Exhaust manifold wraps

[Frank Lee]

Maybe reinstalling the heat shield would do it?

[California98Civic]

Originally Posted by Frank Lee

Maybe reinstalling the heat shield would do it?

Maybe, but maybe not. The heat shield was for a stock set up, but I have grill blocking. The heat conditions I reported above were with the heat shield installed. I am anticipating the return of those conditions when the hot months return. The wrap or paint would be preventative of future failures, though who knows maybe the unicorns will give me an MPG push too. This car is my daily driver, and I need reliability. Even though I have a lifetime warranty on my dizzy, I want to reduce the likelihood of failures that keep "black and green" off the road (or leave me sitting on it waiting for AAA).

[ConnClark]

Originally Posted by California98Civic

But hey, I just realized I posted in the unicorn corral because of the FE and HP claims associated with the wraps. Maybe those claims are unicorn material, but the heat reduction seems worth while, no?

Its well proven and measurable on a dyno that insulating an exhaust pipe can improve power through reduction of back pressure. And a reduction in back pressure will translate to a real world savings in fuel. Why would you list it here?

If your going to do a grill block of any kind you will want to reduce under hood temps as much as possible. The following article is a good read.
http://www.engr.iupui.edu/me/courses...stManifold.pdf

PS. don't assume painting a heat shield black is going to make it work better. It may make it work worse.

[California98Civic]

Originally Posted by ConnClark

Its well proven and measurable on a dyno that insulating an exhaust pipe can improve power through reduction of back pressure. And a reduction in back pressure will translate to a real world savings in fuel. Why would you list it here?

Because the implied claims I saw for great fuel economy on the Thermo-Tec box in the Autozone seemed misleading. Unicorns often exaggerate plausible results for marketing advantage, like a horse with a horn, or that can sprout wings and fly! But maybe this thread should be moved by moderators. I'd support that.

Originally Posted by ConnClark

If your going to do a grill block of any kind you will want to reduce under hood temps as much as possible.

Agreed. And so, the questions. Thanks.

Originally Posted by ConnClark

PS. don't assume painting a heat shield black is going to make it work better. It may make it work worse.

I didn't. It's about appearance. Only top side is painted. Why worse?

And thanks for the link. The civic has a cover, but I would bet it could be improved.

[ConnClark]

Originally Posted by California98Civic

I didn't. It's about appearance. Only top side is painted. Why worse?
.

Black body emissivity is a measurement of how well something absorbs or emits light radiation. If you have a heat shield between something hot and something you want cool and paint it black, it will absorb the IR heat from the hot side and radiate it on the cold side thus heating what your trying to keep cool.

Emissivity - Wikipedia, the free encyclopedia

here is a table of emissivity for different surfaces.

http://www.monarchserver.com/TableofEmissivity.pdf

A bare aluminum heat shield is better than something that is painted. Ideally you would want a heat shield coated in polished silver.

[California98Civic]

Ugh. I consulted the materials you linked. Thanks. Clearly painting my shield was a mistake as far as the emissivity of the shield goes. But IAT temps are down from when the heat shield was off. So I have to think that an aluminum heat shield painted flat black on the side opposite from heat source (exhaust manifold) is significantly better than none at all. But do you know a good layman's way to estimate the difference between my heatshield painted versus unpainted? If it is significant, I can consider removing the paint, obviously.

[Daox]

I don't think you'll see that much of a difference.

[ConnClark]

The heat radiated from the black side of the heat shield will be radiated roughly at a normal to the plane of the surface(perpendicular to the plane). The radiated heat will heat up objects that are in this direction. If you don't have objects in this direction that you want to keep cool don't worry about it. If this is the case and your trying to keep air that flows over the heat shield colder you may have done the right thing. If not and you want to keep it for looks just polish up the other side.

calculations like this are very very complex. Things are best solved by experimentation in this case.

[ConnClark]

As an after thought I did some searching.

For about $25, you could get one of these and put it over your heat shield. It would then add some insulation as well.


JEGS Performance Products 32040 JEGS Heat Shield Panel

[ron]

are you talking about the heat shield just above the exhaust? if so it may be better to call it a heat absorber / radiator, it stalls the heat to the hood(no paint blister) and a shield so we dont touch the really hot exhaust and ask whats that? dang thats hot! The same heat is generated with or without it