Podium

iTrader: (2)

I am up in the air about coating my SS headers. Very interested in reducing heat, but not interested in ruining the headers. I have found horror stories of headers rusting (nonSS). Jet hot says "clean and polish your headers to ensure longevity." Sorry, not going to clean and polish my headers all the time. The only thing I read is if you're going to coat headers, SS is the way to go. Although Kooks and American Racing says not to, but that could be them covering their butt if something goes wrong.

My local powder coating guy has been coating exhaust for 15 years and swears buy it. He also told me that coating the inside is pretty pointless.

Thoughts?

sofakingdom

iTrader: (1)

Lots of confusion here. Let's start with the basic physics of how these things work, and go from there.

Headers produce their benefit by way of the exhaust stream through them, which has mass and therefore inertia, getting started at the beginning of the exh stroke when cyl pressure is still very high; and the inertia of the gases rushing through them at high velocity, continues to extract exh gases from the cyl later in the exh cycle after the pressure has fallen too low to maintain continued cyl evacuation on its own. The main points being, leftover exh gas in the cyl poisons the next int charge, reducing its heat (power) output; and, to the extent that the cyl pressure is above hard vacuum, it impedes the flow of intake charge, reducing the amount of mixture that makes it into the cyl in the first place. Manifolds are therefore a double whammy to engine power output compared to headers.

Stop for a minute and think about that for a minute or 2, until you clearly understand what is going on.

OK, now that you have it firmly in your mind, you can see that you want to keep the velocity of the gases in the header tubes as high as possible.

Now, if the gases cool, they shrink; if they shrink, then they slow down; so any cooling effects that headers have, reduce their effectiveness.

Not all metals conduct heat at the same rate. Specifically, stainless conducts heat less than half as well as carbon steel. http://en.wikipedia.org/wiki/List_of_thermal_conductivities Look down the list and find the 2 materials. This means that for a given thickness of metal, more than twice as much heat will escape through a carbon steel barrier than a SS one, all else being equal. Right off the bat, this means SS is a superior material for headers, purely in terms of its effect on engine operation.

Ceramic coating adds an additional layer of insulation, thereby keeping more heat in the gases. Its thermal conductivity is VERY poor, therefore a relatively thin layer provides a significant reduction in heat loss through whatever it's applied to. http://www.researchgate.net/profile/...158c000000.pdf This means that not only does the coating offer its anti-corrosion benefits, but also it improves engine performance.

Coating the inside of the tubes DOUBLES the insulating effect of the coating. This NOT ONLY improves engine performance, BUT ALSO prevents excessive heat under the hood, thereby extending the life of rubber, plastic, electric, etc. components, all of which tend to crumble to dust rapidly if subjected to the heat released by typical cheeeeeeeep headers without coating.

There is no "need" to "clean and polish my headers all the time" if they're coated, any more than there would be if they're NOT coated. All they're trying to tell you is, foreign matter on the ceramic may deteriorate it, same as it would anything else. Think, the effect of road salt for example. Washing it off occasionally, the same as you should be doing anyway to your engine and suspension and whatnot (besides all the shiny things on top you're accustomed to wash already), will preserve it, same as keeping everything else clean will help it last longer.

"Stainless" steel isn't "stainless" under all conditions, like you're accustomed to thinking about your forks and spoons or something. There are MANY alloys of it, all of which behave differently. The ones used for exhaust do in fact corrode, but the corrosion is self-protective, unlike rust. That is, it's very hard and durable, so once a thin layer of it is created, it stays put and doesn't flake off and expose more metal to corrode the way regular cast-iron or steel does. SS headers and exh pipes turn a kind of chocolate-brown color after a short time. The ceramic coating stays shiny silver--metallic looking (or whatever color you get) pretty much forever.

My advice remains, get SS headers, and have them coated inside and out.

Podium

iTrader: (2)

Not confused about how it works, just the longevity and how it will affect my headers in years to come. Thanks for the detailed response.

