Air Filter Theory

[KiwiTT]

Explained ...

[bradc]

lol, where did you pull that from?

[KiwiTT]

another forum.

[Turbo_Steve]

LOL! So true.
And all people really need to do is measure the pressure differential.
When you start seeing a large differential across the panel filter, you know you've exceeded it's capabilities, and it's time to change. Used to do it with a pair of taps into the airbox, a couple of non-return valves (£2.99 from aquarium shop) a tee-piece (free with valves) and a boost gauge. Even started measuring pressure between the mouth of the inlet and the "back" of the airbox. Found the "snorkus" was a massive restriction, even with marginal boost increases.

[djb160]

I was reading on on site some dude had added a twin cone filter down behind the bar for some cold air, but having read about something called hydrolock he thought he'd precautions and install a hydrolock filter up in the engine bay where sure it'd be sucking in warm/hot air if it was opened but that was seen as a better alternative to starving the engine of air. The interesting thing was that he found that under any sort of load the valve filter was opening and sucking in hot air. After testing on a nice dry day they deduced that the cone filter just wasn't in any way up to the task of providing enough air.

Not sure what they did after that because I accidentally closed my browser and couldn't find that page again. I just wonder if this sort of thing is true of most cars or not, have to be suspicious given the twin intakes on GTRs, etc.

[Turbo_Steve]

Not necessarily the filter, though....depends on the bends in his pipework, pipework diameter etc etc etc etc
Pressure drop vs flow rate.