Outboard motor choice

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  • kendt
    Senior Member
    • Jul 2011
    • 557

    #1

    Outboard motor choice

    I have a 7.5 bullet drive on order. I now need to chose the motor to go with it. What are the best choices for a 35"tunnel for a good combination of top speed and run times??
  • siberianhusky
    Fast Electric Addict!
    • Dec 2009
    • 2187

    #2
    Over on International waters forum there is a current discussion on 6s setups for tunnels, lots of opinions going on, Scorpion outrunners, Leopard 4082's Castle 1521's.
    No experience with 6s setups so I have no valid opinion, been following this thread though.
    Just a feeler thread to see what people might run with a 6s OBT. Hull is a Vision 40. MGM 250amp (3-8s) ESC Lawless 7.5 lower modified my Kris Flynn. 6s/1p lipo setup... My motors that i have for testing are. 1527/1y 1527/1.5d 1521/1y. Open for other motors other than Neu. Needs to run...

    Might have something new to test next time out , this one will win in a collision! To be weird I might just clear coat it as it sits. The Rat Boat.
    If my boats upside down then who owns the one I thought I was driving the last two laps?

    Comment

    • kendt
      Senior Member
      • Jul 2011
      • 557

      #3
      Ya there is some good info there. Too freakin bad I cant see any of the setups. Ive been trying for two f'n weeks to register there with no sucess. Even emailed the moderator and got no reply

      Comment

      • kendt
        Senior Member
        • Jul 2011
        • 557

        #4
        ok a castle 1515 2650kv brand new for 119.00 was just too good to pass up...lol

        Comment

        • Darin Jordan
          Fast Electric Addict!
          • Apr 2007
          • 8335

          #5
          Originally posted by kendt
          ok a castle 1515 2650kv brand new for 119.00 was just too good to pass up...lol
          That is way, Way, WAY too much KV for even most 4S setups... AND, the motor is "small" for a 35" boat... not enough iron involved to absorb the heat generated by pushing something that big...

          If you are going to be building a 6S sized Outboard, which you are... you want to look at something in the 1500KV range at best... I'd even shoot for 1300-1400, and something with MASS to it, like a Scorpion outrunner or one of the Leopards, etc... Something OTHER than a 36-ish mm diameter motor...

          Just my opinion....
          Darin E. Jordan - Renton, WA
          "Self-proclaimed skill-less leader in the hobby."

          Comment

          • kendt
            Senior Member
            • Jul 2011
            • 557

            #6
            Wow I just saw a video of a guy using the same motor on a 36in wood tunnel, 5s and the thing was flying.

            Comment

            • bbill1
              Tunnelboat Mafia Member
              • Feb 2011
              • 123

              #7
              Originally posted by kendt
              Wow I just saw a video of a guy using the same motor on a 36in wood tunnel, 5s and the thing was flying.
              Yeah but are trying to race it, just play around, or do saw runs and bring it right back in in 30 seconds...
              Current IMPBA P-O/B Tunnel SAW record holder with avg time of 3.358 seconds @ 67.004 MPH.
              Owner Worlds fastest record setting Lynx with average time of 3.287 seconds @ 68.451 MPH.

              Smocktura Props!

              Comment

              • kendt
                Senior Member
                • Jul 2011
                • 557

                #8
                Well i wont be racing it so thats not a worry. I wanted to go down to 4s because 6s batteries are just too much money. If it doesnt work out ill sell it and try something else. for 119.00 its not a huge loss.

                Comment

                • bbill1
                  Tunnelboat Mafia Member
                  • Feb 2011
                  • 123

                  #9
                  Originally posted by kendt
                  Well i wont be racing it so thats not a worry. I wanted to go down to 4s because 6s batteries are just too much money. If it doesnt work out ill sell it and try something else. for 119.00 its not a huge loss.
                  You misunderstand my statement. With a 2650kv motor, you won't be running it more than about two minutes tops before you start burning up stuff. And that is on 4s. That is basically a SAW motor.

                  If it doesnt work out ill sell it and try something else.
                  If it doesn't work out you probably won't be able to sell it. cause it or the esc, or both will be trashed.
                  Current IMPBA P-O/B Tunnel SAW record holder with avg time of 3.358 seconds @ 67.004 MPH.
                  Owner Worlds fastest record setting Lynx with average time of 3.287 seconds @ 68.451 MPH.

                  Smocktura Props!

                  Comment

                  • kendt
                    Senior Member
                    • Jul 2011
                    • 557

                    #10
                    Hmm well thats not good...lol would it be the same case with that motor in a 32 in mono or worse??

                    Comment

                    • kendt
                      Senior Member
                      • Jul 2011
                      • 557

                      #11
                      I sent a message to the seller to ask if I can cancel. Hopefully he'll play nice...lol

                      Comment

                      • Darin Jordan
                        Fast Electric Addict!
                        • Apr 2007
                        • 8335

                        #12
                        Or... you can just run it on 3S... It's perfect for that... 3S2P would be the same number of cells purchased as 6S1P, and, while you would be drawing more amps, you'd have longer runtime... Would need a GOOD ESC, however... most likely.

                        You would REALLY be better of with the RIGHT motor in the 1300-1400 KV range on 6s, or an 1800-2200 KV motor on 4S...
                        Darin E. Jordan - Renton, WA
                        "Self-proclaimed skill-less leader in the hobby."

                        Comment

                        • kendt
                          Senior Member
                          • Jul 2011
                          • 557

                          #13
                          Well thats good to know. If i am unable to cancel I will go that route. The hobbywing 180 would do the trick wouldn't it??

                          Comment

                          • lohring
                            Senior Member
                            • Jun 2011
                            • 183

                            #14
                            From this thread on International Waters:

                            We are looking for a low cost replacement for 7.5 nitro engines. The first test was on Leecraft XT-460 tunnels. After some trials with inexpensive motors that didn't hold up we settled on:

                            Scorpion HK 4025 1100 KV motor http://www.innov8tiv...products_id=569
                            Turnigy 180 amp speed control http://www.hobbyking...?idProduct=8937
                            6S 5000 40 or 45C batteries http://www.hobbyking...idProduct=14616
                            Hyperformance 7.5 outboard conversion kit http://hyperprod.biz...ersion_kit.html

                            That power plant costs around $400 with the motor at $160. Still, the cost is in line with nitro power heads. We used an old K&B lower unit. The performance of Brian's boat is better than a mod engine powered XT-460 with both electric and nitro boats running an Octura 1450 prop. You just need to run the prop a lot shallower than with a nitro engine. Bigger props torque the sponson into the water, flipping the boat. Outrunner motors worried us since they aren't as easy to water cool as inrunners, but that doesn't seem to be a problem with outboards. The next test will be an inboard setup in a Sport 40.

                            Lohring Miller

                            Comment

                            • kendt
                              Senior Member
                              • Jul 2011
                              • 557

                              #15
                              I did read that post. Isn't the 1100kv a bit low. Im no expert thats for sure it just seems most recommend in the 14-1600kv range.

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