OMGZ Brushless Revo!!! :O Need some advice :D
 

Hi all,

Awesome forum you have here.... I'm new here, so be gentle lol. I've had some experience with nitros and I fly brushless motors in my aircraft so I'm sorta ok in the knowledge side of things (I think). :D

I've spent the last few days reading up on converting nitros to brushless, more specifically Revo 3.3s and I must say, I'm totally confused lol :D

So, here goes with the questions. First up tho, I just want to say thanks to all of you who contribute and share your knowledge; me wub u long time :D

I suppose I should say what I want to achieve and then ask my questions.

I have a Revo 3.3. Just ordered a center diff as well as the rear brake kit, and a set of Tekno sway bars. After doing all that I stumbled across a Revo Brushless conversion and was effectively bitten by the bug.
Now, having just spent up to get my new diff and brakes etc, when I do my conversion, I would just like to use the motor for forward (and maybe reverse if that can be achieved?).
I would like to use the brakes + brake servo to do the actual braking. I figure that this will help keep some of the ware and tear from the tranny, as well as meaning that my brand new brake kit isn't wasted.

1. Is it possible to use the motor for "thrust" and the existing brakes for braking? Is there any point to doing this, or should I just be taking the brakes off and using the motor?

2. Which motor mount should I be going for? So far, I've found the RCM one for $60, and the Tekno one for $150. The Tekno one comes with a battery mount and some other stuff which I have no doubt that I'd find useful. The Tekno mount stresses that only 5mm shaft motors can be used, whereas the RCM one I assume can use whatever size you attach.

3. Whats the deal with the "Elektri Clutch Adapter" that comes with the Tekno kit? Is it needed, or can I just use the stock clutch on the Revo?

4. Since brushless motors can spin forward and backwards (man this is going to sound really dumb lol, but here goes) will I be able to make the Revo go forward as well as backwards, even with the new center diff, if I convert to brushless? As you know, the center diff has the FOC in it, which is why I ask. It would be cool to have reverse available to me, and I can then just disable it when I'm racing.

5. What sort of ESC should I be looking at? I've just ordered a 4600kv Mamba Max motor and ESC combo, so I can steal the ESC from there. It was going to be for one of my 1/10 cars, but this is a much better project IMO. I assume the MM ESC will be on the cheaper end of ESC's so what would be a better choice for ESC?

6. What motor should I get? I assume I can't use the 4600kv Mamba Max motor as it would be too small. I've seen alot of people recommend the Feigao 540 8/9XL in their cheaper setups, and the NEU motors in the better ones.

7. I'm going to need a separate BEC for the servos etc, so what one is recommended? What do the terms mean with regards to BECs ie Switch Mode.

8. I'm totally scared of LiPos. I fly A123 packs in my aircraft, so I was thinking of using these in the revo. I think I'd be aiming for 2x 5S 2300mAh packs in parallel, so a 2S2P pack. That will give me 16.5v nominal voltage, and 4300mAh capacity.
Does anyone know if that man cells will physically fit in the battery holder that comes with the Tekno kit?
Also, is anyone else running A123s with a setup similar to what mine will be with the Mamba Max ESC; and how are the cells doing?


Well, I think I'm all questioned out. Sorry for the Essay tho :D

Thanks in advance :D

Another question I forgot to ask.

I've read that alot of people lock out the 1st gear in the Revo when converted. What is the reason for doing that? Obviously you don't really need it when you have an electric motor, but wouldn't it help to keep it in terms of lesser battery usage and longer run times?

I'm guessing its going to have something to do with keeping the external brakes and stuff, but I will wait for someone who knows more than me to help me out hehe :D

im going to answer as much as i can but i have school rigth now so i have to hurry up!:lol:

WELCOME TO THE FORUMS:yipi:

1you can use the motor for "thrust" and servo for breaks. i beleive this helps the esc out and doesnt make the motor heat up as much. also, will allow more runtime.

2. 5mm shafts are more common in these big units. i would reccomend it also.
and those 2 are the only ones i could think of as far as nice motor mounts go.
you could use an emaxx tranny and use their little motor mount. it makes the truck alot taller though...

3. i believe the elektri clutch is to make it feel sort of like a gas truck.

4 i really dont know either... with the FOC youd think it would not have reverse but idk!

5. go for the mm esc with a Castle creations ubec. and a 8/9 xl like you said. just depends on voltage.

i gotta go to school!

hope i helped a little.!

havea good one:intello:

1. Is it possible to use the motor for "thrust" and the existing brakes for braking? Is there any point to doing this, or should I just be taking the brakes off and using the motor?

