Temperatures in the engine bay were very hot during the summer so I decided to construct some sort of heat shield for the air filter to sit behind and try to protect it from too much hot air. I thought I'd have a go at producing an air box like the ones the Fensport guys use on their cars. They use carbon fibre for theirs but that can work out expensive if you get it wrong.
I started out with a sheet of cardboard to get roughly the right shapes. Transferred that to thin ply and modifying as I went. The last version was made out of 0.5mm aluminium sheet (1.0m x 0.5m from B&Q). It's all pop riveted together at the corners to 20mm x 20mm ally angle and the lid is screwed down again to the angle. It may not be very pretty but it must be keeping out a lot of hot air.
The air filter hose had to be extended so that the filter could fit inside the air box. A Samco 45 degree bend and a short piece of 2.5" stainless steel tubing did the trick. All the holes in the ally sheet are edged with small bore tubing , split and held in place with clear silicon sealant.
Alongside the battery is a hole about 2.5" diameter. I decided to run a 3" flexible hose from the passenger side of the TTE WRC front bumper up to this hole to supply cold air from outside the car to the air box. Another bit of DIY
This time with the cover of a piece of 4" plastic trunking and a plastic rainwater downpipe converter from square to round and fixed together with epoxy resin. The front of the intake has black mesh (attached with clear silicon sealant) to stop leaves and the like getting drawn in and I drilled holes in the bottom of the square piece to allow excess water to drain away.
The top end of the hose has a piece of Samco hose clamped to it and fitted through the hole next to the battery - it's held in place with a jubilee clip above and below.