set back pump
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 14 of 18

Thread:
set back pump

  1. #1
    MPR FAB southwind011's Avatar
    Join Date
    Oct 2009
    Location
    riverside ca
    Posts
    363

    Default set back pump

    I have a 18 ft southwind with a Berkeley jc and the intake is out of the hull.would it be worth it to set the pump back since the intake is out of the boat?Right now it has a stock BBC and i plan on building around a 500hp motor with in the next year or two.what would be the pros and cons of doing the set back now.I have a bad porpoise with the stock setup.would this help me or not?
    Last edited by southwind011; 08-18-2011 at 11:59 PM.

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member ugly duck's Avatar
    Join Date
    Jul 2010
    Location
    OGDEN UTAH
    Posts
    346

    Default

    we recently set the pump back and blueprinted the bottom of that same model boat ,along with machining the intake for a ride plate and built the plate installed it , the boat runs very nice now and we picked up a bit on the mph side. the owner is running a healthy ford (sin) and at 6200ft adjusted elevation hes running 83.4 gps that's damn respectable at this altitude with a aspirated pump gas motor so yup id go for it
    (GN7)Just a simple waste of perfectly good sour mash. If you need a fuel, use something that will poison you, not something that makes you buzzed.

  4. #3
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,818

    Default

    Quote Originally Posted by southwind011 View Post
    I have a 18 ft southwind with a Berkeley jc and the intake is out of the hull.would it be worth it to set the pump back since the intake is out of the boat?Right now it has a stock BBC and i plan on building around a 500hp motor with in the next year or two.what would be the pros and cons of doing the set back now.I have a bad porpoise with the stock setup.would this help me or not?
    DO-IT. I have done a few of the early 18 southwind v-bottoms and nothing wakes them up faster. I have gone 3" back and my son is building one as we speak and he went out the back with it. You HAVE TO set the bottom up correctly for it to work proper. M

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Senior Member zacho!'s Avatar
    Join Date
    Jun 2009
    Location
    tucson, Arizona
    Posts
    979

    Default

    Quote Originally Posted by ol guy View Post
    DO-IT. I have done a few of the early 18 southwind v-bottoms and nothing wakes them up faster. I have gone 3" back and my son is building one as we speak and he went out the back with it. You HAVE TO set the bottom up correctly for it to work proper. M
    X2. I set the intake back 3" on my Kachina (very similar if not splashed I believe), and best mod to date. My Buddys boat on the other hand,with with same everything pump and similar HP and semi v hull, feels dangerous to me. He's got 3/4" hook the last 3 or 4 feet of hull. Not fun to drive, let alone ride in...

    Edit: I just read futs' reply and reread OP - must've missed the porpoise statement. never had anything weird prior to set back in my deal...
    Last edited by zacho!; 08-19-2011 at 04:44 PM.

  7. #5
    Senior Member Futs's Avatar
    Join Date
    Dec 2007
    Location
    Orange CA, Big River
    Posts
    4,549

    Default

    Quote Originally Posted by southwind011 View Post
    I have a 18 ft southwind with a Berkeley jc and the intake is out of the hull.would it be worth it to set the pump back since the intake is out of the boat?Right now it has a stock BBC and i plan on building around a 500hp motor with in the next year or two.what would be the pros and cons of doing the set back now.I have a bad porpoise with the stock setup.would this help me or not?
    opening a big can of worms...........jmo

  8. #6
    B1 Racing cs19's Avatar
    Join Date
    Dec 2007
    Posts
    6,523

    Default

    Quote Originally Posted by Futs View Post
    opening a big can of worms...........jmo
    I agree, can be made to work really well but you gotta be careful. Thing could be worse as far as porpoising goes.

  9. #7
    Senior Member ol guy's Avatar
    Join Date
    Mar 2008
    Location
    Lake Elsinore Ca
    Posts
    3,818

    Default

    Quote Originally Posted by cs19 View Post
    I agree, can be made to work really well but you gotta be careful. Thing could be worse as far as porpoising goes.
    With all due respect futs and cs that is why I stated the bottom must be set-up as well. Along with a ride plate,shoe and diverter. If he has the intake out now then do it now. Do it right the first time and be done underneath. M

  10. #8
    Senior Member ICECREAMAN's Avatar
    Join Date
    May 2009
    Posts
    2,426

    Default

    Quote Originally Posted by ol guy View Post
    With all due respect futs and cs that is why I stated the bottom must be set-up as well. Along with a ride plate,shoe and diverter. If he has the intake out now then do it now. Do it right the first time and be done underneath. M
    Could you elaborate on what you would do when you say " bottom set-up" Are you talking just make sure there's no hook, or do you need to create a Delta pad? Is there some sort of standard or starting point? What is the criteria when considering a set back pump? Inquiring minds are also curious.

