Another Brushless REVO conversion
 

Hi, my first post here. Every since I got my Revo (nitro) I wanted to convert one to electric power. I have a tricked out E-Maxx but the Revo just handles so much better. I can't wait for Traxxas to make one so I started collecting the parts to convert a nitro Revo to brushless. I finally got enough of the parts to start putting my brushless REVO project together. I was waiting on a custom motor mount (thanks Paul) and it finally arrived this weekend. First, many people who do these conversion use the E-Maxx tranny and motor mounts, I wanted to use the stock Revo tranny with it's auto 2 speed and disk brake. So I needed a special motor mount to use the REVO tranny. I had to machine a stock REVO nitro engine mount to fit onto the new brushless motor mount to give it extra support. The brushless motor puts out a lot of torque and without the extra bracing the chassis flexes way too much.

http://www.pix8.net/pro/pic/2813KUH0k/992475.jpg
Here is my Nitro Revo and the roller chassis I am using for the brushless conversion

http://www.pix8.net/pro/pic/2813KUH0k/992474.jpg
Here is the custom motor mount

http://www.pix8.net/pro/pic/2813KUH0k/992472.jpg
Stock nitro Revo motor mount machined to fit the brushless motor mount


http://www.pix8.net/pro/pic/2813KUH0k/992471.jpg
Bottom view of the motor mount


http://www.pix8.net/pro/pic/2813KUH0k/992473.jpg
Here is a picture of the chassis with the battery trays mounted

I still need make a plate for the receiver and ESC to sit on (waiting on some carbon fiber stock), I have to install the motor, tires, paint the body and hook up the disk brake. Still have a ways to go but I should soon have it ready for a test run. I would also like to mouint the batteries lower, so I may play around with different mounts to get the CG perfect.

that looks very nice. good job on it. you could mount those batteries on the underside of the chassis to get a low CG.

http://www.rc-monster.com/forum/show...?t=4725&page=4

i also did a revo conversion.

you could make a mount plate for the esc and attach it to the rear shock tower where the exhuast hold down attaches.

Welcome to the forums!

Nice job on the conversion!

A suggestion? You could try to move your brake servo further forward and make a new brake linkage. This would give you more room on that side for longer batteries, like Lipos. Even if they are on one side, the balance should still be very close since Lipos are lighter and you have the motor and some of the tranny on the other side. You could mount the receiver and ESC on the same side of the motor and you should be golden. Just my $0.02.

Good job!

Thanks for the tips and suggestions, I appreciate your input. Still a work in progress. Sounds like a very knowledgeble group here, so I am sure I will be updating this thread with many more questions.

Regards

Looks great Shark!

Nice motorholder; looking at the edges, is it lasercutted?

You might need to support the motor to keep it from flexing.

Kyosho batteryholder enable you to hold 7 cells per holder.

Hey Very Nice!!!

Love that motor mount. I was thinking about doing something like that but never got around to it. Do you by any chance have the drawings or a CAD file for a that motor mount? Id love to make one for myself.

The motor mount came from a fellow rc monster poster, his URL is www.eaglesviewaerial.com/products.html and he does fantastic CNC machining in metal and carbon fiber.

When I first got his mount I installed it as is, with none of the stock REVO motor mounts. There was a ton of chassis flex, so I decide I needed to also use the stock nitro motor mount brackets and reinforcement brace. I had to mill the nitro mount flat so I could bolt the brushless mount on top of it. Then I added the extra Traxxas reinforcement plate and bolted everything together. After all of that there was no flex at all, but I agree that a motor brace (rear or mid) would really bulletproof the mounting. I think I can machine a small "U" shaped bracket that can fit under the motor, which I can bolt to the mount. This should provide good mid/rear mount support for the motor.

Nice conversion! I am thinking of doing another, very similar. Stock 2 speed, FOC, center diff w/ rear brakes, and 4S LiPo on the right side with the 2 servos and motor on the other.

Nice conversion

His name is b0gh0s. I was going to have him custom make a motor mount for me for my Revo, but he got too busy. His current mount wouldn't work with the XL motors because they were too long and rear wires would hit the suspension arms due to the mounting height of the motor.

It Lives....

Last night, I mounted the motor and ESC. I moved the battery trays lower, hooked up the brakes and put the tires on. If weather and daylight permit, I will give it a run today. Also, I will try to find my scale and see how heavy it is.

http://www.pix8.net/pro/pic/2813KUH0k/992741.jpg
Motor mounted


http://www.pix8.net/pro/pic/2813KUH0k/992742.jpg
Completed chassis

http://www.pix8.net/pro/pic/2813KUH0k/992743.jpg
Wheels on

http://www.pix8.net/pro/pic/2813KUH0k/992744.jpg
Which one is fastest?

Hard to tell, which hvmaxx is it? they are not known for their brutal strength, but so is nitro.. :p

Looks nice man.

Serum, where could I find some Kyosho batteryholders? I checked around but couldn't find any.

