Air filters on a dirt track car???

[ZIGGY]

Overlooked that OP did not mention sealing grease. That's a given. Good paper filter for a night
is the expedient way, but you'll still pass the fine dust.

[JDR Performance]

We have them coming in all the time for service or rebuilds and we always ask what they're using if they're cleaner or of course dirtier than average. There are patterns.

[JDR Performance]

A Sure Seal or at least a gasket should be used between the air cleaner base and carburetor. Believe it or not, we've actually seen some 2bbl carburetors come in without the choke rod hole blocked off and yes they're caked with dirt.

[BLstangin]

Yes I’ve been using some grease gun grease on the top and bottom of the filter and we use a rubber from underneath a coil on an HEI on top of the air cleaner lid over the stud with a 1/4” washer on that to make sure it crushes down good and we have an adapter that goes on the air cleaner base and uses an oil filter gasket to create a seal on the carb. You have to actually work at it to get the base on the carb it’s such a snug fit, it’s a rochester 2g so it has the smaller opening and we are using a base with a smaller hole in it so no adapter is needed. That’s why I’m at a loss for where all the dirt is coming from unless it’s just the cheap air filter letting it all through.

[BLstangin]

We used to run just an oiled k&n and that motor lasted years but there was always some signs of dirt in the carb then to.

[pcnsd]

Most everyone considers filters based on a dirt trap and hold model. Over on the aircraft side, engine air particle separators are popular on turboshaft driven helicopters and that technology is beginning to find application on autos and UTVs. They still have associated flow losses, but if I read correctly not as bad as the capture filters. Some use a power source to run a savage air fan, others use the intake air flow and a gravity dump. It is not a bad concept for a prefilter.
The basic concept is shown below.

VortexFilter-color.jpg

EAPS.jpg

SB-2-IMG_4749.png

[ptuomov]

Most everyone considers filters based on a dirt trap and hold model. Over on the aircraft side, engine air particle separators are popular on turboshaft driven helicopters and that technology is beginning to find application on autos and UTVs. They still have associated flow losses, but if I read correctly not as bad as the capture filters. Some use a power source to run a savage air fan, others use the intake air flow and a gravity dump. It is not a bad concept for a prefilter.
The basic concept is shown below.
VortexFilter-color.jpg
EAPS.jpg
SB-2-IMG_4749.png

How about doing the same with a large micro twister plate?

[pamotorman]

I remember when dirt sprint cars just ran open unfiltered FI stacks

[Schurkey]

New/"clean" oiled-gauze (K&N style) filters are not as effective as dirty oiled-gauze filters. As dirt builds up on the filter, it wicks oil from the gauze, making it attract more dirt. The oiled-dirt build-up on the outside becomes part of the filter media, making the dirty filter BETTER for stopping additional dirt.

The worst thing you can do to an oiled-gauze filter is to clean it too often. If you don't have an eighth of an inch of crap on the outside, leave it the hell alone. At most--add a LITTLE bit of oil to the clean side of the gauze to replenish what the dirt has wicked away. This used to be part of the instructions on the K&N web site. They removed this advice in favor of using an air-filter restriction indicator. When the indicator shows restriction, clean the filter.

Restriction indicators are available for < $25, or on salvage-yard diesel pickups. They come with various mounting and plumbing variations.

www.amazon.com/WIX-Filters-24801-Filter ... 103&sr=8-3

www.amazon.com/ACDelco-AFM4-Professiona ... 103&sr=8-2

www.amazon.com/Cleaner-Filter-Indicator ... 103&sr=8-7

[Krooser]

New/"clean" oiled-gauze (K&N style) filters are not as effective as dirty oiled-gauze filters. As dirt builds up on the filter, it wicks oil from the gauze, making it attract more dirt. The oiled-dirt build-up on the outside becomes part of the filter media, making the dirty filter BETTER for stopping additional dirt.

