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  1. #1
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    XB21 pad changes

    For those that have ran the newer boats with the smaller lip on the pad what motor height are you running? I learned last week that mine does have the new pad on it. Me and my son fished a tournament from it last week for the first time but I haven't run it hard at all yet. I did feel like it had allot more bow lift than my other one did. The 2010 I had (for a month or so) would almost push the nose down when you stab it from say 30-40mph. This one lifts much quicker. Just trying to gather as much info as I can so when I do get a chance to run it I will have a general idea where to start.
    Thanks

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  3. Member
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    #2
    Interested as well. Us guys with the older pads seem to run 1/2” above max with 8” and 1” above with 10” setback. And personally I prefer a quarter under than height when not trying to run 90

  4. Member
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    #3
    Matt my boat has 9-1/2" of setback and I'm running 1/2"-3/4" above pad. I let water conditions dictate the height more than anything.

  5. Member
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    #4
    Thanks Johnny. I mounted my motor in the middle holes and if I measured it right all the way up on my plate is right at 3/4” above. I think I’m running 8.5” of set back

  6. Member
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    #5
    Matt I have run as high as 5/8” above and posted a good number but it requires more weight to the left. It seems my experience the higher you go the more weight left is needed...

  7. Member
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    #6
    Thanks for the info guys

  8. Member
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    #7
    Matt, what year hull is yours? If you think you have the new lip and it is a stock lip from the mold then most likely you have the new setup which is a set of 4" setback plates and the CMC 5 1/2" plus 1/2" wedges which is 9 1/2" setback. I think 2017 is the start of the new lip from the mold.

    Now if you just bought a pre 2017 hull that had the lip modified by Mr. Allison then yes, you may still have the older 2 1/2" setback plates with the CMC
    2013 Allison XB-21 BasSport Pro
    2016 Mercury Racing 300XS 1.62's

  9. Member
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    #8
    Mine is a 2016. It was Terry's demo that he sold 2 years ago and I bought it from that guy. I asked Terry which pad this one had and he said the new one. He said the mold was changed right before it was made. I know he gets one every year so he could be mistaken on this one.


  10. Member tritontr21's Avatar
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    #9
    Quote Originally Posted by Matt Wayne View Post
    For those that have ran the newer boats with the smaller lip on the pad what motor height are you running? I learned last week that mine does have the new pad on it. Me and my son fished a tournament from it last week for the first time but I haven't run it hard at all yet. I did feel like it had allot more bow lift than my other one did. The 2010 I had (for a month or so) would almost push the nose down when you stab it from say 30-40mph. This one lifts much quicker. Just trying to gather as much info as I can so when I do get a chance to run it I will have a general idea where to start.
    Thanks
    Keep a close eye on water pressure at WOT. I try to keep mine running 20-25 lbs. Pressure will change rapidly once you start to get the motor to high. It is a very fine line!
    Jay McDaniel
    2003 Allison XB21 BasSport Elite 2+2
    2016 Mercury Racing Sport 250 XS

  11. Member
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    #10
    Ok then, I stand corrected. Didn't know it was Terry's boat so then yes it does have the new lip. Curious then why it doesn't have the 4" setback plates. I would highly recommend buying the Allison CMC upgrade kit and have it installed. Save yourself a ton of grief down the road. And you have the HD trim ram too
    2013 Allison XB-21 BasSport Pro
    2016 Mercury Racing 300XS 1.62's

  12. BBC SPONSOR
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    #11
    At 10" back and stock old lip mine will hold 20 psi at 1" above.

    Matt you have 8.5" based off the pic posted above. 10" and that fire brething X should make that hull come to life
    Fastbass Marine LLC
    We specialize in custom marine electronic installations on beautiful Kentucky Lake.

    2013 Allison XB-21 BasSport Pro
    2013 Mercury 3.2 Stroker by DBR

    2012 Bullet 21ss
    2014 Mercury 250 Sport XS


  13. Member
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    #12
    Quote Originally Posted by Tim Powell View Post
    At 10" back and stock old lip mine will hold 20 psi at 1" above.

