Air filter suggestions

[TouringBubble]

Anyone have some good data on this topic?

I need a short-style cone filter for my application. Would you recommend a dry filter, oiled cloth (K&N) or an oiled foam option?

This is for the Beetle. There are two NACA feeds from the rear quarter windows that feed an airbox mounted at the firewall (in the rear). In the airbox there are two 3" intake pipes that need something on them. The pipes go straight to the TBs.

So, the intake is about 4' in the air, but also halfway down the car.

As we all know, Shag Bark can be quite dusty. It sounds like all of the options have downsides ... paper can tear if not replaced often or in heavy dust environments, oiled cloth tends to let more dust through in any scenario but is not likely to fail, and the foam filters are great for dust but water tends to be catastrophic.

I'd love to have some input. Thanks!

Just looking around for affordable options, I found the Spectre brand stuff at Advance for around $20 for the dry filters or oiled cloth versions. The foam ones from SI are $15 ... http://www.siliconeintakes.com/produ...8884de7663df49. Of course, K&N is an option (I heard they were developed originally for motorscross use), but I'm not sure they are worth 2x the cost if they don't filter better. As we all know, K&N advertises horsepower, not filtration.

[engled]

The best thing about K&N is the shear number of different sizes they make.

http://www.knfilters.com/search/universal.aspx

[TouringBubble]

I need a 3" ID connection. Pretty standard. And, based on that catalogue, K&N doesn't have a low profile version in the 3" ID.

[JohnW8]

Get a single filter for your air box and not individual filter for the tubes

Naca funnels air to airbox { filter} filtered air feeds lines to TBs

[Cholewa]

Run an interior home style filter for the naca's, and then a car filter for your actual intake like w8 suggests.

Big sheet of reinforced fiberglass or whatever they use for AC filters.

[TouringBubble]

A big HVAC filter would most likely not stand up to the pressure of automotive use. They are made for a ton of volume, but not a lot of velocity. They would buckle.

What would be the benefit of using a panel style filter for the airbox rather than individual cone filters? The box has 2 feeds, which I can easily move around as it's not built yet. But, adding a panel filter and an easy way to mount/access/change it would complicate the box design a bit. I'd really need to have a good reason to do this.

The current design is essentially 2 short ram style intakes. One for each bank of the engine. The box is simply to seal the intakes from the cabin and collect fresh air from the NACA ducts. It also serves to balance the airflow between the 2 intakes and individual feeds from the NACAs.

[engled]

I need a 3" ID connection. Pretty standard. And, based on that catalogue, K&N doesn't have a low profile version in the 3" ID.

2", how much lower do you need?

http://www.knfilters.com/search/product.aspx?Prod=RA-097V

[kilgojr]

If you find that your filters are not filtering enough, you can always purchase a "Pre-filter wrap" like what the desert guys run.

If I were building the car, I would look to see what those guys were running, and then run that. If the filter can take the Baja, then it should be able to last Shagbark. Your only going to be running for 45 - 60 seconds and if you are pulling in air from the naca ducts it should be pulling in from the front of the car, so you'll be working with just the residual dust in the air, and not the dust being kicked up from the rear of the car.

Here is some info from desert racers:

http://www.ctracing.com/air.htm

[TouringBubble]

2", how much lower do you need?

http://www.knfilters.com/search/prod...x?Prod=RA-097V

Ah, I was looking at the tapered cone filters, not the flat ones. Thanks!

If you find that your filters are not filtering enough, you can always purchase a "Pre-filter wrap" like what the desert guys run.

If I were building the car, I would look to see what those guys were running, and then run that. If the filter can take the Baja, then it should be able to last Shagbark. Your only going to be running for 45 - 60 seconds and if you are pulling in air from the naca ducts it should be pulling in from the front of the car, so you'll be working with just the residual dust in the air, and not the dust being kicked up from the rear of the car.

Here is some info from desert racers:

http://www.ctracing.com/air.htm

I've seen the filter wraps, and those will definitely be utilized.

as far as the NACAs though, it's a rear engine car. The NACAs are on the rear quarter windows feeding air to the firewall in the rear of the car. Not ideal, but there is no simple way to run fresh air from the nose all the way back.

[JohnW8]

What would be the benefit of using a panel style filter for the airbox rather than individual cone filters? The box has 2 feeds, which I can easily move around as it's not built yet. But, adding a panel filter and an easy way to mount/access/change it would complicate the box design a bit. I'd really need to have a good reason to do this.

1 filter is easier to maintain, cheaper to buy and with less restriction.

(Of course I'm writing this with no idea what you intake setup looks like.)

[TouringBubble]

This help?

[river mouse]

I have run a K&N on the Field Mouse for 4 years now and it has done a great job, the inside of the carburetor is clean no sign of dust at all. I run a old Toyota truck, filter location is stock and a lot of dust gets under the hood. I agree with John 1 filter is cheaper and easier to maintain. Since the filter box has not been built yet i would design to that. With flex pipe something similar to dryer vent you could mount the actual intake anywhere, including the top of the car.
Miles

[TouringBubble]

The top of the car as considered, but the NACA duct option was decided on after going through several options. I'll consider the single intake option. It would be nice to maybe have the intake below the TBs, but I'm not sure how possible that is.

[w. leavitt]

Matt, what do the HBB/Offroad guys on Thesamba recommend?

[TouringBubble]

I hate to say it, but I'd rather not reverence The Samba for this specific question. So many of those guys are just "old school." Tech has come a long way. I figured I'd get more current info here, and from the DI forums.