Planning Revo V2, to use stock tranny, C. diff and RCM motor mount
 

I am looking to start a V2 revo conversion using after doing an Emaxx tranny conversion last year. After a few little tweaks to the tranny, the setup has been pretty bullet-proof and I've been extremely happy with it. The area for improvement I'm looking for is the addition of a center diff. The 8Xl motor I have now just puts out too much TQ (esp on 5S) to put all that power down. While I'm at it, I'm aiming for manual brakes at the expense of reverse. I've also gone entirely to lipos now, so I don't need to fit all those NIMH cells on both sides, so going to a single batt tray will keep things easy. Plus the new RCM 1/8th Diffs are calling, so I'm looking at setting up one nice truck. :)

Before I get started I'd like to gather some information and opinions here.

Biggest question is what all is needed to get the stock Revo tranny ready? I still have the 2.5 tranny from the last conversion, so that will be the start. I will be adding the centerdiff, FOC, rear brakes, and prob the wide ratio kit w/ buggy diffs to get the gearing right (thanks to Brian's calc, swapping the gearing around to find ~previous ratio was easy.)

My understanding is that locking the oneway bearing should not be an issue since I am not going to have reverse nor engine braking, yes? Basically the BL motor will be a "direct" replacement for the nitro motor.

It seems the stock tranny is very tough and smooth, so no metal gears are needed. Is this the experience of those that have used the stocker (either BL or a Big Block nitro or equiv.)?

Lastly, how is the clearance w/ the rear arms using the RCM mount and an XL motor. should be tight but ok?

Sounds like a plan! Do you still want the two speed tranny? Because unless you lock it, it will still shift. You could adjust the shift point until it is basically locked into first or second, but not as solid IMO. As a plus, if you remove first gear, it lightens up the tranny a little, and if you decide to later use reverse and/or motor braking, the tranny will be already capable of it.

The stock tranny is pretty tough and can stand up to BL quite well. The only thing I have broken is one of the little pins securing a gear to the shaft (the intermediate gear in front of second gear).

The end of an XL can does clear the arms, but you'll have to orient the motor so the wires will clear. If you look at my revo pics ("My BL Conversions" link in my sig), you can see how my wires sit. I also mounted a little L bracket to support the wires coming out of the motor. It was mounted using the same screw that holds the rear rocker arm in place, so no big deal there.

If you go with a center diff, you are going to want some pretty thick fluid. I don't know what weight is currently in mine (it's a custom 8th scale diff I got from Squee) but it diffs out easily. I'm thinking somewhere around 300-500k.

2spd? No! Who needs a stinking 2spd w/ BL power? :) 1st will go going out too. The only advantage I see of keeping the 2spd is to be able to overgear a bit for some top end, but I don't think it will be needed, plus I'd rather trade off that for better reliability.

Did you do anything to upgrade that pin, or is it just an expected casualty?

I did see pics of the motors mounted, and I did notice the wires on the top. I couldn't tell from the pics is if the arms would touch the wires when the suspension was fully compressed. Looks like it will clear, so that is good.

So now goes the long process of ordering parts, waiting for backordered stuff, and getting stuff in. Good thing is 1.) I have a truck to play with in the meantime, 2. I should be able to get most of everything from Mike. :)

I think I used the stub axle pin from a Jato (the one that holds the driveshaft to the stub axle). IIRC, it's black instead of chrome so I thought it might be a little stronger. No problems thus far, but even with the old style pin, it took several days' worth of running before it snapped.

And yup, the arms do clear even at max suspension compression.

i would go with 500k, i have one in my erevo and its got 300k and it still diffs out badly with a hvmaxx 4.5, so go for the thick stuff, imo

Plans are still alive! I've been busy acquiring the parts. I have the tranny w/ CD and rear brake and a revo roller to go along with it. I decided to go with a 3.3 instead of the 2.5 chassis that came with the roller and I'll pick that up Mon from the LHS. Recent news of the pending release of the MMM has got me excited. I would really like to go 6S lipo and ~12XL motor. Should be powerful, smooth and cool running. Now how to fit everything is a different matter... We'll have to see what the dimensions are.

Pics of Mike's pretty mount in the chassis to keep things interesting in the meantime:

http://i7.photobucket.com/albums/y25...4/7f708e46.jpg
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Cool project Finnster.

You can have Mike make you a batterytray machined from some plastic.!

Is that going to be in the store? I just made a polycarbonate one and I don't really like how it came out.

It would't surprise me if Mike puts them in store sooner or later!