- Yes, this is how the tekno kit is setup. The stock brakes, front and rear in your case, will be actuated by the stock throttle brake servo. The tekno kit comes with a mount that removes the stock servo box and just holds the brake servo in front of the motor.

2. Which motor mount should I be going for? So far, I've found the RCM one for $60, and the Tekno one for $150. The Tekno one comes with a battery mount and some other stuff which I have no doubt that I'd find useful. The Tekno mount stresses that only 5mm shaft motors can be used, whereas the RCM one I assume can use whatever size you attach.

- The tekno mount spaces the motor farther backward to make room for the electri clutch. The 5mm shaft is necessary cause the electri clutch has a 5mm hole in it for the shaft.

3. Whats the deal with the "Elektri Clutch Adapter" that comes with the Tekno kit? Is it needed, or can I just use the stock clutch on the Revo?

- You have to use it cause of the spacing issue. I run it in my revo and it works fine.

4. Since brushless motors can spin forward and backwards (man this is going to sound really dumb lol, but here goes) will I be able to make the Revo go forward as well as backwards, even with the new center diff, if I convert to brushless? As you know, the center diff has the FOC in it, which is why I ask. It would be cool to have reverse available to me, and I can then just disable it when I'm racing.

- The only way to maintain reverse in the tekno kit would be to leave the stock, servo actuated reverse. If you install the FOC you will not have reverse.

5. What sort of ESC should I be looking at? I've just ordered a 4600kv Mamba Max motor and ESC combo, so I can steal the ESC from there. It was going to be for one of my 1/10 cars, but this is a much better project IMO. I assume the MM ESC will be on the cheaper end of ESC's so what would be a better choice for ESC?

- The MM is a great esc and works well up to 4s lipo or 5s a123.

6. What motor should I get? I assume I can't use the 4600kv Mamba Max motor as it would be too small. I've seen alot of people recommend the Feigao 540 8/9XL in their cheaper setups, and the NEU motors in the better ones.

- The 9xl should work great with your intended esc and batteries.

7. I'm going to need a separate BEC for the servos etc, so what one is recommended? What do the terms mean with regards to BECs ie Switch Mode.

- You will want to use the castle creations bec, best one out there for your application.

8. I'm totally scared of LiPos. I fly A123 packs in my aircraft, so I was thinking of using these in the revo. I think I'd be aiming for 2x 5S 2300mAh packs in parallel, so a 2S2P pack. That will give me 16.5v nominal voltage, and 4300mAh capacity.
Does anyone know if that man cells will physically fit in the battery holder that comes with the Tekno kit?
Also, is anyone else running A123s with a setup similar to what mine will be with the Mamba Max ESC; and how are the cells doing?

- 5s2p a123 pack is going to be pretty big, not sure if 10 cells will fit on the tekno battery tray. I do not use the a123 cells myself, so someone else should be able to tell you if they will fit.

Hope this helps!

Welcome to the forums!

1) Yes you can retain mechanical brakes. Just disable brakes and reverse in the ESC programming.

2) The mount is up to you. If you don't want to worry about making your own battery tray, then the Tekno one is probably the way to go. If you don't mind modding, the RCM one is nice as well.

3) The clutch system on the Tekno lets you use stock Revo clutchbells. There is quite a bit of debate about what benefit they provide. Personally, I'd lose the clutch and go for a direct pinion on the motor shaft.

4) Yes, you can have forward and reverse, but you will need to do lock the tranny in first or second gear. The OWB on first gear needs to be eliminated to be able to use reverse. There is a sticky in the Revo forum which explains your tranny options and the advantages and disadvantages of each.

5) ESC choice depends a lot on features you want and what you can afford. The MM is a cheap ESC that is good up to 4s lipo, 100A, and is very customizable.

6) MM ESC, 4s Lipo and an 8XL motor is a decent lower priced combo. For a better motor, look at a similar size motor with about the same kv as the 8XL. A Neu 1512 or 1515 series are good choices.

7) Yes, you need an external UBEC. There are lots of choices. Just look for one that can accept the battery voltage you plan to use on the input and can supply the current your servos will need. 3A is a pretty good rating. CC makes a nice one that is programmable. The bottom of this page explains what UBECs are and why they are better.


8) Lipos are fine as long as you protect them from physical harm, use an LVC to prevent over discharge, and pick ones that can supply the current your setup will use. Shoot for at least 120A continuous rating. No, you won't need quite that much, but it's better for the battery to not work them at their max. A123s are fine, they just get kinda heavy. Not sure about the batt mount question, but it's fairly easy to make your own tray if you need to. ZeroPointBug runs A123s IIRC and likes them a lot.

