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Ceramic Coating Headers

JoeVF2

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i posted about it not long ago on here, im glad i never bothered getting it done as the engine bay is no hotter then it was with factory cast manifolds in my opinion, the guy who installed em said unless im doing a standstill burnout for minutes on end there no need for it. i pulled the rubbers out of the vents in the bonnet to everythings sweet.
 

VinnieLS3

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Thanks guys..

Think I'll get it done but probably just get the outside done and not bother with the inside of the headers... it's only a street car so shouldn't matter too much.
 

monty_vfssv

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I have ordered dpe headers with ceramic coat, not sure if they are coated inside or not. Only got it because of how close the ignition leads are to the headers and ive heard its pretty good stuff. Apparently you get a few extra hp as well which is an added bonus.
 

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You definitely don’t want to coat the inside of your headers from a performance perspective. Only the outside.
 

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You definitely don’t want to coat the inside of your headers from a performance perspective. Only the outside.

Can you expand on that thought?
 

monstar

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Can you expand on that thought?
Sure, ideally the exhaust gases (from a fluid dynamic perspective) should be as hot as possible in this application. Hot gas will flow faster and react predictably to the design features of the header and collector.
Specifically exhaust gas ecape velocity is promoted by heat, decreased with cooling. Similarly greater flow is dependent on exhaust temperature:
9ABF2498-54AA-4571-96EF-15755FD86FB8.jpeg
 

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Yep I fully understand the exhaust heat theory, I was enquiring why not to coat the inside of the headers.
 

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Coating the outside of the headers contains more heat inside.
Coating inside means less heat is accumulated immediately after the head, where it is expected by the header design, instead the primary area is cooler and without heat entropy to the pipe as expected so energy travels further downstream and faster than otherwise predicted in design.
I used outer coating and full coating to this effect when fabricating the prototype CrossBones 180° headers, to balance entropy from unequal pipe length from one bank to the other.
 

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FWIW I don’t think many (as in hardly any) 4-1 exhaust headers are tuned to the fuel, CFM, EGT or peak RPM of the engine in any case :cool:
From what I’ve learned the dpe headers are designed for high peak horsepower being tuned for 6.2 with hot (high 20’s near .600 lift) cam on 98.
Coating the inside would have the effect of moving the tuned merge of same pipes several inches to the rear, which would lower the header’s tuned RPM peak, also requiring revised collector dimensions.
Good news it would make the dpe cats that are (non-functionally) way back to work better.
 

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That is certainly an interesting point of view. So what you are saying is that with a fully coated header you would want to increase the primary pipe length to allow for the increased exhaust velocity?

edit:lol, you beat me to it...
 
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