Thread: Ceramic coat stainless headers?

The title says it all. I know that ideally they should be coated to keep heat out of the engine bay but, I don't want to spend money that has very little benefit. This is my DD that I don't think I will ever go beyond a 3.4 with. I see a lot of members that have ZZP, SSAC or speed daddy headers and just bolt them in. Can anybody educate me as to what I am gaining or losing either way? Please answer with more than a "do it" or "don't bother" response. I am trying to make an informed decision on whether or not to do it. Thanks for any help.

Edit: I'm going to research this topic for a little while and I'll continue to post information that I think may be useful. Please add to this discussion if you like.

the point of having stainless is so that you dont have to coat them. one of the big reasons for coating non-stainless headers because they are mild steel and they'll rust. with headers being so much thinner than the stock manifolds enough rust will completely destroy them.

heat retention from a ceramic coating isnt all its' cracked up to be. it helps, but the gains are very marginal.

Thanks again bio. Exactly the kind of feedback I was looking for. I didn't want to do it if the gains were minimal.

show me proof of coating being worth it for the money it costs.

Originally Posted by minichopper6hp

The gains of ceramic coating have never been about rust... its to keep the heat IN the pipe. Your engine bay will suffer if you dont coat or wrap them. Also, they dont stay shiny long.

Thanks for the feedback minichopper. I knew about the ceramic being for heat control, but wasn't sure what the gain was. As far as the shiny goes, I don't really care about that part. I was going to use Swaintech if I was going to ceramic coat. If you are not familiar with them, they are more about function than looks. Only question left for me now is do I go cheap (speeddaddy) or expensive (zzp).

Found this a few minutes ago trolling around on the internet. It was posted on the performance welding racing headers website.

Stainless Steel vs. Mild Steel

A very popular question concerning the use of Stainless steel over Mild steel in a Competition Header application constantly arises in the industry. Stainless Steel is a better choice when Header lifespan, updates, and quality are an important consideration. A Stainless Steel Competition Header, when properly built, will virtually last you a lifetime.
A Mild Steel Header in a Competition application will soon take its toll from the elements of high exhaust temperature and rust. Performance Welding has tried many Exhaust Coating manufacturers and have found none that will withstand the extreme temperature of a competition engine. On the inside of the primary tubes and at the throat of the Merged Collector, the thermal barrier coating simply cannot withstand the high temperature and after a very short period, the coating burns off and rust begins to generate.
This rust can be disastrous to any engine and can ruin many components.
On initial overlap, there is an inevitable reversion pulse that can send exhaust back up the intake tract. If the rust loosens in the header primary tube it can, and sometimes, will carry some of this abrasive material into your cylinder.
It is highly advisable after leaving Mild Steel Competition Headers over a period of time to take any precautions to remove the rust build up; on initial engine start up this rust can be disastrous.
Stainless Steel Headers have many benefits outweighing the initial cost increase. Due to the fact that they do not need a Thermal Barrier coating you save a few hundred dollars on the initial cost. Stainless Steel Headers can be repaired, or modified at any time in their lifespan due to the simple fact that they do not rust and do not need a Thermal coating. Mild Steel Headers are very tough to repair or modify due to Thermal Coatings and rust.
It is believed that due to Stainless Steel Thermal characteristics, the high exhaust temperature is retained inside the primary tubes and can increase the exhaust speed in the header, which in a Competition Racing Header sometimes is an important goal. Due to the simple fact that there is no rust generated, the inside of each primary tube will stay smooth and flow accordingly.

Performance Welding Racing Headers feel strongly about the use of Stainless Steel in your Competition Header application. If you have a Race vehicle that you truly wish your Competition header to last a lifetime, or if we have a proven Competition Header for your engines combination, or you simply like the benefits of Stainless Steel we highly recommend it in any Competition Header application.

- Mark Lelchook / Owner

hm....weird...

good read

very good read, I feel educated now

its almost like i knew what i was talking about.

minimal gains at best. scavenging is the only thing it helps.

Originally Posted by minichopper6hp

The only thing that article is saying is that you dont HAVE to have coating on stainless to keep them together. It is still beneficial to coat them to keep the heat out of the engine bay.

^ Based on logic, I absolutely agree with this but, for me it comes down to what do you gain for the cost. If money was no object, I would probably get it done because it would make me feel good.

I don't know enough to argue for or against coating, but I can spend hours reading different sources and form an opinion based on information from sources that seem to be legit. The more I read all over the internet, the more it seems the gains from ceramic coating stainless is minimal gains. One site I read even gave a number about how much better stainless was than mild steel for headers. If I remember right, they said said mild steel conducts heat 219% better than stainless. I'm no expert, but I think for my use, I will probably not coat them.

