Ceramic Coating Exhaust and WUR question

FYI, I had "Jet-Hot", a well known company, coat my headers after removing the outer shield and insulation. It started peeling after maybe 1-2yrs. Total junk.

 

The warm up regulator has an internal heater. The ambient heat really has no effect.

 

It peeled off my Alfa Spider and Scirocco too.

 

I believe their HP gain claims are bogus, but do they actually reduce surface temperature?

 

Intersting. I have Jet-Hot polished silver coating on 3 different cars, one for over 20 years, the most recent one done 3 years ago, with no issues at all. Makes me wonder if they changed hands or otherwise have lost their focus on quality preparation. I believe they have two different locations. All of mine were done in their Oklahoma facility.

 

I think it depends on who and how its done. I had a shop ceramic coat a Ranger header as a test to see how it would last. With in a few weeks the surface turned to "chalk board" texture. But a buddy had the same shop do the entire exhaust on a Ultima GTR and it looked brand new for years.

 

Maybe Jet Hot is using a different process to apply it's coating, the headers on my occasional track day Alfa still looks awesome after 20+ years. No peeling whatsoever.

 

I have been researching some of these coatings lately. I'm not a pro but here are some things I've learned -

All options of coatings have multiple effects:

• By keeping the outer layer (and inner wall) insulated it creates a cooler environment for the gasses, which allows them to flow faster. Will it add power? I wouldn't imagine anything noticeable, except for perhaps less performance drain over prolonged hard usage, like on track.
• Internally it protects the exhaust metals from deterioration, fatigue and aging from heat cycles in use. Externally, they protect the same from outside factors.
• They protect other engine components from heat soak, thus preventing the same deterioration and fatigue, also keep regular function.
• Unlike wraps, which are effective, they will not trap in moisture, shortening the product lifespan.

Main product options:

• Jet-Hot on headers and exhaust pipes - of the coatings, less a couple more high end options, this works pretty well. It has to be done by a professional. You have options of internal pipe coating, as well. It is applied like a powder coat and baked.
  
• Cerakote - (pronounced like the name Sarah Coat) Cera is short for ceramic. This brand has high temp options like Jet-Hot. These can be done by professionals. They also sell their coatings to the public and if you have the right space equipment and skills, you can do it yourself. It also requires baking as a part of the application.
  • They also have a number of coatings that can be applied for nice protective surfaces, not requiring such high temp requirements. Lots of cool products now have these coatings from other engine parts, firearms, industrial equipment,etc. They make a nice strong finish and not all require baking.
• As noted in a post above - like painting, much work has to be done in prep to get a good result - lots of cleaning and degreasing.
• Also don't forget some VHT / High-Temp paints - not nearly as durable or protective but they exist.

Other options:

• There are some new, very expensive shielding options that are very effective but they do look out of place on classic cars, in my opinion. Those are the dimpled foil looking product.
• I just pulled my front bank header in the factory metal shielding - all battered and hand hammered. but nothing like a good shield to deflect heat in an engine bay!

I just got a new engine and transmission for my project. I am cleaning down the bare aluminum finish. I love the way it looks and i think I never want to put in that effort again, so I have been looking at all these options. I want to have it look like the natural finish but have something I can more easily clean off. Chevy orange like on the small blocks? - Haha just kidding!!!!

Cheers,
Spencer

 

Insulation prevents the transfer of heat from the exhaust gas to its environment (i.e. the manifold and further on the engine bay). Thus the exhaust gas stays hotter and less dense. Lower density means that more volume has to be moved - i.e. more drag in the exhaust system. This reduces the volumetric efficiency and thus the power of the engine.
On the other hand keeping the temperature of the engine bay down may keep the intake air slightly cooler, which is good for the volumetric and thermodynamic efficiency ... i.e. more power. Whether the net effect on power is positive or negative might depend on dozens of factors, which may vary widely depending on the car and environment.

Bottomline: If someone tried to sell me an exhaust coating which increases engine power, I'd be rather sceptical. Just my USD 0.02 (but i have been wrong before).​

 

Terrible to hear that the Jet Hot is failing. I have 3 cars with it, all over 20 years old and one of them was run on the track all look great. I've never measured temps. My primary interest was to simply protect the original header systems.

Just curious if Jet Hot provided any support like re-coat etc.?

 

Coating are mainly aesthetic on SS but also corrosion protection on mild steel. Sure they do provide SOME insulation, but nothing like wrapping or the factory heat shields provide. They look great though for sure.

 

They have a lifetime warranty, but if they couldn't get it right the first time, do I really want a repeat? Plus, it means I can't use the car for 2 weeks, I have to remove it, I have to buy new gaskets, I have to pack and ship it, etc. It's like being offered a free proctology exam because the doctor has some extra time. Mine was done at least 10 yrs ago, so if they did change their process it was awhile ago. Maybe the 308 headers being stainless is an issue? BTW, I said it peeled in 1-2yrs, but I think it was actually faster. First it cracked, then lifted, then flaked. And the flakes deposited on any greasy or oily part in the engine bay, so not pretty. I'm driving this car pretty calmly back and forth to work. Almost no traffic. Few traffic lights. No track use. If it can't handle this easy driving environment, what can it handle?

I have a lot of experience coating stainless in Alumina(a type of ceramic) using the same process used to coat jet turbine blades. It's very specific but very repeatable and reliable if done correctly.

Two locations: OK and NC. I used NC.

 

Stainless is not an issue with Jet Hot coating. My cars with Jet Hot all have stainless systems. One of my cars with the oldest Jet Hot header coating (a track prepped Lotus Elan with high output engine) has had extensive time at high load/high rpm running over the last 20 years along with 25k miles of road driving. And those headers had been in use for a decade or so before being coated. With all that, the coating has lost just a bit of luster. Most people think I just had it done.

I have black Cerakote on my 308 factory headers at present, and after the first shop applied the coating it was flaking off during the install! After getting everything installed, I changed course, bit the bullet, removed the headers and all the other **** again and took them to another shop, who pronounced the prior prep work was sub par and refinished them, with the same Cerakote product. So far it's only a year and about 800 miles, but the new finish is holding up well. For me it was worth the hassle and down time, but I understand the reluctance to begin a do-over.

 

I hear ya!! I went through a real pita w wheel paint where Mg treatment was poor.
Remove wheels, remove tires, send rims out for chem strip, send rims for Mg process, tires reinstall
Yuck!

This is the deal to care for these great machines. It's so nice when everything goes right. But occasionally it doesn't .

Who did the Cerakote successfully?

 

35+ years can ruin surfaces.
Every paint master I meet tells me preparation is the needed trick.
There are ceramic rattle can for exhust too.Not 2k but not expensive. If expensive jet hot will fail then is rattle can fail any worse for $10 and you can do it at home frequently years if you want?

The difference is the effort to remove the exhaust parts. Have not done it on my 328 so unsure how much time this effort is.

 

It's not something you'd want to do just to touch up some paint.