This may sound stupid, but I was wondering if people actually drive around w/o an air filter? I see lots of pictures in magazines, etc. and alot of them dont have air filters. Is this just for picture purposes? My winter project includes going single turbo and even though this car is only driven on nice days I cant imagine not running an air filter, or can I?

 

You should definitely have one. Unfiltered air will eventually take a toll on the housing and seals.

Somewhere in the search results is a thread with pictures of what unfiltered air does to the housings over time.

 

I don't have one because I can't fit one. Driving with out an air filter is probably one of the worst things over time that will wear on an engine. Think of your self driving through a construction zone and sucking up all of the kicked up dirt. Im going to have a custom built manifold this winter just so I can run an air filter. I guess some people think an air filter will cause a great loss of power but the proper sized filter might cost you 2-5 whp.

 

I ran without one for a bit as it came from Japan without one and without room for a good sized one, didnt do any harm in the few 1000 miles I did, even one one REALLY dusty drift day that I was convinced was going to kill it.
BUT its a bad idea and soon as I could I moved things around to fit a BIG and I mean big, K+N cone, and its been great since.

Reason people think they restrict power is so many people (esp cars in Japan or fitted with Jap made induction kits) fit filters WAY too small for the turbo.
Ive seen RR testing in the flesh on a 600bhp car with the largest of the Blitz cone filter they do, which is way bigger than a lot of the crappy things people run, and there was a significant vacumn with it fitted (hence why so many run metal filter-turbo pipe), and with a silicone hose fitted it was enough to suck it shut on full boost. With a decent sized (K+N or RamAir, i forget now) filter charge temps went down, power went up to the same level as no filter, and it didnt suck the silicone hose shut, of course.

 

https://www.rx7club.com/single-turbo-rx-7s-23/part-k-n-shorty-4-inch-air-filter-722123/

 

There are always very fine stainless mess that people can run if they have no other options. My local metal supplier has a variety in stock. Just an idea.

=Benjamin

 

People crack jokes at me having a filter on my big turbo rx7 all the time.

But seriously, who wants a june bug to kill their investment?