Page 6 of 6 FirstFirst ... 4 5 6
Results 51 to 57 of 57
  1. #51
    NOIDEA's Avatar
    Join Date
    Mar 2013
    Location
    South Africa
    Posts
    261
    +1
    18
    Quote Originally Posted by DSR View Post
    .......random stupid idea #3........

    If the F has 5 deg. Built into the steering nozzle and 3 deg. works better....... I believe the bolt pattern of the venturi to the pump body is symmetrical, it would make sense (at least in my mind) to put a 2.5 deg wedge in upside-down?
    That would give you most of the better angle and also lowers the pump thrust line slightly, which is also a good thing.
    The full-size jet boats have been doing this for years with what's called a "droop snoot" (Yeah, I know, stupid name....).

    This is what I was thinking, but obviously, this is a much more exaggerated version.......

    Attachment 429279
    Yes I also believe it is symmetrical, that is actually a very good idea I also think that the 5 degrees is a bit to much. I’ve seen on the Yamaha and seadoo threads that most of the guys run a 3 degrees setup as most of them get the best results with that.

    Cheers
    Johnny

  2. #52
    DSR's Avatar
    Join Date
    Feb 2018
    Location
    Allegan, MI
    Posts
    75
    +1
    2
    Hi Johnny,

    I'm glad that Da Boss is doing good,

    The cone design is taking a little longer than I had anticipated (nothing new there with my luck.... ),
    A minor speed bump in the process (had to switch CAD programs right in the middle of it and the learning curve on the new program is trying to kick my a$$....), but making headway. Talked to my buddy with the 3-axis CNC and all set to steal the machine once it's drawn up, so we're good there.

    You might want to hold off on sending those pics (but you can send them if you want. I'd still be happy to take a look at them). I spent some time under my R a couple days ago studying the hull and did some research on some of the faster skis, and I believe I've got a pretty good plan of attack on what needs to be done with it. The worst part of doing it will be getting the hull back to the original shape to do what I'm thinking, BUT... the upside is that pulling the stuff off will be the hardest part of the whole project. Also, the mods I'm thinking of will be layed up right on top of the original hull like you did, so no cutting into the hull, and the hull can be reversed back to the original configuration if it doesn't work as intended (but I've got a sneaking suspicion that it'll work pretty good....). Another benefit is that the mods aren't huge changes and won't add a ton of additional weight to the hull, and the process can be done pretty easily and quickly with structural foam, fiberglass cloth and epoxy resin using some cheap homebuilt tools.

    I'll get some sketches loaded up of my ideas in a bit so you can take a look and see what you think?

    In with doing this, I think tightening up the pump and getting a Solas in it is a really good plan. Did you ever modify the grate on your F? I think that would be a good idea too. Everybody that has cut the 2 and 4 bars out and smoothed / sharpened it say that it really helps with cavitation on the hit.
    Do you happen to have measurements on the intake opening on your F? I know my R is different, but I was surprised that mine is not too far off the size of the GP1200 intake I'm using for the boat. I still have to "wrestle and swear" the grate off my hull and look at the shape of the gullet though.

    The mods to the hull are most likely going to positively change the hull lift and attack angle at speed, so we'll want to hold off on changing the pump thrust angles until that's done to see how the ski acts. Swapping an R nozzle onto the pump (possibly with a wedge) and making it remotely adjustable would be easy enough to do, and I can also see spending some time on the ride plate is in our future too .

    I'm not sure if building a water-jacketed header would be worth the huge amount of time and effort (not to mention the expense). They look badass, but I think Honda actually did a pretty good job on the original exhaust manifold as far as flow shapes and from what I see looking at mine, the ports actually look a little large for the engine size and rpm of the stock setup. You might want to try the turbo swap with the manifold to start with and see what happens? Worst case, you end up building a header...... .

    Thanks Johnny and I'll post up some pics shortly!
    Dave

  3. #53
    DSR's Avatar
    Join Date
    Feb 2018
    Location
    Allegan, MI
    Posts
    75
    +1
    2
    Well Johnny, this is what my twisted little brain came up with.......(yeah, yeah, mom FINALLY let me play with the crayons

    This is gonna be kinda long, but hopefully not too painful to read through......

