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Post by drawkward on Mar 10, 2010 16:46:48 GMT -5
I read somewhere that having an open filter actually decreases performance on a 2 stroke, due to the loss of back pressure from the closed box...
What do you guys think, from experience?
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Post by 90GTVert on Mar 10, 2010 18:29:21 GMT -5
I don't really know from experience. I ran a stock airbox until I got a carb big enough that the airbox wouldn't fit it. I tried swapping to a K&N when I first got my scoot, but it just wasn't happening without jets and I never bothered. I don't see the need for an open filter on most setups, but I wouldn't think they'd hurt performance assuming it's jetted properly. If back pressure is a concern for the intake tract, I'd think it would be primarily for idle or low throttle settings or throttle response. At high RPM you want that piston to draw in as much air and fuel as it can. Ideally, you'd run no filter at all and maybe a bell mouth venturi kind of setup to allow air to travel into the carb with the least resistance. If you go with an open filter and start seeing issues with idle and throttle response, try sticking a boost bottle on there and see what happens.
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Post by drawkward on Mar 10, 2010 20:09:44 GMT -5
If you go with an open filter and start seeing issues with idle and throttle response, try sticking a boost bottle on there and see what happens. ;D I think I'll give that a shot! |
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Post by 190mech on Mar 10, 2010 21:38:54 GMT -5
With proper jetting an open airfilter should perform better,I hate
the noise though,it drowns out the sweet sound of an expansion
chamber doing its work.Velocity stacks were the thing on 2T road
racers back in the day....
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Post by Fox on Mar 10, 2010 22:29:49 GMT -5
I've heard that 2 strokes perform better with some back pressure on the exhaust for some reason. I don't think the intake side needs a pressure vessel.
Don't the reed valves stop the pressure from spitting out the intake/carburetor on the compression part of the piston's stroke?
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Post by drawkward on Mar 10, 2010 22:35:51 GMT -5
From what I understand, It takes a pressure wave to close the reeds. There has to be some air escaping, even if for the shortest moment before the reeds close... Right? I could be way off. But isn't that what makes having a boost bottle worth anything?
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Post by 90GTVert on Mar 11, 2010 16:39:45 GMT -5
Yeah, reed valves are not very efficient.
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