Mike carries them, shoot him an email.

Hey man i was looking at the revo yesterday and i thought good truck but today beings i was so board i looked at each picture very closly for like a minute each and i realized how you mounted the motor. that is so cool and sick. Great job not only on the looks but one the machining and the design to allow you to use the stock motor mount(which is very strong because it has to hold the 3.3 power) using the existing motor mount gives extra stregnth to the motor mount your made nice job!!. i do not have a revo but if i did and i wanted to go electric and i wanted to use the stock revo trans i would want something like that (very clean, sharp, looks prrofessional). Man you should talk to monster mike and see about selling that motor mount because people would buy it NICE Again

blast Off
 

Ok, I took it for a spin today and man does it go. Very strong from a stand still (I forgot how much torque electric motors have, been running nitro's too long). Had to loosen up the slipper a little because I was worried the spur would lose some teeth. The disk brake works great, I had to loosen them up as well (way too strong). It was getting dark and I didn't have anyone around to hold the radar gun so I didn't get any speed readings (coming soon). I did get a chance to weight it on my super duper Oregon Scientific model BWR102 scale. Using generic 3000 mAh batteries the E-Revo weighted in at 10.3 lbs. Without the batteries it weighted 8.8 lbs. My almost bone stock Nitro Revo weighted 8.7 lbs. So not too bad.

You obviously weren't that bored since you didn't read this:

Wow
 

Ok some new pictures. I added a handmade antenna mount, the ESC looked way to vulneraleble so I put the rollbar back on. Since it is heavier I went one spring stiffer front and back.

http://www.pix8.net/pro/pic/2813KUH0k/993077.jpg

http://www.pix8.net/pro/pic/2813KUH0k/993076.jpg

http://www.pix8.net/pro/pic/2813KUH0k/993079.jpg
Normal Pro-line Badland at rest

http://www.pix8.net/pro/pic/2813KUH0k/993078.jpg
Hitting the throttle. Good test of your tire gluing skills.

who makes those decals on the wheels? oh nice conversion too.

when i said i was board(i meant the site did not have any new posts for a while so i decided to take a closer look at the revo pics(without reading all the replies-very stupid of me) i saw the motor mount and then had to comment AFTER i posted my comment i then read where he got it from and i kind of felt bad he already answered it ) SORRY:007:

Radar
 

I was able to make a few runs today before it got too dark. Unfortunetly I only had some 3900 mHa 6 cell Ni-Mh packs and I wasn't even sure they were fully charged. Anyways I made some runs of about 100 feet and the best I could do was 36 mph. I am running a 40T spur and a 15T pinion. I made about 10 full speed runs and the motor and ESC were cool to the touch. Does that speed sound ok with the setup I used? The accelleration was very strong, and the truck was very quick it just seemed that the top speed was a little low.


http://www.pix8.net/pro/pic/2813KUH0k/993505.jpg

http://www.pix8.net/pro/pic/2813KUH0k/993507.jpg



Happy Holidays

If both the motor and ESC were cool, I'd gear up to the 38T spur and see how that does. If everything is still cool, go to the 36T spur.

ive got the 36t spur on a 16t pinion, and after about 20mins of speed runs and off roading it, the esc is warmish to the touch .

Questions
 

Ok, I decided to work on the body and I discovered that the body wouldn't clear the ESC when mounted in the back. So I decided to move the ESC to the right side of the tranny. Body now fits, ESC proctected. Originally I wanted the CG centered left to right and slightly bias toward the rear. With the batteries mounted side saddle there is more weight on the left side (battery plus motor on left, battery, ESC, receiver on right). But, mounted side saddle the batteries are very low which lowers the CG, and theroetically should make it corner better. I decided to experiment and I mounted a carbon fiber plate on top of the rear shocks, using some alloy brackets and the rear body mount. On this I added the left side battery, so I had a battery on top and one on the right side. In this configuration the CG was almost perfectly balanced left to right with a rear bias, just what I wanted. But with one battery mounted on top this moved the CG higher. The top configuration I assume would be similar to a Revo conversion using the E-Maxx tranny with the motor mounted on top. The utimate test I guess would be to try both configurations on the track and see which works out better. I appreciate your feedback and suggestions.



http://www.pix8.net/pro/pic/2813KUH0k/993529.jpg
Body trimmed and mounted.

http://www.pix8.net/pro/pic/2813KUH0k/993530.jpg
ESC moved.


http://www.pix8.net/pro/pic/2813KUH0k/993531.jpg
CF top plate mounted.

http://www.pix8.net/pro/pic/2813KUH0k/993528.jpg
Pack mounted on top.

http://www.pix8.net/pro/pic/2813KUH0k/993532.jpg
Side view.




Happy Holidays.

Why do you put the batteries further to the rear? It's a heck of a mass, sitting relative high and far to the rear.

