Installing twin K&N air filters help...

[red67]

what do you do with these babies when you install twin K&N filters on webers?...

[911pcars]

Keep the crankcase breather hose (upper arrow) in place. It goes from crankcase to the oil tank. Another hose at the tank (at the filler neck) normally vents to the factory air cleaner. Excess fuel vapor (and sometimes oil) then vents to the atmosphere (and whatever is beyond the sheet metal) through the small (lower arrow).

Any attempt to vent from the end of the crankcase hose will result in much oil exiting the engine. The path to the oil tank slows down oil velocity and helps separate oil/fuel from air.

With individual air cleaners, the typical breather setup is to install a catch can to the hose from the oil filler neck. From the can, you can vent to atmosphere through a small filter or plumb the vapor back to the intake via hoses to each filter. On K&Ns, there's a provision on each metal top to install a rubber bushing to capture such a hose from a catch can.

The catch can itself provides another large volume area to separate any liquid oil and gas from the vapor before venting to the intake or to atmosphere.

Hope this helps,
Sherwood

[red67]

Many thanks Sherwood, i think i got you.
when i read your post i understand that i labelled up the wrong hose - doh.
should have been this one as you correctly write.



oh yeah the holes on the side of the rainshields must be for the bushings it makes a little more sense now..


i need to do some shopping!
has anyone got any pictures for reference of their set up? (with a catch can if poss?)

[Mo_Gearhead]

I investigated the numerous 'catch can' applications. But went to O'Reilly Automotive, bought a chrome and paper breather and stuck it in that hose.

Didn't even attach it anywhere...it lays back on the top shock mount area.

Over 1000 miles now, no problems.

(Let me know if you want a photo.)

[red67]

Originally Posted by Mo_Gearhead

I investigated the numerous 'catch can' applications. But went to O'Rielly Automotive, bought a chrome and paper breather and stuck it in that hose.

Didn't even attach it anywhere...it lays back on the top shock mount area.

Over 1000 miles now, no problems.

(Let me know if you want a photo.)

a photo - yeah that would be great. thanks.
found this on catch cans... looks a little over the top...
http://www.early911sregistry.org/forum/showthread.php?t=10057

[RoninLB]

i've seen K&N breather only attached to fill neck 1" hole.

I use a up angled 1.5' hose then K&N only. Some say their engines smoke so much they need a catch can. Some say their track requires a catch can.

[Mo_Gearhead]

From the oil filler neck:



to the rear shock area:



1000 miles and as clean as the day I installed it. Just venting to the atmosphere seems to be working fine for a 'street only' car.

Why suck crankcase fumes back into a combustion chamber to pollute the incoming fuel/air mix if it isn't necessary?

Most racing bodies DO require a can.

[bkreigsr]

K&N sells a nipple adapter for a marine application that fits between the top and base of the filter. I used one of the adapters to run a vacuum line to the catch can.
Bill K