Air filters

johnsy

johnsy

Active Member
Anyone know what the least restrictive filter is on the market?

currently have an A-pexi filter fitted which was on the car when i bought it, im in the process of fitting a bigger turbo and heading for hopefully 400bhp and would like to help it breath as much as possible

Thanks Dan
 
Spikey

Spikey

New Member
You Serious?
How about you ask on the Air filter forum, they can help you. :doh:

IF you want filtration then you best sticking with what u got. otherwise use a Blitz metal mesh one.
 
PobodY

PobodY

Moderators
Staff member
The least restrictive is chicken wire surely. - That might not be the smartest thing to use though unless you don't give a shite about filtration.

The balance is probably to go with something that has good filtration and a large size so that the volume of air it can filter is still really high. I like the M's K&N.
 
johnsy

johnsy

Active Member
Spikey said:
You Serious?
How about you ask on the Air filter forum, they can help you. :doh:

IF you want filtration then you best sticking with what u got. otherwise use a Blitz metal mesh one.
Click to expand...
Spikey said:
You Serious?
How about you ask on the Air filter forum, they can help you. :doh:

IF you want filtration then you best sticking with what u got. otherwise use a Blitz metal mesh one.
Click to expand...
you keep up the insults you'll find out how serious i am!,

Im more interested in people opinions who actually know what there talking about! the likes that are running 400+bhp, by all accounts the A-pexi filter is quite restrictive and the last thing i want is my turbo struggling to spool because of a restrictive filter.

What is it these days with no-it all muppets shooting peoples questions ,you clearly know no more about air filters than i do so why comment, An air filter is just as important as a free flowing exhaust,


like iv stated maybe redreading or madforit could let me know what air filter they have fitted ? please
 
johnsy

johnsy

Active Member
PobodY said:
The least restrictive is chicken wire surely. - That might not be the smartest thing to use though unless you don't give a shite about filtration.

The balance is probably to go with something that has good filtration and a large size so that the volume of air it can filter is still really high. I like the M's K&N.
Click to expand...
I had the answer im looking for but iv missplaced it, one of the magazines did a test recently on induction kits/filters and the K&N didnt bode to well, im after the least restrictive air filter i can get my hands on, and no i dont want my turbo shitting itself and destroying my engine so chicken mesh is out of the question
 
Trondelond

Trondelond

Active Member
The less restrictive the filter is, the more dirt you'll suck into the turbo. So I guess it's a balance thing. However, I think the Apexi is more than enough for 400 bhp.
 
stumo

stumo

Active Member
one of the magazines did a test recently on induction kits/filters and the K&N didnt bode to well, im after the least restrictive air filter i can get my hands on
Click to expand...

Forget what the magazines spout, get the biggest meanest muthafecker of a K+n you can get, that way you get good filtration and there will be very little restriction because of the surface area.

Without good filtration your engine will be sucking in dirt and your rings and valve seats won't last long.


 
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PobodY

PobodY

Moderators
Staff member
There are a couple of articles that crop-up like that. - They either focus on the biggest HP gain (and ignore filtration), or best filtration (and ignore if that flows worse).

I don't know about A'pexi, but K&N say they their filter gets better with use; the dirt it catches clogs the pores and improves the filtration.

I'm with stumo on this one:
 
campbellju

campbellju

Moderators
Staff member
Stu beat me to the answer. Just make sure it's big enough to not be a restriction and does the job of an air filter that is giving you clean air to not mess up your MAF. Buy a universal filter and not a kit as you can usually upsize for less money.

This might be the fabled test you're looking for:

http://www.mkiv.com/techarticles/filters_test/2/index.html

a 1hp difference between the best and the worst in RR terms is negligible and lost in the margin of error at 400hp.

For an NA car, induction length of the kit rather than the filter itself does have an effect on the response and power curve of an engine.

Below is a light hearted experiment that is spot on and always makes me laugh.

http://www.mgcars.org.uk/peterburgess/flugelhorn.html

The other consideration is location, Stu's location at the front of the engine bay so you can get cold air in. This is better than the original position hidden behind the battery etc (Sorry George).

Jim
 
johnsy

johnsy

Active Member
I thankyou very much, bigger is better it seems , i guess thats speaks for itself really a larger surface area and all that ,
 
P

Perrin21

Member
don't forget to shield whatever you get from engine bay heat. I still believe there is a case for retaining the original air box with a high flow air filter and maybe improve the size and routing of the tube that takes the air to it. Just a thought.
 
johnsy

johnsy

Active Member
I have a headlight duct and the filter sits behind it, plus a cold air feed pipe from the front brake duct channels cold air up from behind,

i was thinking about making a very crude and free flowing filter just for trackdays and the odd trip to the strip, I have a way of measuring how effective the filtration is by way of a magnahelix
 
Spikey

Spikey

New Member
Its not just the Air filter that restricts the air also bends slow air down so the the more Direct the better really.
 
campbellju

campbellju

Moderators
Staff member
Could do but your off boost torque might suffer. Need your turbo top mounted too or your air intake will be between the radiator and the hot engine. Not cool..... if you get what I mean ;-)
 
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