[The Nightman]

How do engine bay temperatures with uncoated catless headers compared to stock headers? I have read that thin-walled aftermarket headers radiate significantly more heat than cast iron manifolds, but I'm not sure if that is applicable to us since our stock headers do not appear to be cast.

Any input is appreciated!

[6ixSpd]

Not worth it. If anything, stock headers aren't coated and run even hotter as the cats are inside them. I installed my aftermarket without headers and there's zero detrimental to impact vs. stock.

But hey, if you want to blow a couple hundred bucks on the coating, go for it

[hassmaschine]

personally, I have done both uncoated and coated headers in the past, and I would never do another set of uncoated headers again.

OEM manifolds have a extra heat shielding that aftermarket headers do not, so it's not really comparable.

[W37V]

Originally Posted by freedomfries

How do engine bay temperatures with uncoated catless headers compared to stock headers? I have read that thin-walled aftermarket headers radiate significantly more heat than cast iron manifolds, but I'm not sure if that is applicable to us since our stock headers do not appear to be cast.

Any input is appreciated!

I have been running my AA headers "naked" for years now. They look the same as when I got them. I also never experienced any negative effects of such setup.

[Blueeyesredpanda]

What about wrapping the headers?

[hassmaschine]

wrap doesn't last very long, it absorbs moisture, oil, etc. which can lead to cracks in the headers. Wrap is fine for a race car but I would never use it on a street car.

[nsjames]

Originally Posted by hassmaschine

personally, I have done both uncoated and coated headers in the past, and I would never do another set of uncoated headers again.

OEM manifolds have a extra heat shielding that aftermarket headers do not, so it's not really comparable.

the oe manifold also has cats in it.

I can't imagine a catless manifold naked is going to be hotter than the shielded cats in the OE manifold.

a heatshield would be a simple thing to make anyhow.
freedomfries ain't scared to do some fab.

of course if ceramic coating was like another hundred bucks, I'd probably do it. Depends on the cost.

[Biginboca]

Knowing what I do now I would have coated my headers before install. I wasn’t aware of the better scavenging and extra power you get with the coating.

That said heat under the hood is not a real negative with uncoated. It’s more that you lose the full potential you could realize from the mod when you go uncoated.

[hassmaschine]

Originally Posted by nsjames

the oe manifold also has cats in it.

I can't imagine a catless manifold naked is going to be hotter than the shielded cats in the OE manifold.

a heatshield would be a simple thing to make anyhow.
freedomfries ain't scared to do some fab.

of course if ceramic coating was like another hundred bucks, I'd probably do it. Depends on the cost.

6cyl headers are usually pretty inexpensive. I think I paid $150 a few years ago for my E30.

[Blueeyesredpanda]

Originally Posted by hassmaschine

wrap doesn't last very long, it absorbs moisture, oil, etc. which can lead to cracks in the headers. Wrap is fine for a race car but I would never use it on a street car.

If the header is made out of stainless steel, how do moisture and oil lead to crack in headers?

[hassmaschine]

stainless steel can still rust. you're holding moisture constantly against the headers through many heating and cooling cycles. normally, water that gets on the pipes will just evaporate immediately.

as far as why it causes cracks, I'm not sure - but it is well known.

[rjahl]

Originally Posted by hassmaschine

stainless steel can still rust. you're holding moisture constantly against the headers through many heating and cooling cycles. normally, water that gets on the pipes will just evaporate immediately.

as far as why it causes cracks, I'm not sure - but it is well known.

Headers demand a lot from thin wall stainless tubing. Extreme heat and thermal stress is pretty high. The way these are bent and fabricated its not hard to see why they can crack especially when you consider how difficult it is to purchase good stainless steel.

We recently changed a good percentage of our fasteners to chrome plated 316 to fix the rust stain issues. Yes$$$ but we had no choice.

[nsjames]

header wrap is generally going to look like ass in a short time.

it's only for when you're gonna burn yourself on pipes.

and racecars.

[Noir]

+1 on the knowing what I do now...
Been debating getting my headers off the car and coated, or buying a used SS or AA header set and getting them coated and selling my old set for cheap. :

If you can get em coated, do it!