I recently went through another set of weird filter setups for it to ultimately last a year so I'm in the market for filter set up.
I used to run something similar to this:
with an K&N pre charger and some other filter wrap around that, needless to say the rotary is hungry and it literally chewed up and discolored the filter "element" as well as one of the pre-chargers/K&N filter wrap
but here is the gist:
13b Rx7 FC rallycross and ice racing car
mikuni side draft carb
mud/dust/dirt/sand/ice etc
now I'm looking at these foam ones due to the environment and run new individual filter prechargers on it.
Anyone have any experience on these foam ones? will this filter too little for my application? Either way its an uphill battle...
I'm running the first filters you've posted. They pop-off when there is a backfire (lost one due to that after it landed on the header.) I've safety wired them in place so that they don't go AWOL due to a backfire (tuning ITB's is a PITA, BTW)
The Foam filters like to catch on fire and melt if there is a backfire.
I would look at a metal housing solution with an oiled filter (less likely to catch fire, lasts longer)
Otherwise, don't bother with the foam and zip tie/clamp some old socks over the openings and change them after each event. The effect is the same.
I never had an issue with it physically popping off, I'll snag a photo of what it looks like now and I did to finish the last rallyX...
Those little screens do nothing but block air flow.
Foam filters do flame BTDT but if i had to pick a filter I'd run those over the screens.
You'd be better off to bend up a Shoe box to take a rectanglar filter say one from a 96 ford f150. Use JB weld or Alex calk to seal the box to the velocity stack mid point and tie wrap the filter in.
I've used this ford filter on several home spun boxes and K&N sell a fabric one if you what a cleanable one.
In reply to 44Dwarf:
I would have to 'relocate' my oil filler neck to do that, or cut it and re-weld super short, but I don't have a welder nor do I know how lol.
I've used those foam filters on motorcycles with good luck, nothing in the dusty conditions of rallycross though. They are made for dirtbikes so they much do something for the dust/dirt.
Could you use the small K&N cone filters for motorcycles?
Sooo... those screens are a bad idea? I was wanting those for my car, because my foam socks are WAAAYYYY too tall to clear the hood.
They are when you are driving in these conditions:
In reply to 92CelicaHalfTrac:
You must have an IDF then I take it rather than a DCOE style.
fidelity101 wrote:
In reply to 92CelicaHalfTrac:
You must have an IDF then I take it rather than a DCOE style.
He is running these on a KLZE Escort:
FWIW i still have the screens in that picture... but the mesh seems pretty damn minimal, not much filtering going on.
I doubt you would get much filtering with anything that would clear the hood other than a panel filter adapted to the throttle bodies somehow.
But if you are doing that you might as well box them in and add boost. 
EvanB wrote:
I doubt you would get much filtering with anything that would clear the hood other than a panel filter adapted to the throttle bodies somehow.
But if you are doing that you might as well box them in and add boost.
Well, i'm not asking to clear the hood entirely.... i just don't want these stupid socks sticking 6" out of the hood.
You may be able to separate the foam from the flange, cut it down, and re-glue it to the flange to get shorter socks. Not sure if that would work but they are cheap enough you could give it a try.
They make them as short as 3", you could also get some of these and cut them down and clamp them on:
fidelity101 wrote:
In reply to 44Dwarf:
I would have to 'relocate' my oil filler neck to do that, or cut it and re-weld super short, but I don't have a welder nor do I know how lol.
Is there a reason one of these won't work?
http://www.alamomotorsports.com/weber/air_filters.html
In reply to EvanB:
the air horns tend to protrude from out of the filter and that metal plate is within a .5" of the air horn inlets...
and I just pulled the trigger on those foam filter covers because I also ordered longer air horns :) Gonna pick up some K&N snowchargers or filter wraps for the foam just incase.
What you want is an actual airbox, not separate filters. I found on the first ITB engine that I did that filters on each individual throttle creates much restriction.
I wonder if you could adapt the dual-snorkel setup from an older Ford truck somehow.
PS - You'll be happy to know that my new engine is in and it started and ran on its own today. The old engine had a 100rpm "lump" at idle, the new one is 400rpm. Every brap swings it from 1200 to 1600, then the compression pulls it down to 1200 again. And tapping the throttle zings it up like a dirtbike. Of course, I'm using FOUR 42mm throttles now
As far as the oil fill neck goes, you can just yank the whole thing out and get a generic 1.5" push-in style and it will fit the engine. I used one of those like that for years.
Knurled wrote:
What you want is an actual airbox, not separate filters. I found on the first ITB engine that I did that filters on each individual throttle creates much restriction.
I wonder if you could adapt the dual-snorkel setup from an older Ford truck somehow.
PS - You'll be happy to know that my new engine is in and it started and ran on its own today. The old engine had a 100rpm "lump" at idle, the new one is 400rpm. Every brap swings it from 1200 to 1600, then the compression pulls it down to 1200 again. And tapping the throttle zings it up like a dirtbike. Of course, I'm using FOUR 42mm throttles now
As far as the oil fill neck goes, you can just yank the whole thing out and get a generic 1.5" push-in style and it will fit the engine. I used one of those like that for years.
yeah probably, but this was too tempting!
I will be running individual filter wraps for each of the foam filters shown.
I also have to shorten my oil filler neck assembly.
