32 replies to this topic

[samsfern]

i often see air filter socks in use at race meetings, they never get sucked in, im not saying its not possible as it would be if the sock werent properly secured. As for filteration, they are made up of 3 layers, corse medium and fine. We have used them on rally cars competing in deserts at work, then stripped the engines after the rally, to see no real sign of wear. So in my opinion, socks are best.

[Ethel]

Whatever you use more surface area = more flow. Foam filters will have a lot less of it than pleated paper or cotton gauze . It would have to flow much better to compensate and that's without considering the effect of higher air velocity as you squeeze more air through a smaller area. You'd need to be on the road or on the rollers to see how a filter behaves under full engine load.

[Sprocket]

My experience of the foam socks on the BMW conversion, is not good. Firstly, that video posted, is mine, the car is a friends and yes the socks were incorrectly installed. This however does not detract from the fact that even when installed as prescribed, they still restrict the airflow. I changed the foam socks for a decent K&N style filters and had to remove a load of air at idle to get it back to the correct idle speed and fueling. Un oiled they flow a bit better but then your engine will ingest fine gritty dust, so they are not such good filters when they flow reasonably (without the oil)

horiblethem foam things. If you use one un oiled, I'd check the carb throat for a gritty residue.

K&N everytime, or, at least a decent cotton gauze filter, and, NOT the cheap Chinese ones with a heavey wire mesh!

This is my experience and opinion, and should be considered as that