With K&N and After Foam

[Problem Solver]

Micro sprint racing in Oklahoma is a very big deal and many racers still use K&N. I just wanted to share with you about a man who has been racing for many years and his father long before that and what they have found. Vic Sherrell is his name, his son Matt drives a 600cc Micro and they had used K&N filters for many years until last year when they began testing a Foam filter for the first time. With the K&N, Vic told me there was always a gritty, sticky substance in the bottom of the carbs and that he had always cleaned them every two weeks. Since going to the Foam filter, he has completely eliminated the gritty substance (I suppose it is dirt since they race on a dirt-track) and now they only have to clean their carbs once every 6 weeks. He brought this to his engine builder's attention (Bob Mosley of MoMo's Racing Engines of Tulsa) and it appears Bob has now began going away from the K&N filters too. Just thought I would share that with all of you.

 

[metroplex]

I got your email and this is my response:

quote:

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What bottom part of the carb?

I don't buy his story for several reasons. If it were completely true then everyone who has a K&N would have HIGH levels of Silicon in their UOAs. I've seen UOAs with silicone as low as 1 and as high as 25 ppm w/ the K&N but none of the levels have been directly attributed to the use of a K&N filter.

Second, foam filters haven't been proven to stop dirt either - oil can still seep through and make a huge mess.

With a carburetor, you would see more residue at the airhorn if the K&N wasn't working properly. Why the airhorn and not the "bottom part" of the carb? Because the venturi have a constant stream of gas/fuel and air. Any dirt or residue in there would be dissolved by the fuel/air mixture and moved into the combustion chambers. The airhorn is the only part where no fuel can reach the residue and clean it.

If you said Vic noticed an increase in dirt and gunk on the TOP part of the carb, then maybe I'd buy his story but the bottom part? what bottom part? Anything below the airhorn sees a lot of air/fuel mixture stream and is always "clean".

On my Ford 2-bbl 2150, the airhorn does get dirty w/ the paper filter but my venturi cones and the two bores are always clean.

-Charlie

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K&N oil is just clear cutting oil w/ dye. Nothing special about it, it'd dissolve in 93 octane or any fuel. Methanol and alcohols would also dissolve it, altho I'm not sure about the racing motors.

I use foam air filters for my PCs and even tho they catch a LOT of dust, there's a layer of fine dust on the inside. Paper is too restrictive and my next step is to just use cotton gauze w/ a wire screen.

[ June 20, 2003, 01:41 PM: Message edited by: metroplex ]