Thread: Air Box Size

Originally Posted by alanbettison

why do the air boxes have to be so big in depth?

The top bit of the air filter seems to be relativly short in depth

The reason why I am asking is that I want to make an air box for my V8, D2

Blown may up with LPG, which now seems to have settled down

A shorter depth air box will allow me to install a 2nd battery underneath

Hence the questiond as to why they need to be sooooooooo deep

thanks

Air boxes are designed using computational fluid dynamics (CFD) software to optimise flow and minimise pressure drop, within the given size constraints of the fitment. If it were smaller it would have been cheaper to produce, so I am sure it would have been made smaller if possible.

I put an early (87 EFI RR) cylinder air cleaner in the last D2 that came my way, now if it backfires he only has to replace the element, not the whole box. Performance doesn't seem to have suffered.
As to the depth, maybe its where a huge heap of sand can collect and be vacuumed out!

Originally Posted by alanbettison

why do the air boxes have to be so big in depth?

The top bit of the air filter seems to be relativly short in depth

The reason why I am asking is that I want to make an air box for my V8, D2

Blown may up with LPG, which now seems to have settled down

A shorter depth air box will allow me to install a 2nd battery underneath

Hence the questiond as to why they need to be sooooooooo deep

thanks

I did a bit of reading into the helmholtz effect a while back (interesting stuff look it up) and read some where that you basically need 120% of engine volume available (ltrs of air) in front of the throttle body. This apparently allows for a smoother laminar flow through the intake system and helps reduce negative pressure in the air box.


How true this is i dont know but as IR said, if car makers could cheap out and make it smaller you can bet you left nut they would!

My V8 Disco I bought second hand has LPG fitted and I noticed that the airbox is a cut down VL commodore box. It has the bottom cut off , the front side is angled and it is fitted with some l brackets and sealed with silicon onto the inner hump.
I'll post a pic when I get a chance. So definitely no computer mass volume flow blah blah design . seems to work ok.

They certainly didnt worry about depth on the D1

Pics as promised
VL commodore airbox