I just wanted some extra info before I coat my 1100 dollar headers.

HeinzK5

I ceramic coat exhaust stuff and have seen lots of failed jet hot stuff its only good for 1300 deg and it has to be polished to keep the shine and that takes some of the material off. we use the cerakote high temp line of coatings there good to 1800 deg and they have a new line called glacier series that's good over 2000 deg, now all of these are satin to flat finish. The benefits are way better than rusty pipes. Just ask your local Powder guy he probably use the same stuff.

LB9GTA

iTrader: (1)

I bought shorty hedman headers and got them coated when they were new, (best time to do them!)

I sold them about 7yrs later, and they still had the coating on them, granted, they had some rust too. But, if you didn't get them coated, I would imagine that there would have been ALOT more rust!

Then I bought a $800+ set of Ed Quay headers. I got them ceramic coated immediately after I purchased them.

The coating helps with longevity, reduces under hood heat and helps with more power. Plus you can get them shiny too.
I don't see a downside.

Both headers were not stainless steel.
And both were coated on the inside

LB9GTA

iTrader: (1)

luvofjah

iTrader: (2)

I bought my Hooker 2055's and y pipe from Jet hot.
No problems and enjoying the reduced heat in engine bay...
They have a lifetime rust through replacement warranty.
Not sure if that is if you buy it through them, as I did...
Check and see...

Ozz1967

iTrader: (4)

I bought a pair of hooker 2055's and after moving to Utah in 2008 where it snows and I might get get corrosion on them from that, I took them down to HPC in draper and had them HPC coated (parent company that Jet Hot Spun off from years ago). Went to England, drove there year round as well as Germany, Ocean crossing there and back. My headers still look good but I've had to replace the exaust I put on at the same time this last year, the aluminized muffler (Aerochamber) and 3" piping just broke to pieces when I pulled dropped the exhaust to change my fuel sender.

anthony64ss

iTrader: (1)

You can't go wrong, worth every penny when done right. I don't really think there is any downside to coating, plenty of finish options if you don't like the polished look.

The amount of heat reduction is awesome, esp for a carbed car. I remember being able to grab my coated stainless slp shorty's with bare hands within 10-15min of turning the engine off. No more heat soak or vapor lock and the finish holds up great.

I think I'm going to get my L69 manifolds coated in cast iron this spring, should turn out great...if anyone is in cali Cap's Brite Hot does great work.

formula1LE

iTrader: (3)

I can't recall the name offhand but the guy that worked with Smokey Yunick on his hot vapor engine still maintains a successful ceramic coatings business-I'll see if I can find his info....Smokey knew a thing or two about ceramic coatings too.....

formula1LE

iTrader: (3)

http://swaintech.com/race-coatings/r...aust-coatings/

And iirc, he was a key player in the development and testing of the ceramic heat tiles which were used on the space shuttles. Before this guy, ceramic technology in the automotive world was viewed as fanciful.

Ozz1967

iTrader: (4)

Older post here, but still relevant. I have been researching header coatings now that I'm in the middle of my LS Swap. I'll be going with the Holly Black Heart Stainless headers.

The interesting thing about Swain Tech, a company that pioneered this and is very well known in the Turbo Market, they don't coat the inside of headers. Mostly because they can't. The way their product is applied they can't get into the primaries to apply it. That said, for a stainless set up that basically will never rust away for the life of your car this is fine. For mild steel applications I'd suggest Jet Hot or HPC as they can do the inside.

Here is an Article in hot Rod for those of you debating on whether doing the ceramic coating is worth it or not. In this article they used the Jet Hot coated vs factory painted headers. The performance increase (Hp/TQ) was around 1% on a BBC crate motor but the header temps dropped 50% on the coated vs uncoated headers. This is a HUGE number. Especially when considering the amount of under hood temps you can potentially see in the summer.

High Tech Ceramic Coating article in Hot Rod Magazine