Here is some good reading regarding header wrap for those interested in the topic: Century Performance Center, Inc. :: Exhaust Header Heat Wraps - DO NOT USE

Found another article on Turbo and High Tech Performance talking about stainless:

What are some of the main differences between mild steel and stainless steel when dealing with temperatures?
JB: Stainless steel has a better high-temperature strength than mild steel. In a normal header situation you can go to lighter gauge stainless then mild steel so you can save weight. In a turbo application, where you have much higher temperatures than a naturally aspirated application, same deal applies.

VR: The other good deal with stainless is you have a lower coefficient of thermal conductivity so it tends to insulate, whereas mild steel tends to let the heat travel through the metal quickly. Also, a lot of people will use a ceramic coating to reduce the heat transfer but stainless does this inherently.

JB: Then there may be long term durability problems with some coatings. As a matter of fact, one of the main drawbacks with carbon steel is that once it's overheated, it will start to flake and fall into the turbo. The same goes with the coating. This will also flake. I would say coating isn't useless but if you want to lower your radiant temperature, then stainless is the way to go. It can reach the same surface temperature as mild steel, but stainless will stay hotter on the inside and transfer the heat.

What about rumors that stainless steel cracks easily?
JB: The material isn't the cause of the cracking. In most cases in a turbo application, it's the manifold design that causes cracks. Most people don't allow for the thermal expansion with stainless, which is 50 percent greater than mild steel.

VR: What you have to keep in mind is most people will have a manifold that has the primaries fairly straight and then you add support between the head flange and turbo. This doesn't allow the stainless to expand and it causes stress on the tube. Supporting the turbo is a good thing, but you must compensate for expansion of tube by adding a bend area in each primary equally so you allow flexing and stretching to occur.

JB: With a lot of the manifolds you see on the imports, the turbo is mounted very close to the head. When the bends come in at different directions this will cause the manifold to crack at the collector because everything is expanding in different directions.

From Quick Time Performance:

Made Only In Stainless Steel
Stainless steel is non-magnetic, a quality that makes them very important in the aerospace industry. Compared to mild steel, stainless steel has superior high temperature characteristics. It is an excellent material for headers and any application where high heat is encountered.

You may have heard talk about maintaining high exhaust velocity and increase scavenging by covering headers with a thermal wrap. In addition, there are companies that coat headers with a thermal barrier, typically some type of ceramic formula, in order to keep the heat inside the exhaust system.

Stainless steel performs this function without the need for add-ons because it has a much lower coefficient of thermal conductivity, thereby keeping more heat inside and transmitting it to the header outlet. Radiated heat is perhaps the most important reason to wrap or ceramic coat the headers to protect the car and the driver from excessive, fatiguing high temperatures.

Typical 1010 carbon (mild) steel conducts 219% more heat per foot than do the types of stainless steel we use in header fabrication. By contrast, quite a bit more heat stays inside the stainless header tubes and does not get passed into the surrounding air. By not allowing the contraction of the cooling gases as they flow down the tubes, more exhaust velocity is retained which promotes better scavenging at the collector.

This retention of velocity increases the overall header efficiency. 304 stainless steel has excellent high temperature fatigue resistance in enclosed application and does a darn good job of living in this hostile environment better than any other material.

These many characteristics, such as superior heat retention properties, high temperature fatigue resistance, and to a lesser extent, the cosmetic value of a non-rusting finish, combine to make stainless steel an ideal choice for headers. Our system will produce more horsepower and last "'til the cows come home"

The more I read, the more I think bio and minichopper are both right. From a pure performance aspect, it seems ceramic coating on stainless will give a minimal performance gain if anything at all. As far as what's better for your engine bay, ceramic coating will keep down your underhood temps and help make all that wiring and plastic last longer.

Everywhere I read, the header "experts" seem to be in agreement about wrap. Don't use it. I have not found anybody who makes headers that supports wrapping them. Some jokingly encourage you to do it though so they can sell you another set of headers sooner.

I'll keep reading and adding to the thread.

From an interview of Jere Stahl and Billy Boat by Stock Car Racing Magazine:

Racing Headers - Advice For Saturday Night Racers - Stock Car Racing Magazine

SCR: What about ceramic coatings versus chrome or nickel?

Boat: Chrome plating is OK for show cars and bikes, but it has no place on racing headers. Nickel is not a real option, either.(Note: There are some data points out there that indicate some brands of coating actually increase horsepower. But the impact of coatings on durability is still an unknown at this point. -J.H.)

Stahl: The so-called ceramic coatings look nice. I have no hard data that confirms or denies if they add life to a header. The problem with these coatings is if for any reason you have to weld the header at a later date, the coating has to be removed; that's not something most guys can do at home. I will tell you that the header wraps that are on the market are the header manufacturer's best friend. The only way you could kill a header quicker is with a gun. Chrome plating can cause hydrogen embrittlement. So unless you are ready to bake the headers for multiple hours, chrome plating is not a real option. Nickel is not an option, either.