Ceramic coating stainless steel tube headers

Hi All,

I used to be under the impression that it was a "Good Thing" to coat any and all exhaust manifolds. Now I'm not so sure.

If a stainless manifold is coated on the outside only, will it heat the metal to the point of significantly reducing the lifespan and strength of the material?

Are some stainless steel alloys more immune to this?

Is this overheating/weakening/cracking worry even valid?

I'm thinking of turbo applications, so temps might be higher than in NA setups.

Thoughts?

Stop using the word 'superheat', it means something very specific:

http://en.wikipedia.org/wiki/Superheating

But I can't answer your question. Sorry.

Fair enough.

Edited.

I can offer this: When folks wrap their headers, they rust faster, although that's typically attributed to the moisture and not the heat from my understanding.

I have destroyed a set of headers with wrap. To me, they looked burned on the edges and not rusted. I've never had a problem with ceramic coated ones though.

Always ceramic coat them inside and out. If the shop you're talking to doesn't do this, then move along.

I had the header for my 924 coated after it had melted two polyurethane front control arm bushings. After coating, it hasn't changed colors and the bushing no longer melts. Passenger is much more comfortable, though I should have done the pipe under the front floor board as well :/

Had the hot side, downpipe and cold side of the the turbo for my 951 done and so far no problems, though we'll see what happens this summer as the turbo sits directly under the intake manifold on a 951 and the large turbo actually rubber a bare spot on the bottom of the intake, so I coated the intake as well to reduce heat transfer.

With wrap you'll get that problem if there's too much overlap in any spot, the metal will get incredibly hot, turn brittle and break off from shock or exhaust pressure, creating a hole.

BTW, here's the header wrap a PO put on the turbo for my 951:

Here's what I found underneath that wrap (sorry for the blurry pic):

The wrap held the heat in and killed the oil seal and you can see the rust and marks from the wrap. Where the downpipe gasket failed, you can see where it burned as well.

Unless I've got a bunch of money and time to burn on new exhaust parts, I'll never use header wrap on anything. Heard too many horror stories and I've seen some damage first hand.

Well damn, I put header wrap on my new engine...but that's NA and I was careful to keep the overlap down. I have lots of friends who've had no problems for years with wrap on NA setups, even wrapping rusty headers.

@turboswede, what if you can't see the entire inside surface area, and can't guarantee good adhesion as a result? And you have a delicate turbine just downstream? This is why Swaintech say that in general they won't coat the inside of turbo manifolds.

That leaves coating the outside only. Will the stainless hold up, assuming the turbo is sufficiently braced?

I wouldn't coat only the outside of anything exhaust goes through for the same reason I wouldn't apply two layers of wrap.

Header wrap will kill headers quickly in RV/towing applications from the heat. The headers on my Camaro are wrapped, but they are crossover style and I needed to reduce radiated heat. They were used and not worth coating IMHO. They had been wrapped by the previous owner (wrap removed before I got them) and they were rusty. Seemed to be more rust on the inside than out.

As for stainless headers, I wouldn't coat them. Stainless holds heat in a bit better than steel so they don't radiate as much. At least the Stainless Works headers I had in my El Camino didn't. I even had a zip tie touching the collector (didn't see it for a while) and it never melted. If it wasn't for the extra costs, I would have SS headers on my cars.

@81cpcamaro, you wouldn't happen to have any vids or soundclips of your Camaro in action, would you?

180degree headers sound awesome!

Call these guys, as they are extremely knowledgable, and also honest as the day is long. Even if they can't help--- they'll give you the straight answer:

www.Swaintech.com 585-889-2786

I cooked the bejeezus out of a RacingBeat race header on my RX7. It started life as stainless and is now rusty as all get out. Never got coated or wrapped, just 1,900 degree exhaust temps.

My new header is getting coated with the stuff they use on turbine engines.

bradyzq wrote: @81cpcamaro, you wouldn't happen to have any vids or soundclips of your Camaro in action, would you? 180degree headers sound awesome!

I just realized I saw his car on Youtube while looking for flat-plane V8 sounds.

Joe Gearin wrote: Call these guys, as they are extremely knowledgable, and also honest as the day is long. Even if they can't help--- they'll give you the straight answer: www.Swaintech.com 585-889-2786

I think he already did

bradyzq wrote: @turboswede, what if you can't see the entire inside surface area, and can't guarantee good adhesion as a result? And you have a delicate turbine just downstream? This is why Swaintech say that in general they won't coat the inside of turbo manifolds.

Bradyz1, here is a short video of how my 81 Camaro sounds.
http://www.youtube.com/watch?v=wnck2ITynk0

Here is another video of the same headers on the previous owners Camaro, I bought the headers from him.
http://www.youtube.com/watch?v=o9Ye8fFH90w

Actually, I haven't communicated with them in ages. That bit I mentioned is on their website somewhere though.

My question is more material-specific, rather than process-specific.

I'll ask Swaintech. They sure are the go-to guys.

I sent them an email. (well, e-form actually)

I'll post back with the answer.

I had Swain coat my headers for the Targa Miata. I was getting enough heat that I actually melted the heatshielding on my trans tunnel. The car hasn't been run much yet, but they feel cooler to the touch.

The one I burned through was a naturally aspirated street car, BTW. I paid close attention to how I wrapped it, but it was my first time doing it. Just like most people who do it for the first time

I have been applying ceramic coatings since 1998. Coating only the outside has not created any issues that I have seen or heard of. The coatings reduce the radiated heat. The surface temp will still be quite high, depending on your application. I am still running the coated stainless header on my RX7 that sees egt's of 1650 as a norm. No cracking or other problems after 5 full racing seasons.

@Don49, Encouraging data point! What grade of stainless is your header made from?

tuna55 wrote:

Joe Gearin wrote: Call these guys, as they are extremely knowledgable, and also honest as the day is long. Even if they can't help--- they'll give you the straight answer: www.Swaintech.com 585-889-2786

I think he already did

bradyzq wrote: @turboswede, what if you can't see the entire inside surface area, and can't guarantee good adhesion as a result? And you have a delicate turbine just downstream? This is why Swaintech say that in general they won't coat the inside of turbo manifolds.

If they can't reach it, then they won't coat it. Since the place I go to is local, I stop by with the parts and talk to the coater directly and he tells me what he can and can't do. Simple as that. Granted, cast iron is different than thin stainless, but they had no trouble with the long tube 4-into-2-into-1 header either. http://www.finishlinecoatings.com/

If you are thinking of having it done locally, have a look at some samples. My local coater shot my original header with ceramic. It had the quality and longevity of high temp header paint, but with the bonus of 30x the price. The Swain stuff is THICK, completely different animal.