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Thread: Best intake for V4 OMC Looper?
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09-04-2024, 01:17 PM #15000 RPM
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Best intake for V4 OMC Looper?
Hi guys a bit confused on what intake is the best (most flowing) for the V4 loopers (v6 too id think). It appears the early ones in the 120/140hp in 1985 part # 394322 looks to be the least restrictive, as it doest have a check valve hole in it, and looks like a "smoother ramp" of intake charge the way its designed. But we all know the 130hp was the best of them all, yet come with part # 434370 that looks more restrictive. can anyone confirm if swapping the older intake on to a later 1995-up 130/135 would give it more punch and/or top end? just trying to squeeze everything out of a 2001 135hp build. 1st pic is the 1st year 120/140hp intake, 2nd is from a 130/135. see the more pronounced "step" and recirc valve fitting smack dab in the middle? the circular "teacup" intake seems to be really restrictive so i wont include them, but know all will accept 6 petal reeds.
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09-04-2024, 06:30 PM #2Screaming And Flying!
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yep that one, can add a bit of filler in the corners to make it better
or make your own an drop the carbs down for a better straight in shot
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09-04-2024, 07:09 PM #35000 RPM
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thanks.so the early ones are better? wouldn't adding filler make them more like the "teacups" that are more restrictive? or are the teacups actually better?
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09-05-2024, 02:45 AM #4Screaming And Flying!
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09-05-2024, 08:14 PM #55000 RPM
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makes sense thanks. Al Stoker... reading some old posts on the subject... said if the intake has a slant, you are good. the teacips are like a wall... a 90 degree wall. But i'm betting OMC tried those in an attempt to get a smoother/more consistent idle out of these. problem solved with the 130
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09-05-2024, 10:34 PM #6Screaming And Flying!
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Yes in most cases the 90 degree loopers made the power they required so design was for other issues.
Al made his own inlet to help straighten out the path.
Stock lower cowl becomes an issue but getting carbs lower for straight path helps lots.
I know some OMC guys in oz that worked on that by milling the front off the inlet amd making a new plate to mount the carbs.Last edited by powerabout; 09-05-2024 at 10:37 PM.
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09-06-2024, 09:05 AM #7Scream And Fly VIP
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Best stock is 86 to 90. Ones pictured are close but can be made to flow better by filling them in and reshaping. The tea cup was a production change without engineering approval, it was to make castings easier. The higher the rpm the more critical this all becomes with straighter paths helping to make high end performance. What a lot of people don't consider is what the difference make in signal to the carb and how it effects jetting, of course porting has a big effect as well.
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09-06-2024, 01:05 PM #85000 RPM
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thanks Al great info. But looking at the parts diagrams, now i'm really confused. 1986-1993 uses #397497, which looks to be the teacups? or is there something about the specific castings for 1986-1990 that makes them better, despite the same part #'s? this is # 397497... isn't this a "teacup"? but you are saying they are the best?
Last edited by Revenge22; 09-06-2024 at 01:24 PM.
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