Thread: New air box
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Old 01-12-2013, 02:17 AM   #250
Spark01's Avatar
Joined: Aug 2010
Location: The Netherlands
Oddometer: 306
Originally Posted by pdxmotorhead View Post
Just thought I'd kick in some experience on these style filters...

I use the same manufacturer filter on a twin cam Cosworth engine... Just 2 more velocity stacks.. :)

None of the pictures of the filters I've seen on this thread are anywhere near as dirty as we get them on the track.
They are really tolerant of dirt..

Always use grease on the sealing surface, nasty thick grease. I use red-line wheel bearing grease.

We found on the midget would have lean out problems and the fix was to put a aluminum dam around the front of the filter. About 1" away.

If you dyno a engine with velocity stacks you'll see an interesting effect, its called a fuel fog column, it will extend 1 to 2 inches above the velocity stack. (The dyno operator is world class and had lots of experience with formula engines... ) With the engine under power if air blows across the top of the stacks the mixture goes crazy. He demonstrated with the hose from a shop vacume. I suspect if you put a air dam in front of the filter so the air coming through the body work enters the filter form the sides but cant come straight in it will help keep the buffeting down..

Short stacks for RPM & HP long stacks for low end grunt and torque.

thanks that inside, but i would suspect if we put a "airdam" in front of the filter. then the most air comes from below and then we are sucking hot air due to the heat of the engine. and that doesn't help for power. however if we put a plate beneath the filter so no hot air can come from that way and a airdam in front of the filter then maybe it would work....?. (cold air enters from behind in the airbox)

p.s do you mean such kind of mist above the stacks like in this video:
'10 990SMT

Spark01 screwed with this post 01-12-2013 at 07:19 AM
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