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jdubois

jdubois

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The exhaust header on my Spitfire is starting to show some surface rust, so I was thinking of taking it off when I take the car off the road this winter and sending it out to get ceramic coated.

Anybody have any experience with this and have any place to recommend? The only place I know of is Jet-Hot, but don't have any personal experience with them.
 
Mine has Jet Hot on it. Can't say much as it hasn't had a lot of miles on it. It's not rusty though...
 
I've used both Jet Hot, and HPC, with great success. Blasting is part of their normal prep, so don't worry about slight surface rust.
I've got a complete system here that has never been installed, and I need to get it coated. I called HPC and was told that I needn't concern myself with blasting it prior to shipment. I don't know what the policy is on used stuff, though.
Jeff

https://www.hpcoatings.com/
 
I bought a new set of PaceSetter headers from jet Hot coated on both the inside and outside. I have about 2,500 miles on them and I think that they are great and look good as well.

I would definitely buy from them again. Nice people and great service.
 
My local powder coater is now doing high heat coatings on exhaust manifolds and headers. I had it done on my exhaust header and on an unused header I plan to sell. It looks good, and was pretty cheap. You might check with powder coaters in your area.
 

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David- Are they using ceramics?. There is a difference.
 
I'm really not sure. The coating on the header looks just like the jet-hot coating I had on a small block Chevy header. I think it was ceramic.

It is coated inside and out, and the exhaust manifold has held up well so far.
 
Interestingly, I had my stainless steel headers JetHot coated before I installed them. Now, 4K miles later, they are peeling badly. Guess I could call JetHot but have no plans to take them off and get them re-coated.
 
Thanks for the input guys.

I particularly like the following statement from the performance coating website:

"It has been determined that engine efficiency improves by 1% for every 10° degree drop in under-hood temperature.
If we were to use the above data, we could reasonably assume that we would obtain a 50 horsepower increase on a 500 horsepower engine."

10% HP increase by coating your exhaust header is a "reasonable assumption". Uh-huh. Pull the other one now...
 
Got in late, Had to put a family member down after 18 years, she had cancer, bad teeth, thyroid problems. She was only a cat, but whe was a member of my family.


Anyway. I had my headers sent to Texas back in the latter 80's to get coated(JetHot). They are on their 3rd TR-6. So guess the mileage is somewhere around 100K for them, and in SoCal and Hawaii salt humidity environments. They are still in very good shape. Better than the stainless headers I bought for the FJ1200 about 6 years ago.

My experience is that I would do it again.
 
Brosky said:
I bought a new set of PaceSetter headers from jet Hot coated on both the inside and outside. I have about 2,500 miles on them and I think that they are great and look good as well.

I would definitely buy from them again. Nice people and great service.
Click to expand...

/bcforum/images/%%GRAEMLIN_URL%%/iagree.gif
I have had the same experience and close to 5.000 miles.
 
RonMacPherson said:
Got in late, Had to put a family member down after 18 years, she had cancer, bad teeth, thyroid problems. She was only a cat, but whe was a member of my family.
Click to expand...

Sorry to hear about your cat. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif I've got a sixteen year old that isn't going to last all that much longer, so I know how you feel.


It seems like I won't go wrong with JetHot. So that's what I'll do. Thanks again, guys.
 
jdubois said:
I particularly like the following statement from the performance coating website:

"It has been determined that engine efficiency improves by 1% for every 10° degree drop in under-hood temperature.
If we were to use the above data, we could reasonably assume that we would obtain a 50 horsepower increase on a 500 horsepower engine."

10% HP increase by coating your exhaust header is a "reasonable assumption". Uh-huh. Pull the other one now...
Click to expand...

Remindes me of the old JC Whitney catalogs (haven't seen one in a long time, so I don't know if they've changed), where you start adding up all the 5 or 10% bolt-on HP improvements, and pretty soon your little 4 banger is up to 300 HP (or 100 MPG, if you look at different set of options!).

I have no idea about an temperature benefits of the coating, as I changed lots of things at the same time. I basically did it for the looks, and that alone was worth it.
 
jdubois said:
I particularly like the following statement from the performance coating website:

"It has been determined that engine efficiency improves by 1% for every 10° degree drop in under-hood temperature.
If we were to use the above data, we could reasonably assume that we would obtain a 50 horsepower increase on a 500 horsepower engine."

10% HP increase by coating your exhaust header is a "reasonable assumption". Uh-huh. Pull the other one now...
Click to expand...
Since air density DOES increase by about 1.5% for each 10 degree drop of intake air temperature, provided that jetting is richened accordingly, the statement is PARTIALLY true. Ie. a 100 degree drop of intake air temperature could give 15% power increase.

Since the majority of under hood heat comes from the radiator air flow, header insulation of any type is NOT likely to drop under hood/air intake temperature by very much.

On the other hand, a cold air intake ducted to outside air is entirely capable of producing a 100 degree drop in air intake temperature & a 15% power gain. I think you will find that many serious racers use cold air intakes of one form or another.
D
 
Dave Russell said:
Since the majority of under hood heat comes from the radiator air flow, header insulation of any type is NOT likely to drop under hood/air intake temperature by very much.

On the other hand, a cold air intake ducted to outside air is entirely capable of producing a 100 degree drop in air intake temperature & a 15% power gain. I think you will find that many serious racers use cold air intakes of one form or another.
Click to expand...

Sure, I understand that colder intake air equals the ability for more fuel per charge and therefore more power. But to make the leap from a textbook stoichiometric equation to coating your headers giving you 10% more power as a 'reasonable assumption' is what I was calling them out on.
 
One thing to give credence to; is the isolation of heat from the exhaust under the intake manifold. The cooler the exhaust is, the better the fuel flow in the carbs and manifold will be.
 
RonMacPherson said:
One thing to give credence to; is the isolation of heat from the exhaust under the intake manifold. The cooler the exhaust is, the better the fuel flow in the carbs and manifold will be.
Click to expand...

Not only that, but on these early spits the air intake is in about the silliest position possible. It sucks air from the bottom of the air filter housing, directly above the exhaust! At least on the Mk2 it's a header and not a cast iron manifold like the Mk1. But on the plus side, heat from the exhaust does help warm up the intake manifold quicker and reduce choke usage.

In the later spits they have that funky intake flapper thing with a bimetallic strip to try and get the best of both worlds. In the very late spits ('79+ I believe, maybe earlier for CA) they've got the warm air hose piped directly behind and actually attached to the exhaust manifold. I think they were getting pretty panicky about emissions on warm up at that point.
 
While I fully understand the need for cool air feed to the inlet, I feel that the header is best uncovered or should only have a very thin coating, perhaps more so for a tuned engine.
Some views and reasons on header covering below
[url="https://www.jagclub.ru/lap.html" said:
https://www.jagclub.ru/lap.html[/url]]As the car travels through the air, this header will be cooled in a proportional way to the engine output and the speed travelled.
As speed rises and force air cooling accelerates the gas is cooled faster+faster & expands faster through it.
We are now "doing work" on the gas, - this is good, it also makes it quieter!
This has a reproducive effect on inlet charge & obviously charge density. Ie "the faster it goes, the faster it goes" or what we term "the virtuous curve".
In the meantime, think for a minute...your exhaust tape has THE EXACT OPPOSITE of the desired effect!
Click to expand...
 
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