Jet Hot or SSi's

[rsrguy]

So, I've been told that when Jet Hot, coats headers that they actually coat the inside as well. The reason being that they exit heat more efficiently.
This is the question, Is the ceramic coating going to exhaust more heat than stainless? Will I pick up an additional bennie to have the inside of the exchanger coated as well? you know the void that the heater air flows through.
Guy

[Rusty Heap]

Jet hot ROCKS as a coating...........no I wouldn't do it on Stainless SSI's, but on stock heat exchangers while off the vehicle, a 200% both thumbs up YES. you'll get zero rust, they can glow orange without the Jet Hot coming off, and Jet Hot also offers a second recoat if ever needed for free, or at least they used too...........

I'm totally sold on Jet Hot, used it in numerous applications. send it off to Jet hot and don't bother with local "hi-temp" powered coaters that "claim to be just as good".

Just my 3 cents worth of opinion.

[TimT]

The reason being that they exit heat more efficiently

Not sure your meaning in this statement..

Jet-Hot coating is an insulator... it keeps the exhaust heat in the pipe.. higher gas temps higher velocities etc.. If you mean exit heat out the pipe, rather than radiate the heat through the pipe walls... then yes

I don't think Jet-Hot can properly coat the exterior of the pipes, and the interior of the clam shell..

FWIW I had a set of headers that Jet-Hots coating failed on.... Probably it wasn't a coating failure as much a surface prep failure...

Jet-Hot re coated them no question asked...However the re coat is failing again...

[Gogar]

IMO:

If you're starting FRESH, just get some SSIs. If you already have a set of 'proper' early-style Heat Exchangers, then you bet, coat them.

The heat benefit, as mentioned, results from heat traveling out the back, instead of up and radiating back towards the engine. But I don't know if anyone has quantified the 'actual' temperature difference, which I bet is pretty insignificant.

I coated my OEM heat exchangers so they won't rust as fast. And they looked great for a week or two.

That two or three times I jacked the car up before they got dirty, I thought I was a HERO.

[RWebb]

ceramic on exhaust ports is used pretty often by manfs.

never seen one use a ceramic to coat the exhaust system per se - this should tell us something -- that the value of a ceramic decreases with the temperature gradient, that is with distance from the combustion chamber

some manfs. use Ti exhaust systems, so cost can't be an over-riding concern

how much does it cost? if cheap, then how can it hurt?

[911pcars]

If only for corrosion protection, uncoated SSIs should be fine.

However, as was mentioned, ceramic coating reduces high temperature from radiating back toward the engine. That's good, even on stainless steel exhaust surfaces.

As with any applied coating, the cleanliness of the base metal is important for long service life. In that regards, trying to apply ceramic coating to a used heat exchanger with unreachable interior surfaces is going to be futile effort in the long run. You might be more successful starting with a virgin set of heat exchangers.

Sherwood

[rsrguy]

All good info and very much appreciated, I'm just trying to figure out if it would be smarter to buy used regular x's in good shape and coat or used stainless x's and leave alone. The ONLY reason I'd choose to go the jet hot route would be if there was a legit perf gain, aka lower eng temps. So far it sounds like I better be looking for stainless, kindofa set it and forget it exhaust.
-Guy
more debate would be helpfull

[RWebb]

in that case, buy SSIs -- unless $$ are really tight

[rsrguy]

I think I'll be doing that. But used. Coating a set of x's would bring the cost way up.... to be about the same or more. Like I said the only reason to do it would be if there was a significant benefit

[911pcars]

Coating the factory HEs will also preserve the metal, at least from the outside. I have the same original HEs from '69. They were high-temp powder coated 10 years ago. So far, they haven't developed any holes although they're probably a touch lighter due to the "circle of life" cycle.

Sherwood