Wrapping the headers...

[Schrade]

Anyone know much about it? Pros? Cons? Tips? Mine are finally about to go in here...

Does wrap keep the heat better than ceramic coat?

[We Gone]

I would rather have them coated, Never liked the looks of a wrapped header after a few years the wrap gets lose and stained. As far as functionality the wrap does as advertised.

[Hog]

Wrap can also hold moisture when not running. It will also void pretty much any header manufacturers warranty.

Back in 1999 I bought a set of Hooker Competition Series headers for a daily driven truck. These headers were were mild steel with a ceramic coating. Previous to tehse ceramic coated headers, I was using a set of factory black painted headers which of course had it's paint come off during the very 1st warm up cycle.
EVery Spring for 3 Springs straight I had to replace the headers as the primaries would rust and then fall apart.

The coated Hookers were almost double the same header uncoated or about 3 times teh price of the painted Hedmans I was originally using. That truck was daily driven until roughly 2011 even during our highly roadsalted Canadian WInters. After many hundreds of thousands of kilometers the Hookers have yet to rust through, although the coating is far from pretty underneath the truck. I had heard that Jet Hot did the coatings for Hooker back in those days, but Hooker has changed coating suppliers, or at least have changed the coating formula itself. My experience was positive, but I cant recommend wrapping headers on s street car. Maybe on a turbo race car?

The idea of keeping the thermal energy inside the header itself, this keeps exhaust velocity up, which promotes better scavenging. That's the theory, but I have no idea how much keeping the heat inside the header will actually help power production in a performance street application, aside from of course keeping underhood temps down and preventing "thermal injuries" to plastic and other parts

[Paul Workman]

The idea of keeping the thermal energy inside the header itself, this keeps exhaust velocity up, which promotes better scavenging. That's the theory, but I have no idea how much keeping the heat inside the header will actually help power production in a performance street application, aside from of course keeping underhood temps down and preventing "thermal injuries" to plastic and other parts

Color me skeptical too: I realize I'm swimming upstream in a flood of "header sales hype", but considering the velocity of the exhaust gasses at any throttle setting where headers are making their max power, there simply isn't going to be much heat transfer. There just isn't time enough.

Schrade: Besides, there are other physical factors like cross sectional area of the primary tubes, the length of the primary tubes themselves, the shape and length of the collector, the diameter of the exhaust pipe, X-pipe size and design...ALL having very immediate and significant impact on scavenging of the headers. I haven't run the numbers, no. Cliff or Todd or I can do it, if you want to see it, but my gut will betcha a ham sandwich the gas temp between the un-coated/un-taped primary tube inlet and the outlet of the (SW) LT5 headers at WOT is going to be puuuuurdy small!

If one wants to reduce heat radiation, and ceramic coating is out of the question, then go for it. But, I too ain't buyin' the notion that scavenging via heat retention (in any meaningful way) to be a serious consideration.

No biggie. Far as heat radiated into the car, mine are not coated or wrapped, and only have the stock heat shields in place...No problem w/ radiated heat (for me), and the same can be said for noise. And, as far as esthetics go, the headers are tucked down between the frame rails and the cam cover so that only the tops of the header tubes peek out to where they can just barley be seen in the shadows. Not worth coating on that score either, sez me.

Your mileage may vary.

[Karl]

Paul, how long have you been using non coated stainless steel headers? Any problems with normal wear and tear?

[4-cam]

Here is a link to a test Cerakote did on ceramic coating.

http://www.cerakotehightemp.com/testing/

It does show the coating to have some pretty good insulating properties along with feedback from others I decided to do it.. I had my SW headers coated as it cost $215 here from a local vendor. With the cost of the better quality wrap being quite high and the time involved to wrap them, I thought that $215 was a bargain. I’m sure some will argue different brands of coating are better than others, and that may be true but I’m not going to start a comparison. Mine was reasonably priced, feedback was very good from others, and they were local and did a nice job.
I agree with Paul that the velocity is so great that the heat loss, although present should be minimal. I’m sure there is can be some kind of performance gain but could it even be 1%? Not a good ROI if you’re looking for HP I don’t think. JMO

[Paul Workman]

Paul, how long have you been using non coated stainless steel headers? Any problems with normal wear and tear?

4 years now. They're holding up beautifully! I DID fly off the end of the runway at Bult field, but far as I can tell, the headers did not absorb any of the rough stuff (mostly confined to the front bumper and the frame "horns" that support the bumper and radiator).

[rkreigh]

get em coated. wrap is a PITA and not that much more effective

it can kill a set of headers pretty quick too. on my old turbo buford (admit a MUCH higher EGT) the headers just shattered like glass after being wrapped for 6 months

any oil leaks can soak them and catch on fire.

not worth the hassle and risky!