    Matt you have 8.5" based off the pic posted above. 10" and that fire brething X should make that hull come to life
    Can I be either a dumb smart alec, or a smart alect period. I see 2"+5.5" which would equal 7.5" of setback. Where am I off?

  14. Member
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    #13
    I believe they are 5.5” and the spacer is 2.5”. Normally there is a .5” wedge as well.

  15. Member
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    #14
    There is a wedge in there too but it's black.

  16. Member
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    #15
    yeah, I saw that too. Like Tim stated, go with 10" total with the new lip and yu have the exact setup that is now leaving the factory. Either swap it all out for a JP like Tim has (I forget the name) or replace the 2 1/2" static plates with the new 4" plates from Allison and while your at it install the CMC JP bolt kit.

    OR....leave it all as is and just enjoy what you've got!!! Either way it's an awesome setup that will get you into the 90's anyway.
    2013 Allison XB-21 BasSport Pro
    2016 Mercury Racing 300XS 1.62's

  17. Member
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    #16
    Definitely buy the 4” kit from Allison. Johnny Johnson built his own and did an incredible job on them but said he would have been way ahead to have just bought them from Allison. The time involved and a lot of welding was his issue. I don’t know that the extra bit of speed is worth it to you or not. Most of us spend way too much per mph but it’s why we drive an Allison. ������

  18. Member River Rocket's Avatar
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    #17
    I have run 8, 8.5, 10, 10.5, and 12.5”. I have not seen setback impact top speed to the point that I can say conclusively that the setback did it vs conditions. What I have seen is setback impact the boats ability to carry a load at greater speeds at lower rpm. But tops speeds are all within 0.5mph. My best top speeds came with less setback.
    21' Allison XB-21 ProSport 300XS



  19. Member
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    #18
    river rocket, that is an intersecting statement...."What I have seen is setback impact the boats ability to carry a load at greater speeds at lower rpm." What setbacks offer the best or "worst" in your opinion ability to carry a load??
    2013 Allison XB-21 BasSport Pro
    2016 Mercury Racing 300XS 1.62's

  20. Member River Rocket's Avatar
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    #19
    I’m on my phone and probably should have made that two sentences with better distinction.

    Marginal improvement in load carrying. I run heavier now vs 8” and my numbers remain consistent. Again, we are talking 0.5mph.

    reduction in RPM. For 1.62’s it hasn’t been that big of a deal. My 100mph prop is running lower slip at 12.5” and about 300 rpm lower than it was at 8”. This really helped Jay run high pitched wheels. He has 1.75’s and is often limited by the limiter. He is at 11.5” and no longer hits the limiter even when running 1/2” higher than before. If I had 1.75’s and a 300 this could be useful in helping to buy/run more props that are readily available.

    Some talk about not having to trim as much. I haven’t seen that either. I trim to the exact same numbers as with 8-10.5”.

    My acceleration times from 5-85 have remained consistent as well with all plates.

    My personal take is 8-10 and I wouldn’t spend a lot of money to get 10. Do spacers if you are going that direction.

    Others may may have different results. This has been my take on my boat. It’s a Prosport, so we are talking different rides.
    21' Allison XB-21 ProSport 300XS



  21. Member
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    New Market, Alabama
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    #20
    Matt,

    - Lip was modified on the 16 boat you have now, 4-inch spacers were introduced in 17. I did not have a chance to swap out the spacers before selling her. Bolt pattern for the two different spacers:
    - 4-inch spacer are bolt holes 2, 4 and 7 in the engine mounting plat and counting down from the top
    - 2.5- inch spacer are bolt holes 3, 5 and 8
    - The 4-inch space is 3/4 of an inch higher the 2.5-inch spacer therefore dropping one bolt hole with the 4-inch is the same engine height as the 2.5- inch spacer with different bolt pattern as the bolt holes in the engine mounting plate are 3/4 of an inch apart.
    - I learned this the hard way at 86 miles an hour when I first got the 4-inch spacer and mounted in the same holes as the 2.5 inch spacer in the 3, 5, and 8 bolt positions.
    - Enjoy your new ride

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