Ceramic header coatings and performance.

WABBMW wrote:

My son-in-law did the exhaust headers on his RX-7 car. The appearance held up well for a year or two, but eventually began to look sort of powdery or dry and the color faded. Still probably the best coating possible, but will not last forever.

Frankly, I cannot quite see how a performance advantage can be gained, other than perhaps 1/10 of a horsepower.

The way you gain performance is because the temperature stays higher inside the pipe and therefore the exhaust velocity is higher when it hits the collector. This creates a lower pressure at the valves and causes scavenging from the cylinder.

I seriously doubt a ceramic coating will change the gas temp enough to make a measurable difference. The header wrap tape MIGHT make a slight difference, but that will ruin the pipes over time from internal condensation and rust.

They say that it can contain 200*f for everi .001" inside and or outside. This means if you put one thou on each side that is a difference of 400*f contained inside the exhaust and not let to escape threw the pipe. That is the main purpose of the coating.

I propose, if I may, an experiment. Otakar, if you have a temperature measuring device such as an infrared heat gun or a VOM with a temperature probe- Could you measure primary tube temp at the head, collector temp and muffler outlet temp before and after the coating? I know it's alot to ask but I'm curious ........ in the name of science!

I have a temp gun I can do that. It will take a while to get the results because I will make the measurements of the un-plated pipes tomorrow and than the coated measurements in the spring when I put them back on.

otakar wrote:

The Kerker "K" series pipe on my bike has been long discontinued. I love the pipe for looks and performance. two years I had it sandblasted and than I used VHT to coat it. Needless to say that stayed pristine about 1/2 hour before the paint started to bubble and come off. Yes and I did it EXACTLY the way I was instructed by the manufacturer over the phone. VHT of any brand is SHIT. I have been contemplating of getting the header ceramic coated inside and out, so i started to research it on the web. Besides just looks, corrosion protection, and durability, there are significant performance benefits. Especially if you also do it on the inside of the pipes. Because the gases stay hotter inside the pipe the exhaust velocity increases and that increases exhaust scavenging. I have found a local place here in the Chicago area that will do it for about $100, and they do all the prep work. They have it in. silver, flat black, and dark gray. I remember a few years ago WG was contemplating doing it for about $350 for the headers. (I wonder how long that would have taken him to do?) I am planning on removing my header as soon as the riding season is over after Thanks Giving, and taking it in. I have the capability of doing small items like pistons and heads but not something as big as an exhaust header. Anyone here have ceramic headers?

Otakar, I too have the "K" series pipe on my ELR and had thought how I would replace it someday. I am definitely interested in how this turns out.

I find the "K" series pipe "irreplaceable" I don't know which I like better, the "K" pipe or the Yoshi series 1 or 3. The thing I definitely like about the K pipe is the filter access The sound of it is a tie in my book to the Yoshi and MAC pipes. The MAC pipe is fantastic for sound and street performance but the transition between the collector and the tail pipe leaves a bit to be desired in the stiling department. I do love the looks, sound, quality, and performance of the K pipe. The last time I saw it advertised from Kerker it was almost $800

otakar wrote:

They say that it can contain 200*f for everi .001" inside and or outside. This means if you put one thou on each side that is a difference of 400*f contained inside the exhaust and not let to escape threw the pipe. That is the main purpose of the coating.

I don't doubt that ceramics can contain a lot of heat (that's what they use for Space Shuttle heat shield tiles), but did they give any limitations regarding the temp/thickness? I ask because based on their claim, if you put .005" on the inside and .005" on the outside you should be able to grab the pipe with your hand after a 100 mile ride and not get burned. Ed

I found some info on the development of ceramic coatings from some UK company. Interesting read
www.pcimag.com/Articles/Feature_Article/...10000000000000099989

650ed wrote:

otakar wrote:

They say that it can contain 200*f for everi .001" inside and or outside. This means if you put one thou on each side that is a difference of 400*f contained inside the exhaust and not let to escape threw the pipe. That is the main purpose of the coating.

I don't doubt that ceramics can contain a lot of heat (that's what they use for Space Shuttle heat shield tiles), but did they give any limitations regarding the temp/thickness? I ask because based on their claim, if you put .005" on the inside and .005" on the outside you should be able to grab the pipe with your hand after a 100 mile ride and not get burned. Ed

Yeah, I'm wondering about that number too. Ceramic is a pretty good heat conductor which means it's a pretty poor insulator. Hard to imagine it can do that much. They use it on the shuttle because it can operate at temps where it glows (which would melt metal).

bountyhunter wrote:

650ed wrote:

otakar wrote:

They say that it can contain 200*f for everi .001" inside and or outside. This means if you put one thou on each side that is a difference of 400*f contained inside the exhaust and not let to escape threw the pipe. That is the main purpose of the coating.

I don't doubt that ceramics can contain a lot of heat (that's what they use for Space Shuttle heat shield tiles), but did they give any limitations regarding the temp/thickness? I ask because based on their claim, if you put .005" on the inside and .005" on the outside you should be able to grab the pipe with your hand after a 100 mile ride and not get burned. Ed

Yeah, I'm wondering about that number too. Ceramic is a pretty good heat conductor which means it's a pretty poor insulator. Hard to imagine it can do that much. They use it on the shuttle because it can operate at temps where it glows (which would melt metal).

The ceramic tiles used on the shuttle are unsulator tiles. If you think about it, it's the tiles job to insulate the vulnerable skin underneath it from the extreme heat generated by the friction of atmospheric re-entry. Ceramics are thermal insulators with thermal conductivities typically a couple orders of magnitude lower than metals. While there are ceramics that do dissapate heat (ceramic brakes come to mind) the ceramic coatings designed for exhaust systems are insulators

otakar
i also have a "K" series kerker pipe on my GPZ1100 i am going to send it out to JET HOT to have it coated inside and out in black. i just got finished making a comp baffle and end cap for it.