    OK, my ideas on modifying the hull is to take structural foam, epoxy it on top of the outer strakes (this is in relation to the hull being upside down) and spanning to the base of the inner strakes. Use the tops of the outer strakes and base of the inner strakes as guides, and cut (a hot wire tool would work really well for this and there are youtube videos on hot wire cutting foam. Very slick....), sureform, and/or sand the foam to create flat surfaces straight across from the top of the outer strakes to the base of the inner strakes and carry that surface forward to the tips of the inner strakes. Epoxy foam from the tops of the inner strakes spanning to the keel centerline of the hull over the radius of the keel, and then use the tops of the inner strakes and the keel radius as guides to form flat surfaces.
    On the forward portion of the hull, this will form a "V" down the centerline of the keel. This "V" edge needs to be right down the centerline and straight from front to rear, which should be pretty easy to do using the the strakes and keel radius as guides. At the forward tip of the inner strakes, the flat surfaces of the inner strakes and the outer strakes to the keel centerline will blend to one straight surface from the outer strakes to the keel moving forward towards the bow.
    The open area at the centerline in front of the intake shown in the sketch will be the inside edges of the foam transitioning from the keel centerline to the side edges of the intake and those edges aren't critical, as it will be overlayed by the radius drop keel. it's more important that the deadrise angles moving from the transom forward transition uniformally and be very subtle. Using wood battens as guides will help with verifying the transitions. After filling in the running surfaces, form some separate lift strakes, copying the dimensions and down-angles of the original strakes, and epoxy on top of the originals.





    ......Then more foam to form a radius drop keel to deal with cavitation from the water boundary layer and help load the pump. Dimensionally, it's gonna be trial-and-error just like my project, but it should be the same width as the pump intake and should be at least long enough to extend forward past the front of the engine/rider position. As far as drop, I'm thinking the 1/2" would be a good place to start.
    Then sheath the whole mess in fiberglass cloth and epoxy resin, and finish off with gelcoat, paint, etc.



    The end result of doing this is to create flat surfaces to reduce wetted surface area over radiused surfaces, and filling in the areas between the strakes will reduce deadrise angles, creating more efficient lifting surfaces and increase attack angle at speed. Lowering the lift strakes in relation to the keel, creates even more lift, further reducing wetted surface area. These mods will also create a step between the hull and the side areas of the ride plate, which will also help increase attack angle and reduce wetted surface area on the ride plate.

    The only issue I'm running into on this is that even though glass over foam construction appears to be the best way to do the mods, it's not a method that I'm familiar with. I've posted this question on Boatdesign without much success, but I did some research on it and so far I'm coming up with 2 lb. / cu. ft. polyurethane structural foam, fairing compound to make it perfect, 2 layers of 10 oz. biaxial glass and a top layer of 6 oz. plain-weave glass to provide a good surface for finishing. Maybe you might have a better recipe?

    Whew!!.........Thanks for putting up with my rambling Johnny and let me know what ya think?

    Dave
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	20180310_210211.jpg 
Views:	75 
Size:	66.2 KB 
ID:	429477   Click image for larger version. 

Name:	20180310_210152.jpg 
Views:	80 
Size:	57.4 KB 
ID:	429476  
    Last edited by DSR; 03-12-2018 at 04:18 AM.

  4. #54
    DSR's Avatar
    Join Date
    Feb 2018
    Location
    Allegan, MI
    Posts
    75
    +1
    2
    Hi Johnny,

    Finally got the time to map out the hull and the changes into my simulation program last night and I thought you might be interested to see the results....

    I had to do it with my R because that's what I had here (of course ), but with your F being a bit longer that will only help with a slightly better length-to-beam ratio.

    With the stock hull and an estimated 220 hp @ 4500' ASL, it ended up with 65.9 mph +/-, which I feel is pretty close.....

    With the mods to the hull only and no other changes, I'm coming up with 69.4, and 71.2 mph with 2 deg. less trim.....

    Of course, I'm sure we'll have to play with the it to find the best setup, but it definitely looks like a step in the right direction

    Hopefully that might do the trick?

    Thanks,
    Dave
    Last edited by DSR; 03-12-2018 at 06:15 PM. Reason: Verified simulation results


  5. #55
    DSR's Avatar
    Join Date
    Feb 2018
    Location
    Allegan, MI
    Posts
    75
    +1
    2
    Hi Johnny,

    Well, it looks like I finally beat on the CAD program long enough to make it do what I wanted, so I now have 2 different cones drawn up to try out.....



