MTT EP15 Spektrum 3150KV Motor Tested Losi LMT RTR Monster Truck Motor
Here there it is so. This is the first of two spectrum: 3660 size motors i’m, going to be testing uh, the ones in the son of a digger but we’re going to take the gravedigger one first. So you can see here. We’Ve got the motor out the truck now. The standard pinion is a 14 tooth and you can see there’s space for 16, 15, 14, 13 and 12. here’s, the actual motor itself say 3660 3150 kv and take it out. You just need to remove the well you’d. Actually need to remove the pinion to take the motor out, but obviously i need to do that for the motor test uh, but it’s, literally just four screws to remove the cover which i’ve got there. Three trimming of the bottom bit one to remove the top bit and then the two screws that go into the motor and that’s it i’ve got the motor set up on the tester from the grave digger spectrum motor. The length is 60.25 millimeters exactly the diameter is 36 millimeters bear in mind. It does have some fins here and that is to the outside of the biggest fins um. The shaft length is 18.5 millimeters that’s the length this way and the shaft diameter is five millimeters. Obviously so this is a pretty standard sized motor it’ll fit in a lot of stuff same as you’re getting an armor, uh granite or a big rock or sentine 3s. All the 3s line have a very similar motor to this.
The braiding on the wires is the um cheaper kind of braiding, and not the nice insulation that you get and the wires are very stiff and hard to bend. You can see they’re holding the shape and they’re, not flexible wires, which probably means you can’t cut these wires down shorter uh. You can make them longer, but you can’t make them shorter because i’m guessing these are the winding terminations which are outside of the motor. You can see i’ve got it all hooked up, i’ve already set the um motor tester for a 4 pole. I believe this is a 4 pole motor. What does it say on it? No, it doesn’t it’s made in china it’s branded spectrum using the usual turner g, nanotech 5.6 amp power 2s for the motor tester. So let’s see what the kv really is. You can see we’re at storage charge there, 7.7 volts, we’re, just gon na, go all the way up to maximum it’s. Still going up. This moat has never been wrong. It’S very smooth, very quiet seems a bit all over the place, though i’ll stop it there uh. So you could see it was flicking between 2130 to 2180, which is i mean pretty much bang on what is supposed to be really that’s really good. I don’t know the rating for the current but it’s 3.4 amps at 7.5 volts and it did 23 500 rpm, which is very good. It was very smooth as well so let’s go on and try again i’m going to build up slowly.
This time, though, right so building up slowly on the second test, there we’ve got 31.55. That is almost bang on that’s, really good at 3.3 amps uh, yeah wow does what it says on the tin, very nice uh. So let’s have a look at the noise level. I think the noise level was really good on this, so i’ll just whack it full yeah, so it’s not very smooth starting up. It got to about 81 decibels, but when i’m quiet it seems to be running about 72 yeah 72 73. So that is very, very, very smooth, obviously it’s a fairly low kv motor, so you would expect it to be quite quiet. It seems to be better than most of the surpass hobby motors i’ve tested, so yeah that’s it for this one. This is the motor from the uh lossy lmt grave digger, so we’ll see how consistent they are and do the one in the son of the digger next so now, i’m going to put the motor back in the grave digger just put the pinion back on with A bit of thread lock, you only need a tiny bit of blue thread lock on the pinion gear, because the screw is extremely small, so i’ve got the motor back in now on the 14 to pinion holes, and you can see the mesh looks pretty spot on And they also just had a tiny dab of blue thread lock on as well so next i’m going to put the covers back in and then just plug it in and then it’s good to go again.
So you need to put the top half of the cover on first and then the bottom half goes on second now to put the top half of the cover on glossy. Unfortunately, in their infinite wisdom, uh put this green plastic bar in the way that screw hole, but you can just bend it up out of the way and then you can fit the screw in so then you just put the um lower gear case back on you, Don’T need to do these screws super tight because all four of these screws on the gearbox going into plastic and then, finally, you can just plug your motor back in it’s a little bit tricky to plug them in under there, and you can take the batch tray Off, if you want, but i’ve managed to do it perfectly fine and uh right, let’s move on to the son of a digger motor right, so i’ve got um the motor out the son of a digger. Here you can see it’s not in there uh. Another thing to note with these motors and the lmt is the pinion gears are put on extremely tight so and before you do this, you might need a pinion puller. If you haven’t already got one. I do have a pinion puller, so i didn’t really think of this. But obviously, if you don’t have a pinion puller, you might not want to take uh your pinion gear off and on it’s easier to get back on.
Obviously, because you can just hit it with a piece of water and a mallet to get it on, but pressing it off can be quite difficult. So if, if you haven’t got one of these already uh, you can get one of these. I think mine was from hobbyking for like three pounds or something so it’s a really useful tool, and it does help you get the pinion off if it’s really hard to get off. These um are really really stiff because they put quite a bit of thread lock on the uh, the pinion screw, and i think they put a bit down the pinion and the hole in the pinion as well, so obviously it’s same as the gravedigger other than that. You take case off, take your most screws out, take your pinion off and there is the motor from the son of a digger, obviously exactly the same. But is it really the same we’ll find out in a second? So we have the motor tester on again and obviously same battery and the same but a different motor. If you see what i mean, the other one was from the gravedigger this one’s from the son of a digger, so i haven’t set the poles yet so i need to go on four pole. Oops then we’re going to go to motor kv and i’m going to do a full speed start like last time. I hope this one’s a little better it’s, also quite a bit louder, it’s, making them high pitched whining noise.
This one’s 3200 kv at the moment and you can see it’s using 3.8 amps. This is really interesting. This one’s definitely higher kv, so the guy at the factory who built this one. Obviously, a son of a digger fan boy, so we’ll reset that and build up slowly. This one’s noticeably louder than the warm sound doesn’t sound as smooth yeah. Look at that there you go 3.7 amps 3220 kv i’ll, stop it. There we’ll call it 3220kv and that is very impressive, now uh. To be honest, what should really be the case is that the um on the back of the motor, whatever the rating is, i would say it, should be plus or minus. Maybe a hundred kv. Obviously, more plus is better to be fair, especially if you can keep within your um amps that’s on your spec sheet and it’s, a higher kv. That means you’ve got a more efficient motor, so that is better so yeah this. This motor is actually slightly better than the other one. The other one did still hit its 2150 rated or sorry, 30 150 rated uh, but this one is doing over 3200. So that is pretty nice, as you will probably won’t notice, any difference in uh in real life when you’re actually using the motor. But it is just interesting to see that, even though you’re getting the same motor, you aren’t actually getting the same motor they’re all slightly different as with a lot of things, real cars – and they do have tolerances on these – and this one just happens to be slightly Faster, so let’s see the noise level.
I think this one’s louder Music, it’s interesting, so the decibel meter um says it’s about the same, but it’s definitely a higher pitched wine. From what i’m hearing, that’s, probably from the bearings um i’d, say the other one was a bit smoother to be honest than this one. So yeah there you go it’s another motor test, tuesday we’ve tested two of the exact same motors on the exact same day for the first time. So i hope that was interesting for you, it’s also, the first time we’ve tested a spectrum motor. So there we go.