooler than the exhaust ahead of the turbo because of the energy removed by the turbo.
-Insulating the exhaust downstream will have no positive effect of energy removed from the exhaust by the turbo. Cooler exhaust is more dense and can theoretically result in reduced backpressure, although I doubt seriously you could actually measure the difference in backpressure caused by insulating the pipe after the turbo.

-enganear

[redrocketz]

yeah I'm with Enganear. The cost far outways any benefit of coating anything after the turbo

[Crossbow]

Thanks for the info! Makes perfect sense.

[SgtP]

good info here

[cld12pk2go]

I went down the wrapped path, and it works very well.

I might wrap the first 12-18'' of my downpipe as well just to keep things cooler in the engine bay (if my CP-E DP ever arrives).