    The white horizontal lines shows the mapping of the venturi section spanning 90mm into the venturi from the mount flange.
    This is the first design I came up with and I guess I would call this a "contoured flow" cone (for the lack of a better name ).
    My idea here was to try and keep the cross-section of the flow area as consistent as possible moving through the venturi, while still filling more space inside the venturi than the stock cone, to build pressure without choking flow. In my mind, I was aiming for a cone that would benefit both bottom end and top end to provide good performance across the board. (I'm not a scientist and I don't have access to CFD analysis, But I play one on TV and I did stay at a Holiday Inn Express once.... ).
    I'm pretty curious to see if the idea works as intended.



    ....and this parabolic cone is design #2, and with this I was definitely shooting to choke the flow cross-section to see what would happen.
    I'm thinking that this one might be too aggressive, but with the shape of the venturi map, it might just work better than expected.
    Like I tend to say, "only one way to find out......."

    I've got the mount mods and the angle jig plate designs done up to change the cone angles to match wedge plates if they end up getting tried out, but the ones I'm gonna cut for you "should" fit on your existing mount base. With that I'd like to get the length of your cone from base to tip, minus the cap screw head, if I could please. Then the 6061 chips are gonna start flyin!

    Thanks Johnny,
    Dave
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Contoured flow pump cone.JPG 
Views:	70 
Size:	28.4 KB 
ID:	429806   Click image for larger version. 

Name:	Parabolic pump cone.JPG 
Views:	68 
Size:	27.4 KB 
ID:	429807  

  6. #56
    DSR's Avatar
    Join Date
    Feb 2018
    Location
    Allegan, MI
    Posts
    75
    +1
    2
    Hi Johnny, Haven't heard back from ya so I hope everything is going well.

    Just wanted to let you know that it looks like I FINALLY hit paydirt on springs and (hopefully) retainers for our Hondas!

    The springs are shot-peened chrome silicon singles that would be drop-ins and gives us enough seat and open pressure to easily run 25+ lbs. of boost (if we maychance want to do something so ridiculous.... ), and very good resonance specs, so they're not gonna do anything stupid at anything below 12K rpm. I have to get a couple specs on the retainers from the manufacturer that they don't show in the catalog, but so far they look like they're gonna do the trick also.

    The best part is that I can get a set of springs and retainers for $357.00 total to my door! So I'll let you, and anybody else that might be interested, know the lowdown as soon as I verify that everything will do the trick.

    Also took a pass at the injectors, and it looks like I can get my hands on some 50 lb. EV1s (good for 275 hp with boosted BSFC #s), that look like they'll fit by just swapping the Honda injector connectors and terminals on the harness to EV1 connectors (there's plug 'n play adapter harnesses available to change from Honda to EV1, but I don't care for them). I can do a set of injectors and connector kits for $225, which I didn't think was too bad (of course, they have other sizes available also).

    See...... I told you that this "gear-turney-spinney-thinking" thingy was dangerous...........

    If anybody has any questions on any of this, feel free to yell!

    Thanks!
    Dave
    Last edited by DSR; 03-21-2018 at 03:34 PM.

  7. #57
    DSR's Avatar
    Join Date
    Feb 2018
    Location
    Allegan, MI
    Posts
    75
    +1
    2
    Hi everyone,

    If anyone is curious as to what I'm working on in regards to all the brainstorming going on and all these questions, I just wanted to let you all know that I finally got my head out of my butt and started a build thread in the Conversion PWC section to detail my build and provide a log of the trials and tribulations that I'm sure I'll run into in the process (but that's part of the fun........right?......)

    http://www.greenhulk.net/forums/showthread.php?t=269484

    Thanks all and I'm sure I'll have more questions as I go along,

    Dave

Page 6 of 6 FirstFirst ... 4 5 6

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. new member with 91 650sx rebuild questions
    By lariat7.3 in forum Kawasaki PWC Performance (2-stroke)
    Replies: 13
    Last Post: 08-20-2015, 10:52 AM
  2. New member with a few Q's
    By ruger226 in forum 4-Tec Performance
    Replies: 20
    Last Post: 12-06-2010, 07:38 PM
  3. 05 RXT New Member With Mod Questions
    By lateapexRXT in forum 4-Tec Performance
    Replies: 5
    Last Post: 07-29-2008, 01:32 AM
  4. New Member with GP1300R Questions
    By RVCop in forum Yamaha PWC Performance (2-stroke)
    Replies: 13
    Last Post: 12-07-2007, 08:22 AM
  5. New Member With Some Questions :)
    By ADAMBOMB in forum Sea Doo Open Discussion
    Replies: 33
    Last Post: 03-12-2006, 05:08 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
  •