Jet Hot Coating
Thread Starter
Safety Car
Joined: Mar 2006
Posts: 3,953
Likes: 274
From: Cedar Falls Iowa
Jet Hot Coating
Does jet hot coating cause a reduction in the effective inside diameter of the header tube, maybe driving you to select the next larger tube size (1 7/8 vs 1 3/4)?
Does jet hot coating reduce the frictional coefficient of the surface that it is applied to (making it smoother, filling in the rough weldments), resulting in an improvement in air flow and exhaust efficiency?
Is there any tendancy for the jet hot coating to bubble up or flake off of a stainless steel header surface?
Does jet hot coating reduce the frictional coefficient of the surface that it is applied to (making it smoother, filling in the rough weldments), resulting in an improvement in air flow and exhaust efficiency?
Is there any tendancy for the jet hot coating to bubble up or flake off of a stainless steel header surface?
Race Director
Joined: Jan 2006
Posts: 18,396
Likes: 169
1. No
2. Somewhat, but the big advantage is the coating keeps the heat in the tube, which helps accelerate it out, plus, there is less radiated heat inside the engine compartment.
3. No
If you're running cats, the coating will help heat them and the O2 sensors quicker than a non-coated header, with less likelyhood of a CEL.
2. Somewhat, but the big advantage is the coating keeps the heat in the tube, which helps accelerate it out, plus, there is less radiated heat inside the engine compartment.
3. No
If you're running cats, the coating will help heat them and the O2 sensors quicker than a non-coated header, with less likelyhood of a CEL.
Racer
Joined: Mar 1999
Posts: 316
Likes: 0
From: Waterford NY
Skinny on "Jet Coat" ceramic TBC Coatings applied to headers
1. No
2. Somewhat, but the big advantage is the coating keeps the heat in the tube, which helps accelerate it out, plus, there is less radiated heat inside the engine compartment.
3. No
If you're running cats, the coating will help heat them and the O2 sensors quicker than a non-coated header, with less likelyhood of a CEL.
2. Somewhat, but the big advantage is the coating keeps the heat in the tube, which helps accelerate it out, plus, there is less radiated heat inside the engine compartment.
3. No
If you're running cats, the coating will help heat them and the O2 sensors quicker than a non-coated header, with less likelyhood of a CEL.
I am a High Temperature Metallurgist, worked on OEM and refurbished gas tubine and jet engine hot zone components since 1970.. and specifically have developed various high temperature Diffusion Coatings for Industrial Gas Turbine and Aeroderiveative Gas Turbine (Jet Engine) applications. Also, I am quite familiar with "Jet Hot Coatings" ususally, 8% Yttria Balance Zirconia (YSZ, Yttria Stabilized Zirconia) which are ususally applied by Air Plasma Spray (APS) to an M-Cr-Al-Y HVOF High Velocity Oxy Fuel) or APS applied bondcoat over the (header) base metal/substrate.
One application I witnessed at a company at which I was doing metallurgical consulting, was the application of bond coat's and TBC's to NASCAR Vehicle Headers, 358 ci, Chevrolet, Ford and Mopar engines, as I recall.
The effect of "Jet Hot Coating" which are actually Ceramic, AKA Thermal Barrier Coatings (TBC's). whether applied to improved carbon Specialty Steels such as by Bassani, Kooks, and AR (I believe) and many others, or to Stainless Steel substrates such as Random Technology and others...is to lower the temperature of the header by "insulating" and reducing effective thermal emissivity. This basic coating property has the following net effects:
1) Exhaust gases are hotter and flow faster (more kinetic energy) and therefore are extracted faster as EuroRod has correctly pointed out;
2) Radiant heat into Engine Bay is subsequently reduced, and Intake Temperature effects into Throttle Body are improved, i.e, Tsub i reduced..this means more power/torque for given amnbient conditions, other factors being equal (air density, altitude, ambient humidity, ignition timing, AFR etc. etc.)
3) Most TBC coated headers per se or with an high flow (MetalCats as an example) X- Pipes for streamling flow and an axial orientation in the Cat back exahust portion, (C-6 design as opposed to C-5 design...Corsa is better than Borla for C-6 in this regard)...sound better..i..e, more aggressive without being annoying...although as has been pointed out many times before...this is a subjective observation.
4) Bottom line..IMHO. TBC coated Kooks or Random Techheaders are a good "bang" for the buck...effective diameter is increased compared to non-TBC coated headers since flow/gas velocity is better.
That's my $.02.
Comments, gentlemen?
Best Regards,
Bernie
Last edited by BernieR; Dec 25, 2006 at 08:06 PM.
Thread Starter
Safety Car
Joined: Mar 2006
Posts: 3,953
Likes: 274
From: Cedar Falls Iowa
Thanks bunches for the responses guys.
Seems like these kinds of things get debated quite a bit w/o much more in the way of technical support info than personal opinion. I'm good to go with when the opportunity arises.
Seems like these kinds of things get debated quite a bit w/o much more in the way of technical support info than personal opinion. I'm good to go with when the opportunity arises.
Racer
Joined: Mar 1999
Posts: 316
Likes: 0
From: Waterford NY
[[U]B][I][U][SIZE="3"][COLOR="Blue"][B]Good Evening Barking Dog,
The benficical performance advantages of TBC (Jet Hot Coating) to increase exhaust gas Temp inside the header ID, whilst simultaneously reducing engine bay temperatures IS NOT AN OPINION. THIS IS MATURE TECHNOLOGY AND HAS BEEN AROUND FOR 25 YEARS AT LEAST.I happened to be at one of the companys that first applied these coatings when I was working on Chrome-Aluminide and Palladium Chrome Aluminide Diffusion Coating development for Industrial gas Turbine and Aeroderiveative Gas Turbine Hot Zone Components.
Nothing new here.....happened to be there....now I'm still working on advanced coatings, instead of being retired...not out of choice but because of bad luck/poor smarts in the stock market in 2001/2002 timeframe
Whatever...still got mah Vettes and mah family!! so I'm Blessed and Rich too!!
Later 'bro,
Happy Holidays...wooooooooooooooo that rum and limeade is goooood!
Bernie
Last edited by BernieR; Dec 25, 2006 at 08:25 PM. Reason: typos and pooooah spelling, as usual...
