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Thread: Heat wrapping vs Ceramic Coating a header

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Posts: 21-26 of 26
2009-04-13 23:28:17
Ive Got About 25 Feet Of Coolit Thermal Tech 2 Inch Gray Header Wrap If Anyone Wants Ittt....25 Shipped
2009-04-14 19:48:57
I'm sure the header wrap works a little bit better. But the ceramic coating just looks so much better, prevents rust too.

There is a coating place around here that sells a coating that is good for 1600*F. One of my friends has a manifold coated with it. A GT42r and after going for a spin he popped the hood and touched the manifold.

Normally you would come back with no fingerprint and in pain, but he clean wiped his finger on the manifold and didn't get burned.
2009-04-14 20:09:26
Originally Posted by Coheed
Ben, don't take this the wrong way, but this is a little off base.
How so?

Originally Posted by Coheed
Sure, you get more corrected flow with cooler air.
So what's the problem?

Originally Posted by Coheed
Cooler air is more dense. But the mach speed of the air is increased with increases in temperature. Pressure has no effect on Mach.
Sure, but we only care about mass flow, am I wrong? How do you get the most air through a pipe the fastest? With cooler air.

Originally Posted by Coheed
in order to increase speed beyond [mach 1], you must increase temperature. Increased temps cause excitation of the air molecules, which will cause them to move more quickly.
Yah the molecules move more quickly, and the gas gains speed and you get more flow volume, but you get less mass flow. Which is what we're really interested in.

Originally Posted by Coheed
This is why the turbo will spool faster with a manifold that is coated. But you are right about scavenging. This is a two-fold reaction. You increase scavenging, and gas speed by keeping temperatures higher.
I have to concede on this point. I thought about it at dinner last night (Mexican). Even though you have less mass flow through the turbine with hotter air, you do have faster moving air, and thus more momentum to the molecules. Even though you have less molecules hitting the turbine blade they are going to hit it faster, and speed works on momentum as an exponent unlike mass which works as a coefficient.

Originally Posted by Coheed
So while you can increase flow with a temp drop, you can increase velocity with a temp increase.
Yah, and that's why a turbo will spool quicker with hotter air. I get it. I was a bit off there.

Still, after the turbo, or after the merge collectors in a N/A header, you want the exhaust to cool down quickly for best flow, not stay warm. Agreed?
2009-04-14 20:25:46
Agreed! Good work Ben.
2009-04-14 20:28:37
What you could do, is keep the gas as hot as possible without damaging anything, but enlarge the pipes as to increase your mass flow. Win-win. Though going with a larger pipe will slow the gas speed slightly.
2009-04-14 20:39:22
double wrap it..

no glove.. no love..
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