The worst thing you can do to an oiled-gauze filter is to clean it too often. If you don't have an eighth of an inch of crap on the outside, leave it the hell alone. At most--add a LITTLE bit of oil to the clean side of the gauze to replenish what the dirt has wicked away. This used to be part of the instructions on the K&N web site. They removed this advice in favor of using an air-filter restriction indicator. When the indicator shows restriction, clean the filter.

Restriction indicators are available for < $25, or on salvage-yard diesel pickups. They come with various mounting and plumbing variations.

www.amazon.com/WIX-Filters-24801-Filter ... 103&sr=8-3

www.amazon.com/ACDelco-AFM4-Professiona ... 103&sr=8-2

www.amazon.com/Cleaner-Filter-Indicator ... 103&sr=8-7

Good point....

[modok]

Foam works well if cleaned and re-oiled often. Foam seems to SLOW the dirt down a lot, takes a long time to get through, but not "stop" it.
Cotton is best left alone as long as possible, as said they filter worst right after cleaning.

R2C makes some FANTASTIC filters that actually filter....so well they will plug and need cleaning often.

[pcnsd]

New/"clean" oiled-gauze (K&N style) filters are not as effective as dirty oiled-gauze filters. As dirt builds up on the filter, it wicks oil from the gauze, making it attract more dirt. The oiled-dirt build-up on the outside becomes part of the filter media, making the dirty filter BETTER for stopping additional dirt.

The worst thing you can do to an oiled-gauze filter is to clean it too often. If you don't have an eighth of an inch of crap on the outside, leave it the hell alone. At most--add a LITTLE bit of oil to the clean side of the gauze to replenish what the dirt has wicked away. This used to be part of the instructions on the K&N web site. They removed this advice in favor of using an air-filter restriction indicator. When the indicator shows restriction, clean the filter.

Restriction indicators are available for < $25, or on salvage-yard diesel pickups. They come with various mounting and plumbing variations.

www.amazon.com/WIX-Filters-24801-Filter ... 103&sr=8-3

www.amazon.com/ACDelco-AFM4-Professiona ... 103&sr=8-2

www.amazon.com/Cleaner-Filter-Indicator ... 103&sr=8-7

I previously mentioned that the bulk of air-filter marketing is testimonial. It is that way for a reason. The reason K&N no longer makes the above claim is because it is not true and there are trade commissions in the US and Europe threatening to impose fines and recalls on products with false and/or misleading advertisements. If K&N could say anything other than their filters have less flow restriction compared to paper and work in wet environments, they would, but they can't. Paper filters have the greatest flow restriction per area and as one should expect, the best filtering of small particulate. They don't like water. Oiled foam and gauze filters work in wet environments and have higher flow rates per area, but pass more dirt as a direct result of their higher flow rates. There is never a free ride. You can't have both high flow rates per area and a high filtering efficiency of small particulate.
I will continue to clean and/or change my oiled foam and gauze filters as often as possible. I recommend that course to others.

[BLstangin]

Anyone run the wix racing 46946r they told me that one only flows 73 cfm and is made for dirt track racing, maybe try that and an outerwears? I don’t care if it kills some power because if the motor chews up rings in 15 nights it’s down on power for half of that anyway, the motor will run lots longer and make more power longer even if the filter kills some, to be honest most of the time the tracks slick off and you can’t use all the power they make anyway. That has been our biggest struggle other than keeping the dirt out of it.

[barnym17]

Use a napa or wix filter without the r on the end of the part number. The R filters are normally less restrictive but pass more dirt. Use sure seal gasket or silicone the base to the carb. Use a gasket for the air cleaner retaining nut plus cover that with duct tape(we aint trying for pretty here). Also the stock replacement filter for mid 80's chevy truck with 6.2 diesel work well they come with a foam prefilter and are 14x3.AS others have said grease to seal filter to housing as well.

[stealth]

Pipe carb to a nice big truck filter inside car....