Yes that battery cover was missing when I bought the car, although the FD is the only car I've seen where the battery is vented and cooled by incoming air. Although its a non-issue because I'm running a marine bluetop optima battery, even if I weren't, I would have probably removed the battery box and sealed that hole anyways. I'd much rather have the incoming air cooling my intercooler rather than dividing that 1x10" slit to cool the intercooler, battery, as well as feed my intake (as with a stock setup).

that battery cooling hole is not as easy to seal as the intake hole on that shroud though, its a weird shape. I was originally going to fiberglass it but looking at my fiberglass kit, I just got way too lazy. bent slits of sheet metal and rivets was 100x easier to seal with.

like so



sealing the intake hole, the electrical tape is so I don't cut myself



and lastly extending the shroud a little bit because my koyorad causes it to sit higher than stock and it ends up not actually being in direct line of my frontal air flow



I like rivets

 

I agree thats why i took the M2 design and making my own, not very expensive to make. need some tube for the filters and a lid and its done. I like ur box tho very cost effective.

 

Report back from the track

previous peak IAT 87°C

new peak IAT 55°C

Could probably do a bit better if I sealed the lid better (there was quite a gap when I checked it out later), but 30°+ difference is not bad

overheating issues also 100% gone, track temps steady at 96°C, next thing to address will be oil temps (or at least putting in a gauge to find out what they are)