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  1. #1
    Haven't fallen yet. MJE's Avatar
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    my slightly modded and highly polished SS intake grates

    Well I should say "grate"...I haven't started on the 2nd one...I need a more aggressive 2" cookie to speed up the process. I'm happy with the results so far. I also bolted the pump shoe to the ride plate outside of the ski and ground it then polished it per the fountain boys recommendation. Pics don't really do it justice but I'll post a few.

    I started out by taking the front piece of the intake grate and cutting/tapering the metal back about an inch and a half so there is a smooth passage for the water to flow...it resulted in nearly a blades edge at the front. I used a 120 grit 2" cookie to do most of the aggressive cutting along with a "brown" 2" cookie most of the time...then red and finally blue to polish it up. I'm dealing with a piece of shit air compressor though which has no water separator and it drips onto the cookies which leaves me with a blotchy looking but super smooth grate.

    I made a few measurements of the grate and found imperfections in the mold that were obviously carried over from the R&D grate that was cloned...one thing I'd like to note is the fact that the larger scoop was nearly 1/8" longer on one side than the other...a bit of filing and then tapering took care of that. If I left that alone it would definitely result in me pulling to one direction especially at higher speeds.

    I then proceeded to put razor blade edges on all of the leading edges of the grate to reduce drag. I have to say I never really paid attention to how much potential is really on the bottom of our skis and I'm glad I put the time in to do it right.

    The trailing edge of the rear of the intake grate was over an 1/8th of an inch too high and I used a carbide high speed bit to do a bit of the removal followed by my reduction process in the grits used to provide a shine. I didn't really do a single thing to the pump shoe internal areas because they are thin.

    I haven't done razor-like edges or tapering to the 2 bars...yet. I'm just not sure if its really going to make that much of a difference considering the tiny surface area. I'll take more pics as I go along.

    Before you all say it...I already had pump plug kits installed but I removed them and am going to fill the holes with a liquid epoxy...most likely G/Flex by West Systems. I should have my 1390 back this week from Lowell and hopefully in the next week and a half after its broken in I can give you some results.

    My apologies for being long winded...just wanted to be descriptive.
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  2. #2
    Looks nice Mike.. Takes a long time to do that, i know.. Cant believe how hard that stuff is..

  3. #3
    Haven't fallen yet. MJE's Avatar
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    that was over 5 days of grinding and polishing...well worth it though considering I am making a smooth hull and nearly eliminating drag.

  4. #4
    All hail the Chief! fullboogie's Avatar
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    Looks good. I think you'll find that knife edging the leading edges give you nothing, and may in fact hurt a little. We've tried that on the old grates several times. Think about an airplane wing - rounded in front, knife edge in back.

  5. #5
    Quote Originally Posted by fullboogie View Post
    Looks good. I think you'll find that knife edging the leading edges give you nothing, and may in fact hurt a little. We've tried that on the old grates several times. Think about an airplane wing - rounded in front, knife edge in back.
    Ive often wondered about that, but never did a back to back...These SS grates are pretty sharp on the leading edges, much more than the R&D grates are. Wasnt sure if that was a little of the Tommy Jordan influence on these or just an unintentional difference in the casting..

  6. #6
    All hail the Chief! fullboogie's Avatar
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    Ross - I don't think there's much difference in anything we do to these grates. I've worked an 800 grate to death with polishing, profiling, etc. and it runs a few tenths slower than an untouched grate. And then, I've worked a grate and it picks up a few tenths.

    But I do know that knife edging does, in fact, slow it down a tad. I tested this back to back a few years ago on a 1200 and an 800 grate. I assume the same applies to the SS grate. Personally, I would only remove/fix any obvious casting flaws or misalignments and be done with it. There's just not much to be had in profiling a grate, especially these hard-ass SS grates.

  7. #7
    Haven't fallen yet. MJE's Avatar
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    Quote Originally Posted by fullboogie View Post
    Looks good. I think you'll find that knife edging the leading edges give you nothing, and may in fact hurt a little. We've tried that on the old grates several times. Think about an airplane wing - rounded in front, knife edge in back.
    one thing I paid particular attention to was this "edge"...I ended up tapering it from the top side ONLY so I don't create a hump that may cause issues. Hard to explain and I doubt my camera has the capability of producing a high quality image to really show what im talking about. I did the same type of edge on my aluminum intake grates on their 2nd season and I was very happy with the hook-up.

  8. #8
    All hail the Chief! fullboogie's Avatar
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    MJE - don't get me wrong, the work you did was very nice. Didn't mean any of this as a criticism. Just reporting what we discovered in testing.

  9. #9
    Haven't fallen yet. MJE's Avatar
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    criticism is appreciated tbh...

    I'd have never gotten these skis to the point they are at without the wonderful minds of the GH forum members!!!

    As far as top speed it really doesn't matter to me if i lose a tiny bit of top end...in the conditions i ride in i prefer something that stays hooked up, no cavitation etc. Hopefully thursday night I'll have the first ski back from the painter and be able to bolt things up and do my final grind/polish to make sure every part has a seamless transition from one to the next.

    -Mike

  10. #10
    One day at a time..... N8R's Avatar
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    the leading edges and the bars are thinner on purpose, due to the 800 grate having a shitty holeshot they gave it more water to help without costing alot on top.. more water in the grate = less speed,,, less water in grate= more top speed but, shitty holeshot... cant have one without sacrafising the other

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