[PhillipsLT5]

coat em

[Schrade]

Cerakote is PAINT? Is there anything crystalline about it?

'Ceramic' had me thinking this stuff is a mineral or metalloid (at worst) coating from a MOLTEN temperature immersion. Like porcelain - stone-like, to keep it simple here...

Anyone got MSDS for this ... paint?

[Schrade]

I'm kinda' surprised here.

This 'ceramic' coating - not actually ceramic, in the chemical or physical sense of the word - is an ORGANIC compound.

Makes me think of how North Carolina (and maybe some other states), calls candy bars 'Non-Food' - a political device to generate revenue for non-food tax. But what's in a name...

Ceramic??? Hmmm..................

Seems like this stuff is more of a high-temp paint, than a mineral coating. It DOES have Silicon in it, but not much. I suppose it DOES hold heat better than nothing, but no way it can hold heat better than wrap...

Found this in one of my college Organic Chem books:

... physical degradation by oxides of Carbon (that's Carbon MOnoxide, Carbon DIoxide - both present in exhaust gases), silicon oxide, formaldehyde.

Heat HAS TO accelerate breakdown...

[4-cam]

Several manifacturers make a simular product with very good results used for many years. Were not reinventing the wheel here. A major diesel performance shop by me uses these products every day with great results. The environment they operate in is much harsher than ours will ever be. Wrapping is a major pia so most chose to coat but it may fit your needs....

BTW I just fired up mine last night with the new exhaust/headers and its sounds nasty!! Ill post up a clip later.

[edram454]

jet hot coatings. they have a new finish that is like chrome. will hold up a very long time and look great. wrapping holds moisture and over time will damage your expensive headers. The headers are expensive not only with there cost but the installation is a bear. coat them and use a quality header coating company. Jet Hot is a NHRA sponsor and if those guys cant blew that coating off, trust me , you cant either. good luck.

ed ramos #3028

[Bob Eyres]

I think that comparing cheap, mild steel headers to stainless is like apples and oranges. It seems to me that ceramic coating the cheap ones would almost be required if you wanted them to least more than a couple of years.

I've had my Watson stainless headers, (not coated or wrapped), on there for almost twenty years now, and they're holding up well.

I would like to see a test to determine if coated headers actually lowered underhood temps in a ZR-1. We just assume it does.

[mike100]

I've had my Watson stainless headers, (not coated or wrapped), on there for almost twenty years now, and they're holding up well.



I can't think of any oem applications that ever had any kind of coated manifold either. I'm not sure there is too much to gain thermally for the cost.

I bought my headers used and I went with the bare finish for stealth reasons anyhow...plus no additional cost obviously. I once bought a replacement jeep 4 liter manifold from Banks, and then later, Doug Thorley. both replacements were ceramic coated, but it seemed to just look nice. The only reason they made a small amount more power than stock was the tubing design improvements, certainly not due to heat retention. Probably the pipes would last longer uncoated anyhow as they will shed heat and survive.

[Hog]

I think that comparing cheap, mild steel headers to stainless is like apples and oranges. It seems to me that ceramic coating the cheap ones would almost be required if you wanted them to least more than a couple of years.

I've had my Watson stainless headers, (not coated or wrapped), on there for almost twenty years now, and they're holding up well.

I would like to see a test to determine if coated headers actually lowered underhood temps in a ZR-1. We just assume it does.

I dont think anyone is comparing cheap mild steel headers to stainless steel headers, I do agree that that would be an "apples to oranges comparision"

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If the stainless steel is made of quality stainless steel, there shouldnt be an issue whatsoever with corrosion. Esp. on a vehicle that will never see a hint of roadsalt, such as the beauties that grace this forum.

Stainless steel's thermal characteristics apparently act in a similar fashion to a mild steel header with a coating.

The only degradation that could be experienced would be a broken weld, or piping failure from thermal effects.
So long as you use a quality stainless steel, the header should last the lifetime of the vehicle. There is a lot of crap supposed stainless steel that actually will corrode. There is also Stainless Steel which simply by it's metallurgy or chemical makeup will corrode to the point at which a layer of corrosion covers the entire part. If this corrosion is disturbed, like if you scraped it with a screw driver, the bare stainless steel will then corrode again in a fashion similar to "self sealing or self healing". Titanium alloys exhibit the very same phenomena.

WEIRD FACTOID-Titanium metal is found at concentrations of 80 parts per million (80ppm) in the Nettles plant.