  11. #9
    Senior Member zacho!'s Avatar
    Join Date
    Jun 2009
    Location
    tucson, Arizona
    Posts
    979

    Default

    Quote Originally Posted by ICECREAMAN View Post
    Could you elaborate on what you would do when you say " bottom set-up" Are you talking just make sure there's no hook, or do you need to create a Delta pad? Is there some sort of standard or starting point? What is the criteria when considering a set back pump? Inquiring minds are also curious.
    Too much hook is very bad in my humble AZ experience...

  12. #10
    Senior Member Futs's Avatar
    Join Date
    Dec 2007
    Location
    Orange CA, Big River
    Posts
    4,549

    Default

    So are you guys looking at the rocker that was built into the boat? Some people place there straight edge right on the rocker and think, wow, this has a ton of hook because the straight edge has a 1/4" gap or more, when in fact that rocker needs to be there to let the boat roll over so to speak. I hear everyone talking about hook, do most not know about rocker?Set backs have a time and place. It can work well on one and do terriable things to the next. If this is a ski boat and your looking to enjoy it, just leave it alone. If its an all out max effort, well, then cut the intake for a shoe, move it back a few inches, and get the bottom done. Then let the headache start when you cant figure out how to hardware the thing and your wasting your time dicking with the boat rather than enjoying it.


    Dont get me wrong here, Im all about performance, but when your taking a 1/4 stringer boat and seting the pump back, its going to do funky things to the bottom as far as structual integrity.

    This is just my opinion. im not a know it all, just been around for awhile and seen some stuff....

  13. #11
    Senior Member jetboatperformance's Avatar
    Join Date
    Dec 2007
    Location
    Atascadero Calif
    Posts
    7,464

    Default

    Quote Originally Posted by southwind011 View Post
    I have a 18 ft southwind with a Berkeley jc and the intake is out of the hull.would it be worth it to set the pump back since the intake is out of the boat?Right now it has a stock BBC and i plan on building around a 500hp motor with in the next year or two.what would be the pros and cons of doing the set back now.I have a bad porpoise with the stock setup.would this help me or not?
    Agree with Tim , (potential "worm can" as you were advised above)not every boat will benefit from this , try to sort out and diagnose whats causing the porposing problems with the original setup vs making a huge and significant modification that will require a whole new set of changes and adjustments , pics will help (bottom ,intake area ,jet etc) could be something simple Tom

  14. #12
    MPR FAB southwind011's Avatar
    Join Date
    Oct 2009
    Location
    riverside ca
    Posts
    363

    Default

    What would be the cause of the porpoise with the stock set up? Also I will be replacing the 1/4 stringers with full stringers. Dose anyone have pic of there set up?I would like to see the difference from stock. Thank for all info.

  15. #13
    Senior Member bp298's Avatar
    Join Date
    Dec 2007
    Location
    LHC
    Posts
    6,573

    Default

    knew a guy many years ago that had a sw splash. would run 88 through the traps porpoising like a mother. he tried everything; droop, no droop, short plate, long plate, diverter, bottom blueprint, and everything in between. still porpoised. after exhausting everything he and others could think of, he finally added trim tabs, adjusted them once and the porpoise was gone. and then it would run over 90.
    nobody really wants to add trim tabs. but it's a sure way to eliminate porpoise. sometimes ya just gotta do what ya gotta do...

  16. #14
    Senior Member stoker2001's Avatar
    Join Date
    Dec 2007
    Location
    Folsom,Ca
    Posts
    1,713

    Default

    Quote Originally Posted by bp298 View Post
    nobody really wants to add trim tabs. but it's a sure way to eliminate porpoise. sometimes ya just gotta do what ya gotta do...
    what do i know,but tunnel tabs are mounted on top of tunnels and can affect handleing as well as trim tabs that are mounted level with bottom of boat..
    Whacker Smacker M/E #561 IHBA "first looser"champ 2006&2007&Sportsman Driver of the Year

+ Reply to Thread
Page 1 of 2 1 2 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Digg This Thread

Posting Permissions

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

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95