Oh, and I think the Q in your second post in #4 above.

Welcome to the forums Cdis!

Woah, thanks for all the replies guys :D I didn't expect to see so many so soon.

I will do some more research and then come back and ask some more questions if I still need some answered, but I'm fairly sure thats all my questions answered hehe.

Thanks boys :D

Hey there I'm new as well, but I did just finish one..

3. Whats the deal with the "Elektri Clutch Adapter" that comes with the Tekno kit? Is it needed, or can I just use the stock clutch on the Revo?

The Adapter slides over the 5 mm shaft and makes it look like a TRX 3.3 crank shaft, so you can use the stock clutch and bell.. The Tekno motor mount sits further back so you can use the clutch bell....Because it sits further back...if you use the Tekno mount without using the (adapter/clutchbell) and just the regular motor shaft....the shaft is not long enough to mount a pinion on..(or just barley).

Mine is forward only no center diff 2 speed....The Revo tranny has a one way bearing (I'm not sure if the diff eliminates it) The forward only conversion does not eliminate it..So no reverse.........I think ....using the Tekno conversion, the only way to use reverse is to use the stock set up , partly because it uses the stock clutch shoes...They recommend installing the shoes in in the "leading position"...They (the shoes) won't grab as good going in the other direction. I got a 3 shoe set up using no spring........It works awesome......Like a clutch should....

As far as 1st gear / 2nd gear.....I like the 2 speed shift for my driving style....I race on a 60x100 ish track http://106racepark.com/ With my motor set up.....It doesnt' matter performance wise....neu 15151y

Batteries???? I went lipo.....I had to upgrade from my 1200 Nicad packs......But I can tell you.....2 Maxxamps 7.4 6000mah in series , Leaves plenty of room for more....It s NOT protected at all , they use a velcro strap...But a very solid mount.

As for the A123 cells, keep in mind that they are quite a bit larger than your standard sub-c cells. your best bet would be to simply compare the dimensions of the pack you want to build vs the battery box. For my Revo, I just have my a123 packs velcro-strapped to some plexiglass with some grip material under them. Im running A123 cells in my revo, 4s max atm because of no external BEC. The cells are running great, hardly get warm and instant power whenever you want it.

Speaking of A123's and voltages, surely there is a max RPM limit for each individual motor?

The reason I ask is that the kv rating on motors is the number of rotations per minute for 1 volt correct?

So if, for example, I end up getting a Feigao 9XL, which is rated at 1,853kv, and I use my 5S A123 packs which are 16.5v each, the RPM at max volts would be 1853 x 16.5 = 30574.5.

Is it just me or is that INSANE?!? Would that be too much for that motor, or do I have no idea? :D

The Mamba Max combo I'm getting (4600kv) says its alright for 3S lipo, which is 11.1v, but I can't find anywhere the actual stats on the motors, so if anyone has those, please let me know :D 4600 x 11.1 = 51060 RPM. Thats even INSANER!!!

Lol anyway, no more sugar for me, I'm wayyy to excited.

http://www.scriptasylum.com/rc_speed/_data.html

That whole scriptasylum site is pure gold for rc, made by Brian I believe.
and it seems that the maximum rpm for the feigao motor series is around 40k

I think the feigao are rated at 50 000rpm (people have run them faster though), they usually just get hotter if run past
40 000rpm.
Neu 15xx motors are rated at 60 000rpm, plettenburgs I think are 70 000rpm, and I forget what lehners are rated to exactly, but it wasn't less than 60 000.

Another really dumb question :D

With the Tekno mount, I get to use the clutchbell/pinion gear thats already on my Revo with the Elektri-Clutch thing, thereby actually utalising the clutch.

If I go with the RCM mount, I can't use that Elektri-Clutch bell adapter thing can I? If not I guess I'd have to get a pinion gear to fit the motor and mesh it directly onto the Traxxas spur gear right?

If that is the case, I am unsure as to which of the spur gears I would need from teh RCM shop; could someone point me in the correct direction?

Thanks again :D

You will want to use any of the mod1 pinion gears with the rcm motor mount. That mount places the motor closer (front to back) to the spur gear. Stock revo sour gear type is mod1 so any mod1 pinion will mesh properly with it. Keep in mind that most larger motors have 5mm shafts, so make sure you buy a pinion with a 5mm bore. Mike only sells 5mm bore mod1 pinions, and is really the only place to get them. They are all hardened pinions, which does not matter with the plastic spur gear on the revo.