Heat Shielding

[Bartman]

I was hoping there may be some advice on thermal shielding from those in the know. Before I took my car off the road for the re-build I did have a chance to drive it some and I noted the almost insane amount of heat radiating off the transmission tunnel attempting to turn my calf to medium rare. So, before I install the new and much more powerful engine (even more heat) I am thinking about some sort of thermal insulation in there, the tunnel is not closed so there is airflow there but it is still ridiculously hot.

 

I was looking at the pictures of the latest build on the build thread and noticed that Caterham now come with some thermal insulation in the tunnel

 

So I have two questions :-

1. Any recommendations for the self adhesive foil type insulation that I could apply to the bulkhead and tunnel walls (brand & effectiveness) ?

2. What about wrapping the headers?

 

I know the heat has to go somewhere so has anyone come up with other ideas to keep the tunnel cool whilst not retaining all that heat under the hood.

 

As usual thanks in advance for any thoughts.

 

Bart.

[Pokey]

I didn't notice any branding on the insulation from the factory, but it looks like typical Reflectix style foil.  I've personally not used or even seen a self-adhesive type, but have used spray-on contact adhesives to apply without issue.  A roll of decent aluminum foil tape is handy for repairing tears.

[CarlB]

I have used this: Amazon.com: Thermo-Tec 13575 Adhesive Backed Aluminized Heat Barrier, 12" x 24" : Automotive - I wouldn't say it is great. It does some good. I am aware of some gold reflective insulation that is used on high end race cars, but do not have any experience with it. I saw your car and love the cam cover on your new engine. 

[NSXguy]

I've used the adhesive style reflective thermal insulating material on my xflow seven and it made a huge improvement. I installed this just around the footwell and partially into the trans tunnel areas that were accessible since the engine and trans were still in the car. Now that i have everything apart for a refresh, i anticipate doing something similar (or more robust if i can find) before everything goes back in. I agree it can be absolutely brutal if driving for long periods without some insulation in place. I believe what i used was purchased from Amazon. 

[coffee break]

Several years ago, I took the opportunity to apply some reflective insulating material to the firewall and as far as I could get down the tranny tunnel. I also wrapped the exhaust header. I got the header wrap from Summit Racing, the insulation may have come from Pagasus. Needless to say, it was much easier to do with the engine and transmission out.

It is highly recommended.

[Renottse]

@Bartman, I went with a combination of heat shield products and got a significant reduction of in cabin / tunnel temperatures.  
 

I didn’t have the engine and gearbox box out so went with,

https://www.heatshieldproducts.com/floorboard-heat-shield

to reduce the heat from the tunnel. I went with two 24 x 36 with magnets, cut them to fit the profile of the tunnel and added snaps for fastening. 
 

When the engine/transmission come out in the future I’ll most likely do the tunnel in,

https://www.heatshieldproducts.com/hp-sticky-shield

 

They have a lot of solutions for headers and cater for the fully wrap it / don’t fully wrap it arguments.

e.g,
https://www.heatshieldproducts.com/lava-header-armor.

Or,

https://www.heatshieldproducts.com/lava-exhaust-wrap

 

I don’t have my headers wrapped but do have a catalytic converter in the engine bay that is wrapped and that does help keep the passenger footwell temperature lower. 
 

I used their exhaust shield and wrap on the external exhaust and muffler to reduce radiant heat to the passenger an reduce the chance of my wife burning her leg a second time. 

 

 

[IamScotticus]

I know this as well.  I carpeted my tunnel which helps, but still still very hot.

I have been thinking of covering the foot wells with sheets of aluminum stood off about a quarter inch for airflow. This should block the radiant heat.

Opinions?

[Croc]

 

All of these solutions are using shielding.  Also consider adding a vent that - once you are moving - pushes air through the engine bay and transmission tunnel reducing temps.  While I have shielding, I was still burning my elbow on chassis tubes as the hot air was stagnating inside the transmission tunnel even when driving at speed.  The forced air venting was the solution that finally worked for me.    

