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Anyone have knowledge about porting?


Dragg-on

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Ive got drag cylinders ported making 90hp (350cc). my intakes are not big at all, but There are shops around here that port that think a drag port must have the intakes big, cut top to bottom. how do I explain to these rookies that bigger is not always better?

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most engine builders say the banshee intake is already big enough. they just reshape them a little.i seen some really hogged out intakes before.didn t run faster than the smaller reshaped ones.transfers and exhaust is where the builders do the real magic.

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Tell them that the only thing they will accomplish by enlarging the intakes is

to decrease crank case volume & bottom end response with absolutely no

increase in H.P. If they want to prove it to themselves port a set of cylinders

but do nothing to the intakes & dyno them. Then go back and open them up

& re-dyno them. There will be no diff. in H.P. Opening up the intakes just

slows down air velocity which kills bottom end response. Just my .02.

 

-Downside

 

98' Shee & 89' 250R ooops........ did I say the "R" word.

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Drag port and track motors can use a little extra volume. There are just better ways of getting it without hogging out the intakes while maintaining the effects of intake velocity, not to mention maintaining skirt support and minimizing liner wear. Remember, intake velocity doesn't make more peak H.P., it does make for better throttle response though...Jim

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