User Tag List

Results 1 to 8 of 8
  1. #1
    Join Date
    Sep 2008
    Location
    charlestown, ri
    Posts
    321
    Thanks (Given)
    0
    Thanks (Received)
    12
    Likes (Given)
    3
    Likes (Received)
    44
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    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.

    Click image for larger version. 

Name:	120 140 early.jpg 
Views:	12 
Size:	33.6 KB 
ID:	535929Click image for larger version. 

Name:	130hp intake.jpeg 
Views:	11 
Size:	129.0 KB 
ID:	535928

  2. #2
    Join Date
    Jun 2007
    Location
    Singapore/Melbourne/Italy
    Posts
    9,218
    Thanks (Given)
    1039
    Thanks (Received)
    382
    Likes (Given)
    4491
    Likes (Received)
    2079
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    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

  3. #3
    Join Date
    Sep 2008
    Location
    charlestown, ri
    Posts
    321
    Thanks (Given)
    0
    Thanks (Received)
    12
    Likes (Given)
    3
    Likes (Received)
    44
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    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?

  4. #4
    Join Date
    Jun 2007
    Location
    Singapore/Melbourne/Italy
    Posts
    9,218
    Thanks (Given)
    1039
    Thanks (Received)
    382
    Likes (Given)
    4491
    Likes (Received)
    2079
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Revenge22 View Post
    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?
    teacups are the worst
    think of reed valve 2 strokes, in a very short time air pressure has to push the air from outside of the carb and through the reeds
    a straight line is best
    Last edited by powerabout; 09-05-2024 at 04:47 AM.

  5. #5
    Join Date
    Sep 2008
    Location
    charlestown, ri
    Posts
    321
    Thanks (Given)
    0
    Thanks (Received)
    12
    Likes (Given)
    3
    Likes (Received)
    44
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    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

  6. #6
    Join Date
    Jun 2007
    Location
    Singapore/Melbourne/Italy
    Posts
    9,218
    Thanks (Given)
    1039
    Thanks (Received)
    382
    Likes (Given)
    4491
    Likes (Received)
    2079
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Revenge22 View Post
    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
    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.

  7. #7
    Join Date
    May 2001
    Location
    Hickory NC
    Posts
    5,600
    Thanks (Given)
    19
    Thanks (Received)
    256
    Likes (Given)
    206
    Likes (Received)
    482
    Mentioned
    5 Post(s)
    Tagged
    1 Thread(s)
    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.

  8. Thanks powerabout thanked for this post
  9. #8
    Join Date
    Sep 2008
    Location
    charlestown, ri
    Posts
    321
    Thanks (Given)
    0
    Thanks (Received)
    12
    Likes (Given)
    3
    Likes (Received)
    44
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    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?




    Click image for larger version. 

Name:	397497.jpg 
Views:	8 
Size:	5.0 KB 
ID:	536026
    Last edited by Revenge22; 09-06-2024 at 01:24 PM.

Similar Threads

  1. OMC looper intake
    By gspurlock in forum Technical Discussion
    Replies: 2
    Last Post: 01-03-2003, 11:46 AM
  2. V4 Looper intake
    By Laker in forum Technical Discussion
    Replies: 9
    Last Post: 12-22-2002, 01:05 PM
  3. omc looper intake
    By charger19 in forum Technical Discussion
    Replies: 3
    Last Post: 11-05-2001, 08:30 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Frank Mole Transport