 

I used a carbon fiber snorkel in front of the under-bonnet sausage filter to get a cold air intake, reduce my under bonnet temps, reduce my intake temps (by 20degF) plus make air consistently flow front to back.  In the photo, its the black bulge on the side of the bonnet.  

 

 

[IamScotticus]

This leads to the concept of wrapping the primaries, or header wrapping. 

I have always read this practice will or may "shorten header life".

Can someone educate me on what is happening when they fail, or if this actually happens at all?

Edited February 1, 2022 by IamScotticus

[Bartman]

Thanks to everyone for the advice. I am sold on the insulation/reflective materials and have ordered from Pegasus a few different ones to test out for usability and adhesion. Still on the fence about the header wrapping. Thanks @Carlb for the comment on the Cam cover, it came from Raceline and I think it looks the business  

 

 

[7Westfield]

My experience with header wrap............

When I bought my pre-lit the first time, it was hot in the footwell, so I wrapped the header. When I bought it back 5 years ago, the wrap was still there. 25 years

It was getting crunchy, so I peeled it off in order to measure for building a new one, since primaries are very small.

SUPRISE   it's as good as new, except that it's now got a green hue to it. It's chrome plated, must have been a reaction between wrap and plating

I always heard wrapping would cause a header to rust out, but not this one. Maybe the plating saved it, maybe not. It's also pretty thick gauge tube.

I'll wrap the new one as well, really helps with foot temps, and paint with Eastwood paint

[kayentaskier]

I have a standard 420R; as indicated above, the new kits come with heat shielding from the factory. In addition, Josh Robbins and I decided to have the headers and collectors Cerakote coated to help reduce temperatures. I can honestly say that I don't have any issues with heat in the cockpit. With that said, I don't track the car and don't usually drive the car when it above about 85 degrees, so you mileage may vary.

Jim

[IamScotticus]

On 2/1/2022 at 8:33 AM, 7Westfield said:

 and paint with Eastwood paint

Im really considering doing a DIY with grey Eastwood high temp.  The whole thing.  SS against bare aluminum is too shiny. 

Edited February 2, 2022 by IamScotticus

[papak]

I feel quite fortunate, having a Birkin, to not have experienced these heat issues. My transmission tunnel is incredibly tight as well but I have NO heat issues. In fact, I wear shorts all year round out here in SoCal when driving the car. Just visually, I have a similar array of louvers to Croc’s car. There is a layer of reflective insulating material in the tunnel resulting in about ⅛” clearance all around. 
 

[sltous]

A few months back I added footwell insulation to the inside of the pedal box cover.  Admittedly, it has not yet gotten hot but I have been pleasantly surprised that so far I have not had to stop and get out to let my feet cool down.

 

If you are already thinking about fitting insulation I would recommend considering this area as well as it is just a thin aluminum wall between the hot engine compartment and the driver's footwell.

[linenoise]

sltous: which product did you go with?

[Wayne Stambaugh]

I know I’m way late on this topic but I have used a couple of things in my auto restoration work that really help out with heat. The first thing is a product called Lizard Skin. This product is a thick gray/black material that you spray on with a purpose build spray gun. If I recall the gun was about $60 and I don’t recall how much the product is. It can be purchased in a number of places online, for example Summit Racing and JEGS. I have an MGA coupe that tends to get pretty hot in the summer time here in alabama and I used Lizard Skin on the floorboards, the tunnel and the firewall and it really helped.

 

The other product is White Lightening and it is a product of Swain Tech Coatings in Scottsville New York. This is a true ceramic coating for your headers and exhaust system. You have to send you parts to them for coating but it’s the real deal. There is also a company called Jet Hot that coats exhausts but they don’t hold a candle to Swain Tech. If you want a pretty exhaust system don’t call Swain Tech. There focus is on keeping the heat in the pipes. This helps increase the speed of the exhaust flow out the pipes and also reduces the heat coming off the outside of the exhaust. This is not spray can magic, it’s a realatively expensive product but it does what they say it does. If you just did your headers I think you would surely feel some heat reduction. Beware there is plenty of debate about coating like this but I have experienced not issues with it. They did a great job and although I was warned that it’s not pretty, I was very please with the look when I got the parts back. Hope this helps.