Does car engine air filter surface area make much difference?

09 Nov 2015

So straight to the point: does increasing your air filter surface area make a difference to the airflow? And if it does, which way?

I’m not a genius in physics but maybe someone of you is ;D
So I have thought it a couple of ways:

A) the flow resistance is doubled because of the airflow being guided through 2 different channels with same filters > same force is required to pass the filter from half of the air flow

B) flow resistance is reduced noticeably because of air having more passage in the filter because of the extra surface area

C) the extra surface area makes no difference with clean filters

BUT how does it really go?
Oh and this not a “real problem”, it just came across my mind the other day. Thx for your time ^^

Comments

it depends, i think
in my ‘94 mx5 the limiting factor is the air mass meter (not sure if that’s the correct name for it) that has a small diameter.

I think it’s called an ‘air flow meter’

Yes more surface area is better, you can think of an air filter as a fine strainer (because it is one), the more surface area you have, the less restrictive it will be as there are more openings for air to pass through. Also when the filter gets clogged with debris (which will occur, even after a short timespan) there are going to be more unclogged openings in a filter with a larger surface area due to a greater number of openings. However the arrangements you have shown can be undesirable from a fluid dynamics and cost standpoint. With two separate intake pipes the pressure inside the pipe would be decreased due to the increase in air velocity and this would affect combustion. The cost of fabricating an intake system would also be increased and there would need to be more components to make the system work. Most aftermarket systems use conical air filters which are engineered to improve performance. But air filters aren’t the only source of restriction, the intake valves in an engine can also restrict airflow and limit an engines performance potential.