Gearing
 

Regarding the gearing, I have a problem. Using the special motor mount I can only use the 40T spur and 15T pinion. I cannot move the mount any further to the right to adjust for smaller Spurs or pinions. This is because I am using the Revo Mod 1 gears. The mount was originally designed to use the stock 48pitch gears off an E-Maxx. I like the Mod 1's because they are stronger. I guess I could drill and re-tap some new holes to allow me more adjustment, but there isn't much selection in Mod 1 pinions with a 3mm bore hole and the largest spur traxxas makes for the Revo is a 40. I could probably mod a truggy spur to fit, but that would be more work. And on the track I race on, 36 mph top speed and super strong accelleration works out perfectly.

Serum, It's just that with a battery and motor on one side and a single battery on the other the CG is heavily bias to the side with the battery and motor. I am worried that the handling will be adversly impacted. The track where I race has several double and triple jumps and the thought of a left side heavy 10.5 pound MT hitting those jumps at speed could be trouble. I imagine it would start pulling left after each jump. I agree that with the batteries sitting so far back and high that it seems like it probably won't handle very well. But Like I said, It will be easy for me to move the batteries around to see how the different battery configurations effect the handling. I won't be able to run it in the dirt for a while (Holidays). Thanks for the feedback.

Maybe "machine" out the mesh slots on the mount for more range??

BTW: The person who made your mount actually uses 32p gears IIRC. Maybe see if the Jato 54T spur fits there? It might not since it is kinda large in diameter compared to the Mod1 40T, but might fit since you have the spur spacer...

BrianG, as you may already know the 40T mod 1 spur comes very close to the chassis. There really isn't much room for a larger Mod 1 spur gear. With a 48P spur you can probably squeeze in a slightly bigger (numerically more teeth) gear because they are physicaly smaller. I may go that route eventually, if track testing shows I need the gear (lower) change. The slots on the mount are pretty much as close to the edges as you could make them. As I said you would have to drill and tap new screw holes to be able to use smaller Mod 1 pinion/spur gears. The accelleration is fine, I was just a little worried about the top speed, which would require a smaller spur/pinion. I need to radar my nitro Revo to see how they compare, I don't trust the Traxxas advertisments (40+ mph). Also, I don't think the gear box was shifting into 2nd gear. So I need to adjust the transmission shift point to make it shift sooner, to see if this makes a differnce. Overall I am very happy with the conversion, because with one as complicated as this it normally takes several prototypes to get it perfect. And there is a lot of fine tuning that still needs to be done (gearing, close ratio gears, shifting adjustment, more powerful batteries, different tires, battery placement, CG adjustments, etc.). This will require track time and that will have to wait until the new year..


Regards

Yeah, I knew the spur gets pretty close, but wasn't sure if that spur spacer piece you got as part of the conversion kit added enough space to allow a little more clearance for larger spurs.

Since you're still using the two-speed tranny, you could gear up by simply getting a larger pinion. The thing is, to get the pinion to physically reach the spur with that mount, the pinion will probably need to be big.

Don't forget, there are three 2nd gear options, close, normal, and wide ratios, which you can use to get the gearing you want.

BrianG, yeah I have the close ratio gear set. So I have several setups to test out. Std gearing and close ratrio internally, I have a 36, 38 and 40T mod 1 spurs, I have a 13 and 15T mod 1 pinions and I could use the adpater and use 48P Spurs and pinions. But I really like the mod 1 gears. I also want to get the wide ratio gear set as well. How is your brushless Revo working out? Have you tried Lipo's yet?

No, no Lipos, still 14 GP3300 cells. I love my Revo. I locked it into second gear though so I could use reverse and motor brake. I'm also using the wide ratio gear set. BTW: first gear in each set is the same, it's only 2nd gear that changes. I don't know how fast it is, but is plenty fast for the small LHS track...

After playing for some time with REVO adapters found out that rear motor support is the most important thing.

I like this setup, as being close to ideal

Artur

My current mounts make the motor sit so low, that it hangs on the bottom of the L plate. Works like a charm. Low CG and a good support.

Personally, I like the first one better. It uses 6 screws to hold the mount down. The second one relies on only 4 screws into the relatively weak stock motor mount. I do like the rear support though, but it seems it only works for a certain motor length.

(@GriffinRU: The first setup is what I PM'd you about)

To support the rear of the motor in my current design, I just wedged a thick piece of rubbin between the underside of the motor and the mount. Not the prettiest, but it worked. :)

This one right?

Artur

Yup, that's the one...

Although, if it's easier, I don't think I need the pivoting base since the motor itself can be adjusted by the slots...

Any thoughts on this support?

Artur

P.S. flip support 180 to match mounting holes...

Yeah, that looks like it could work nicely! :027: The only thing to remember is to adjust the support when you adjust the mesh, but that's no biggie. I'd probably add a thin layer of foam or some type of cushion to keep from scratching the motor, but that's easy to do.

You haven't by any chance made a stronger mount did you? I mean the longer parts that go over to the bulkhead ends and supports the stock pivot point. It seems to be made of pot-metal or something.