I'm considering getting exhaust manifolds ceramic coated. Then I learned that the coating will increase the emmisivity of the manifold vs uncoated cast iron. Moreover, the color doesn't matter cause it's emitting infrared. From a performance point of view if [coated]=[cooler exhaust] that's probably good. However, the manifold is pretty close to various hoses and the engine compartment temperature is already high. Anybody have any idea if the coated manifolds would materially raise it higher? I'm probably overthinking things, as usual, but comments still welcome.
And while we're at it, has anybody had custom, tuned headers made for a 6.9? Anything to be gained? Cheers,
Dave, from memory there have been some posts on mods on the 6.9, notably this dude appears to have had some nice gains:
https://www.youtube.com/watch?v=BxN4AQNzFYE
However on the header front, I think success is limited due to extremely tight clearances, plus you are dealing with massive heat soak due to the engine bay being so tight. Of course anything is possible with enough time and money, but I think it will still be marginal gain for the investment IMHO.
I used https://www.eastwood.com/eastwood-hi-temp-internal-exhaust-coating-w-nozzle.html on my 250S. I sprayed inside and outside. Has a nice silver color. I have no idea if it helps yet. I have had a real problem with vapor lock on that car and used the coating to try and help that situation.
On my 6.9 I sandblasted the exhaust and sprayed with clear VHT high temp paint. It turns them a nice grey color.
I had mine done on the 6.9 and the 280te im doing.
supposedly heat management is better, but im just tired of knowing they looked like crap.
I get them done a dark grey to look something like metal. I think originally they are light in colour but this would stain too easy (although the ceramic stuff supposedly cleans easier).
anyway, some pics on a thread from a couple of years ago
https://forum.w116.org/mechanicals/6-9-engine-rebuild-with-pics/75/
I did mine in the 450SE. Can't say heat transfer changed in any way, as it's always, quite literally, hot as hell under the hood anyway ;)
They did look great for a few thousand miles, then went murky brown around the hotspots, and eventually the coating started cracking albeit it's not flaking off. That's about 15k miles after.
Pretty sure it depends on who does it and the process. The ones on my 6.9 were done by the same mob as Nathan's and they're mint after quite a few thousand km.
Tim
I think there's definitely gains to be found with custom headers since the standard ones are very compromised with small collectors. Use the later tri ys as a basis for the design.
I would also add twin snorkels & cold air intake to get the most benefit.
Ceramic is the best option currently available ATM so just go with that but make sure they're thoroughly cleaned before coating.
I'd seriously consider bonnet vents to get rid of all that trapped heat....
Louvres on, or behind the fenders, like Buicks ;) Maybe with high power fans behind them.