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.
Mark Lelchook / Owner Performance Welding Racing Headers


Some of the OEM exhaust manifolds like those used on teh 1997 LT4 Firehawk and LT4 SS Camaro, and some of the double walled LS1 Vette and GEN 4 LS9(S/C 6.2/376cid) and LS7 7.0(427cid) exhaust manifolds are made of stainless steel. Another example of a quality stainless exhaust manifold are the turbo exhaust manifolds found on the 1987-1991 RPO B2K twin turbo Callaway Corvettes.
These examples do use a heavier gauge of metal than any eftermarket tubular exhaust manifold(header) does. The OEM's do have a very focussed need to keep as much exhaust heat actually staying inside the exhaust gasses rather than being transg=ferred elsewhere simply to get those catalytic converters up to temp as quickly as possible.
Getting cats up to temp. ASAP is illustrated very well in the 2014 direct injected GEN 5 LT1 Vette engine and L83 5.3 and L86 6.2L truck engines. These engines inject fuel in a conventional direct injection method as well as injecting a bolus of fuel much later into the injection phase, specifically for the late fuel bolus to remain at least partially uncombusted(?) within chamber specifically to partially burn within the exhaust manifold and headpipe thus increasing exhaust temps and catalytic converter temps. as quickly as possible.
Here is a picture of the GEN 5 Direct Injection Piston.
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/lt1piston_zps4b18f63e.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/lt1piston_zps4b18f63e.jpg.html)


Those "holes/spaces/slots" are there in part, to accomodate this "late injection" which is ued to heat the cats as quickly as posible. Those "holes/spaces/slots" "hide" the fuel air charge for the flame front that originates from the spark plug after it fires, then exhausts their contents out through the exhaust valve, head, manifold and headpipes leading to the cats.
The majority of the GM reported 10 million hours of computer CPU(Central Processing Unit) was spent on the combustion process, fluid/flows throughout the chamber and other subjects relating to the cylinder head, valvetrain and injection.
While the ECM is commanding this catalytic/engine warmup protocol, te eECM is also commanding the piston oil squirters to "shower" the bottoms of the pistons in engine oil. The piston oil squirters are only activated during this warmup phase as well as at when the engine is at WOT. Having the squirters activated during the entire duration the engine is running, introduces excessive oil windage thus reducing engine efficiency and increasing fuel usage.
GM did their homework on these GEN 5 engines. Most of the engine wear and most exhaust emmisions occur during the first seconds after an engine is is started. The "bolus" of fuel that is injected late in the compression phase and the piston squirters running concurrently help to manage both the high engine wear and high exhaust emissions that occur at and after engine start.
Pretty cool stuff. IMO

If I were to be using some sort of turbocharger after the exhaust header(such as a rear mount unit) I would avoid a coated header, no matter what material the header is. Reason being I wouldnt want a piece of coating to go through the hot side of the turbo.
In my personal experience with headers shows that there aren't too many header manufacturers that offer a coated stainless steel header, only mild steel headers are available with any sort of coating. The only stainless steel Hooker longtubes from Hooker has coatings as an option. Hooker has some new coatings:
Darkside Ceramic Coated (optional coating)
Titanium Ceramic Coated (optional coating)
Silver Ceramic Coated(this is their standard coating)

This is a ditty from the Hooker Headers site.
Installation Notes
Breaking in an engine with ceramic coated Headers (http://www.holley.com/index.asp?division=Hooker) WILL result in damage to the coating and will VOID all warranties. Ceramic coated Headers (http://www.holley.com/index.asp?division=Hooker) require several heat cycles to fully cure before they will withstand extreme heat. Hooker (http://www.holley.com/index.asp?division=Hooker) recommends using cast iron exhaust manifolds (http://www.holley.com/types/LS%20Cast%20Iron%20Exhaust%20Manifolds.asp) or old Headers (http://www.holley.com/index.asp?division=Hooker) to break in new engines to avoid coating damage. Please call Hooker (http://www.holley.com/index.asp?division=Hooker) tech service at 270-781-9741 for additional information regarding ceramic coated exhaust products. The use of header wraps can cause the header tubes to crack or rust due to excessive heat and moisture build-up. Hooker (http://www.holley.com/index.asp?division=Hooker) does not recommend the use of header wraps as this will void the warranty.

To determine if coatings actually help to keep underhood temps down, you woudl have to have a couple heat transducers located under the hood and do some temperature logging. Then swap the headers and repeat the testing procedure.

I think that the process in which most people decide on what header to buy is based off of a lot of hearsay and speculation. Most often time it works though, simply because most stock exhaust manifold.catalytic converter and headpipe design can be improved upon quite easily, esp. with older vehicles. Most modern exhaust manifolds, cats and exhaust system do a very good job and doing a exhaust manifold to tailpipe system upgrade nets less power/torque gains than it did years ago.