Ceramic coating, intake manifolds

[Ameer Antar]

I think you're both right. It all depends on the temp of the air in/outside the manifold and the temp of the manifold itself. The manifold can work as a heat sink to cool down the intake air a bit but not much since there is not that much surface area. This depends of course on the fact that the air outside of the IM is cooler than the charge air. The air around the IM is nowhere near the same temp all the way around, especially on the non-crossflow design heads such as on 10V motors. The exhaust manifold is very close to the IM and tends to warm this area. The top however can be much cooler, especially in a moving car. So the IM will probably absorb heat at the bottom and radiate some near the top.

I ended up coating my EM w/ 2000 F ceramic to reduce how much heat is radiated up to the IM. The ceramic is good at keeping the heat inside the manifold and pipes. I've heard lot's of bad stories about fiberglass wraps and such. I also coated the bottom of my IM w/ a bit of that 1200 F ceramic paint you can get in a spray can. This will further reduce the amount of heat absorbed from the hot exhaust compnents. I left the top of the manifold bare to radiate heat when it's possible. I believe Javad has also had his IM coated w/ ceramic, but then used a special coating all over which helps radiate heat from many materials. You might want to check out the site for info on that special coating.

-Ameer

---Original Message---
Date: Fri, 28 Nov 2003 00:54:48 -0800
From: "Richard Hoffman" <billzcat1 at hotmail.com>
Subject: Ceramic coating, intake manifolds
To: <quattro at audifans.com>
Message-ID: <BAY2-DAV9S7YN38CfCs0000a4e4 at hotmail.com>
Content-Type: text/plain;	charset="iso-8859-1"

Hello All!
I don't have a terribly important question...but I was always under the
impression that ceramic coating an intake manifold helped lower intake air
temperatures by reflecting radiant heat in the engine bay.

Just recently (on an internet chat board, told you it wasn't that important)
I was told that the intake manifold is supposed to act as a heat sink and
absorb heat from the intake air.  This sounds totally backwards from
everything I've ever heard.  We're not talking some crazy intercooler/intake
manifold combo, or even a forced induction application.  Just a regular old
cross-flow 4v motor (use a 7A as an example).

Just looking for confirmation that the person who told me that is a dolt.
Feel free to doltify me, if appropriate!

Richard
90 CQ
70 100LS


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