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Thread: Help choosing a larger prop for my impulse 31 (v3)

  1. #1

    Default Help choosing a larger prop for my impulse 31 (v3)

    Hey guys I just recently bought an impulse 32 v3, the boat runs great and I have no comlaints other than it’s nit fast enough for me.

    I’m running 2x 6s 4800mah compact Lipos in Parellel which I know is a lot of weight but they are no larger than a typical 4s 5000mah pack. It’s what I had when I bought the boat so that’s what iv been using.

    I was wondering if I could get away with using a larger prop to gain more speed. I would like to be running around 60mph but right now I’m only hitting 43mph max. Part of it is due to the heavy battery’s the other part is due to my trim tabs and drive strut I’m sure.

    I recently raised the drive strut slightly and also raised the trim tabs so that the boat gets some better lift out of the water and doesn’t ride so wet. I’m hoping this gets me in the 50mph range. So really I’m looking for a prop that will safely give me an extra 10mph at least so I can achieve 60mph (ish) speeds with the boat.

    Currently my motor temps are between 115-139 degrees Fahrenheit depending on how I run it, and my esc temps are only around 110-115 Degrees Fahrenheit so I feel as tho I have some head room for a larger prop?

    You guys tell me!

    Thanks in advance!

  2. #2


    maybe you should mention what size prop your running now. also you have some heat in the motor and esc. you might need to trim the hull out better by removing 1 x 6s pack and set c.o.g. correct.

  3. #3


    You don’t say how long you run to obtain those temps, 139*F on the motor is getting pretty warm. Raising the prop settles the hull into the water, increasing drag.

    Have you tried searching these threads and posting there?

    ERROR 604 - Caller's Buffer Is Too Small
    1. Ensure that your port is not configured to a mini plug
    2. If you are still having problems, contact someone

  4. #4


    I am using the stock prop. I would have mentioned the prop type had it been an aftermarket.

    The motor and esc and wire temps are after a 88 degree day of me pounding on the boat pretty hard. Lots of wide open throttle so those temps aren’t bad at all IMO

    Also as I said I need to tune the boat still as it runs pretty wet currently... I already have the Lipos as far toward the back as they can possibly get (I thought I mentioned this too)

    As I was saying my next steps are going to be adjusting the drive strut as well as the trim pads to allow the boat to come out of the water a bit more which will allow the motor and esc temps to run just that much cooler.

    I feel I could get away with a slightly larger prop. I’m asking you guys what you think and what would be the next size up from stock that I could go to gain a little more top end out of my boat.

    Also yes I have seen those threads and I have done a ton of reading about prop size and and what not on this boat, but most these threads are about going with a smaller prop because of a higher KV motor swap..

    I’m looking to keep the same motor (if possible) and go with a larger prop instead since I feel that I have a little headroom to do so (depending on how much bigger the next prop size is from stock)


  5. #5


    Yes your right, I meant to say lower my strut to lower the prop.. I didn’t mean to say raise..

    I feel lowering my strut will pull the boat even more out of the water which should keep my motor around 115 degrees even on those real hot days.

    I plan on lowering the strut 1/8” at a time. As I said I already found my COG with my Lipos which is all the way to the rear (being that they are a bit heavier than your typical 2x3s setup. But I may have to find my COG again once I lower my strut 1/8”.

    I am going to do some testing with it tommarrow with the strut 1/8” lower. Keeping the turn Fins, pads, and Lipos in the same exact position to start out to see what kind of affect I get out of just lowering the strut some.

    It shouldn’t take too much as the boat wasn’t running horrible but deffeinetly did seem like it ran a little wet and that was mostly due to the heavier battery’s I’m sure.

  6. #6


    You never mentioned your battery position in your first post, we aren’t mind readers ��. What is the CG? It doesn’t matter where your batteries are, what matters is the CG position in %.

    We asked for your run time, but no answer.

    You say up is down, etc. no wonder we are having difficulty in helping you. We want to help, but you have to help us understand your situation first.

    ERROR 604 - Caller's Buffer Is Too Small
    1. Ensure that your port is not configured to a mini plug
    2. If you are still having problems, contact someone



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