05-13-2007, 09:36 PM #1
prefilter over air intake causing lose of rpms
just thought i would share some info on prefiler material. ever since the begining of this riding season i have been searching for some lost rpms. After speaking with a few forum members, I decided to do a back 2 back test with and without the prefilter over my rear air intake.
with prefilter = 7600-7650, without = 7800-7850. 200 rpm difference . i know Dan (rxp'in in mi) has personally been to the outerwears office/facility in MI and was told by an employee that it does in fact restrict air flow.
i also removed the 2 flow rites i had in the grab bar and that gained me another 50 rpms.
to solve the problem, i am going to attach a fine wire mesh/window screen over the rear intake where the prefilter material would sit. the mesh would be fine enough to break up any big water drops and keep debris out. i will leave the 2 flow rites in the grab bar for piece of mind since i do ride in rough conditions form time to time. i am going to make a "cover" for the air inlet to be placed on when trailoring so no dust or anything can get in there while on the road.
btw, i dont have the riva "pro series" prefilter ($159). its just a piece of outerwears i cut to size. im not sure if the riva is the same or not.
05-13-2007, 10:08 PM #2
Just to add to this thread A few yrs ago Jerry and I did back to back tests And even waited to our skis cooled off with the pre filters on the original riva intakes , the pre filter made No difference at all we did the tests then called each other up to share results way back ... neither of us lost any RPMs
05-13-2007, 10:10 PM #3
I`ll dare to differ with ya. But I`m a daring kinda dude. In the world of EMS and fuel injection,,,everything counts. Everything has a bearing on everything else. When the mods go up, the little things make a difference.
05-13-2007, 10:16 PM #4
05-13-2007, 10:23 PM #5
BINGO,,,this is what I experience evrytime riding witht he rear inatke. I wont ditch it,,but if i rode flat,,,id run no screen.
05-13-2007, 10:26 PM #6
I got it up front with a 4 inch intake. no rpm loss with stage 1, but now you guys have me thinking... I will test with/without tomorrow
05-13-2007, 10:30 PM #7
Without question,,lemme put a screen in front of your mouth when you breathe. Bet you wanna remove it.
05-13-2007, 10:34 PM #8
not if it stops the stems and seeds from going down my throat...
05-13-2007, 10:44 PM #9
my motor turns that to non existence. That means not even ash.
05-13-2007, 10:48 PM #10
on two strokes with Prok flame arrestors the outerwears dropped 60-70 rpm. if the area of the prefilter material is large enough it won't affect RPM.
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