[classicauto]

A few people run cermet housings. I know charlie (busted7) runs a pair in his engine. 20lb spring, big turbo, 500whp on pump. There's upsides and downsides but I think in the case of the housing the gains or losses will be minimal.

The argument can go two ways:

1) By doing the coating, you're keeping more heat in the chamber, losing less energy to being absorbed by the housing, make more power.

2) By doing the coating you're keeping more heat in the chamber, raising the chances of preignition.

The friction factor I don't even know. Personally I think ceramic seals (which have a proven lower friction coeficient then OEM steelies) in OEM housings is the best - mathematically - for reducing friction with regards to housing vs. apex seal. I can't find any info saying that JHB cermet *IS* more slippery then the factory stuff, plus who knows if it holds oil as well, etc etc.

Personally, with the problems I've seen first hand with Cermet housings (older versions, but nonethelss) I wouldn't want to risk it. Buy a pair of OEM's and you know what you have. Its not like getting them coated makes it any cheaper - a pair of useable housing + coating (JHB) is about equal to a pair of new, plastic bagged, housings from the mother ship.