Updated 5/30/2004

Extreme Heat Coatings


Imagine this right below your intake manifold! That's what it is like in our 2.2 & 2.5 8-valve Chrysler when under a heavy load from a real heavy foot.


I can't lie and tell you that from experience that "Ceramic Coating" the exhaust will make a huge change in my Intake Manifold temps, but I soon will be able to state factual temperatures of air through the manifold once the new turbo is finally in place and the new motor built and compare them with previous data log.

This has by far not been the "cheapest" thing I have decided to try. It has in fact been an availible option for me so I had it done. This polymer called "Cobalt", which is only .0015"-.002" thick, can withstand up to 2400 degrees Farenheit, and still be flexible enough to expand with the metal so that it doesn't crack or flake off.
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Above is a before & after shot of the same turbo.


I was told by a very respectable and helping turbo vendor NOT to coat the inside of the exhaust manifold or turbine housing for the fact that the coating might flake off and damage the turbine wheel when it's spinning at high speeds, but I could not accept that advice. I have thought much about this and really could not see the point in spending the money on these coatings when it would seem like the inside coating is acctually the biggest insulating factor of reducing temperature. I asked Carl Benton at Polymer Dynamics (PolyDyn) if there were any problems with people calling and saying that their Cobalt coating is flaking off and/or tearing up turbochargers, he said that as long as he has been doing this particular coating that no person has had this problem. I believe the coating Carl said will flake under high EGT circumstances is a Bronze colored material which is much thicker when I saw it personally and must be lapped down alot for more clearance so it will not hit the turbine wheel.
(Plus, if something happened and I would have to rebuild the turbo, I could then change to the full T04E compressor housing that the large 50 trim wheel should be in).
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The compressor housing has 2 coatings, a type of silver coating inside said to help heat and promote air flow, it is about .0015" thick and has no clearance issues with the compressor wheel. I did in fact have to remove the small amount around the inside edge where it slips over the inside backing plate lip. THIS STUFF IS TOUGH TO REMOVE!
The darker layer is the same "Cobalt" coating as on exhaust side to keep the ambient temperatures out. There is one problem I have thought about on coating the compressor, is the temperature worse on the outside of the compressor, or the inside where it is almost in direct contact with heat transference from the exhaust side.




Pic of the coating inside.
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Turbine housing before & after.

The only thing I did to the coating around where the turbine wheel would be was just rubbing it lightly to make it smooth with some 800 grit paper. The same went for the opposite side where the swingvalve attaches. Just to satisfy my anal ways.
The Cobalt material is heated only about 450 degrees after it is applied, and is not completely cured until it has seen the high exhaust temperature, so, when it is rubbed with sand paper, it doesn't take much at all to remove or smooth the material.
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Updated 6-03-04




Pistons, main bearings, and rod bearings came back this week. "PolyDyn is definately pretty fast at getting this stuff back to you." As the picture shows above, they were also courteous enough to shrink-wrap and seal the bearings when they were done.





These look too nice to even install.



The top coating is a ceramic called "HS GOLD" which is .001" in thickness.




The skirts are coated with the same as the bearings called "DL". Not shure, but I think there is a second coating under the DL. The total thickness of the skirts ended up being .001" total (.0005" thick each side).




As mentioned above, the bearings are coated with PolyDyn's "DL" coating. Even though it looks dull and rough, it feels more slick than the bearings original finish and is still yet to be polished out after removing little material to gain desired clearance .



Any questions about these coatings, tell them you saw it on TURBOFREAK.COM!, please E-mailPoyDyn.

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