heat management

[Rian_Colorado]

Since it's 10 degrees outside, and snow covers the ground - I'm obviously thinking about how to keep things cool under the hood of my Mk4.

I'll be running a 427, with Gas'n headers and pipes. I'm sure there are many here running similar setups, and I'm wondering just how significant the heat output is? I'm sure it's an issue, as there are many threads referencing it, and even some with elaborate setups trying to cool the footboxes.

In my mind, the easiest way to cool the cabin area, is not to let heat in to begin with. I'm planning on doing the entire inside of the footboxes and firewall with Cool-it as many do but what else is big hitter in controlling heat? Is it worth the work to do it? Spending many hours and $1000 to drop the temps 4 degrees is NOT the goal!

I'm planning to coat the headers. (Jet-hot? Cerakote?)
I've also thinking about doing the outside of the footboxes in DEI reflect-a-gold.
Possibly wrap the headers? (I've also seen companies like Funk Motorsports that make custom sized blanket/covers for manifolds.)

My intentions with the car are more track/autocross than street driving, but I'm SURE I'll end up doing both, so trying to make it as comfortable as possible. Won't be adding heat or AC. None of this really adds that much weight, but sure is a LOT easier to do BEFORE the motor goes in!

Thoughts or experiences?

RR

[egchewy79]

Biggest heat source will be from the gap between the body and the footbox. I drove in gelcoat for 2 yrs and it would feel like a hairdryer blowing on my leg before this area was sealed for good using AC foam by my painter. Many will put a cold air blower bringing fresh air in, but I don't find that my feet get hot while driving. Most of the heat is coming from the burning ball of gas in the sky.

[Bill Elliott]

Being in Texas I have never had an issue with the heat from the engine compartment. 90-100 degree temps only issue is the sun. I have the mat on entire cockpit and the foam between the fender and footbox, that was plenty to supress the heat . Just as chewy said.

[John4337]

I used second skin stuff on my build, and they stopped it well, but I'd recommend spending a lot of time on leaks thru the foot boxes or firewall, at the seams or where wires pass thru. Even a small one can feel like a blowtorch at speed. Good luck.

John

[CraigS]

Do what ever you can on the inside but be SURE to seal off all air from the engine headers area. I know the gold reflector stuff is good but dang your car will look like a lunar lander. I'd skip that and, only if needed after a year driving it, I'd put a layer of stainless sheet spaced off the footbox 3/8" on the engine side of the aluminum.

[Mike.Bray]

I installed Thermo-Tec like most, being careful that there weren't any gaps. And did the AC foam between the body and the footboxes. When the car was complete we turned the lights out in the garage and shined a light from the engine side looking for light on the inside of the footboxes. Found a couple of very small holes that we sealed with silicone.

I started with polished stainless headers which radiated a lot of heat and quickly turned ugly so I had them ceramic coated which made a noticeable difference in temperature. If you have stainless headers I would avoid wrapping them as it can cause cracking.

The gold reflective foil makes a difference.

https://www.imagecoast.com/images/MichaelBray1/20221127124557mediumrotated.jpg

I can tell you my wife has ridden with me many miles wearing flip flops and no complaints about heat. Even though we installed footbox cooling fans we really never use them.