Now we all know that the BFI is one of the most efficient forms of intake.

The stock airbox is cut open, the restrictive snorkel is removed and the airbox blocked off.

My question is, is it Okay to use packing foam to block the airbox from the hot engine bay? This packing foam is the soft/flufffy squishy one that comes in massive sheets that are a few cm thick (The type that is about 5cm thick but if you squeeze it it can become 3cm) Sort of like the ones you find when you open a motherboard case - like the grey ones here
http://www.foamexpress1.com/Packaging_Foam.php

I was talking to the Clark Rubber guy and he said that the foam would deteriorate due to the fumes in the engine. Also, my biggest concern is: Will this foam expand under the hot conditions of a engine environment? I know that some forms of foam will expand under heat. Or will it get so hot as to cause a fire?

 

I wouldn't feel safe using that foam. If I were you, I would get some ABS plastic and shape it into the shape I need. Or go to home depot, buy some Acrylic or Polycarbonate plastic and cut out your own custom piece.

Keep in mind that Polycarbonate is, I believe, the strongest and most heat resistant plastic. Although it is a little bit harder to work with. I used polycarbonate for my BFI mod.

Good luck

 

Polyethylene Closed Cell Foam is what you need. any type of closed cell foam really. go to your local camping store like Dicks or whatever and get it. its the foam used when sleeping on the ground to block out heat and cold because its closed cell.