Finnster, I am going to be attempting a similiar conversion on a used revo I recently bought.

I have been struggling with how to set up the tranny though and wonder how you plan to be able to use a single channel on the reciever to make your esc work when you pull the throttle trigger back and yet make it controll the servo for mechanical brakes when you push the trigger forward? I can't figure out how to make that work and I can't seem to find any info on it or even a different way to do it.

I would really like to retain the mechanical reverse and brakes on my revo tranny so that I can keep the two speed functional but I am stuck on the issue I asked about previously, how do you controll two different items with a single channel on the reciever?

Welcome to the forum.

Quite a familiar username you picked.

You use a Y cable on channel two to make it happen; on 1 side you hook up the esc, and on the other the braking servo.

thanks:) yeah I figured I would try my question here since this forum seems to have a lot more folks that have done the revo conversions.

My problem with a y harness is that I'm using a hvmaxx 6.5 setup for it and there is no way to defeat the motor braking on the hvmaxx esc (that I can find anyway) so if I did the y harness it would apply the motor brake and the mechanical brakes at the same time.

Now that I think about it though, would that even be a problem?.....I read somewhere in here that the two speed in the revo tranny has a one way bearing so does that mean that even though the motor is braking it would only stop the rotor on the motor while the tranny would continue spinning freely allowing the mechanical brake to do all the work? Is that how it would work? if so is there any harm to the motor in doing it that way?

Yeppers, in addition you want to make sure you have the reverse disabled on the esc obviously. :)

Now the (mechanical) reverse is a diff story. You will need a 3rd channel for that, but they are notoriously weak and heavy, so most do the FOC (forward only.) There is not a way to have motor reverse and mech brakes either, unless you tried brakes on a 3rd channel.

I am curious how much the transmission would weight with the FOC? got a scale Finnster?

I have a very fine digi scale. :) I actually have two trannies, one stock 2.5 and a CD/rear brake (which includes FOC by default.) I'll get some weights tonite. IIRC, after I got done with my Emaxx SS tranny on V1, I think I got it down to 180g. I'll find my notes or reweigh it when I pull it out for a little service. The Revo I think will be more, but the brakes do make up some weight, 20g maybe? We'll see.

I have most of my parts now. Its just a mtter of putting everything together. The roller I got was a used nitro, and its dirty and smelly, so I'm taking my time going thru it, getting as much as the oil and grime off, going thru all the bearings, re-oiling, and basically doing a whole tear-down. My V1 was a truck that was bascially a new 2.5. Guy had the motor frag during break-in, got pissed and sold it. Got a barely used truck for 1/2 price :) What a difference in cleanliness. V1 has barely seen nitro, so no dirt sticks, the V2 roller is lightly/mod used w/ nitro and there is sticky oil all over every surface. What a pain. Yuk.

Since I have a Revo to play with, I'm taking my time on this one. I'm actually going to be Chester NY on memorial day, so was hoping to make it to the Barn, but I don't see that happening. :( I could bring my v1, but its very much setup as a basher, and since I've never raced, it would be pretty ugly. I don't even have good racing tires. Is there a RCM bash this year? I'd really like to make it to there. Hopefully either the Tekin MT or MMM will be out by then as well.

Work has been moving along. Got the basic chassis all back together. Got (one of two) trannies modded, and got the bottom plate for the batt/esc tray completed and mounted. Still have some work on the batt tray. Needs straps and some guardrails. Then just need to mount electronics and then I will be good to go. I'm waiting on 500K oil for CD, so I got an FOC for the stock 2.5 tranny and have that mounted. Weight was 220g IIRC, but got excited and didn't write it down. I'll get better weights later. Pics:

http://i7.photobucket.com/albums/y25...4/ff68c458.jpg
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Did the 2nd gear locker BrianG style. I notched the clutch slightly to fit the 4mm screws, and tapped the 2nd gear as well. I lined up the clutch so that the drive arm is engaged, and the notches hold it solid as well. I'm sure I could have used just two screws, but no biggie. I made the notch in the clutch so that the arm could not disengage even it wanted to. Its def solid. I had socket head screws, but button heads would work as well. The screws must be 4x10mm tho. Any longer and it comes out the back and into the drive gear (not shown). I have man brakes, but this way I can simply switch back and forth between motor brake&reverse or man brakes and Fwd only. May just keep the 2nd tranny so I have one with a CD/rear brake, the other with a solid axle and possibility of reverse. Its easy to swap the two out.

Nice job so far!

you do know thaty with an electric motor you would still have reverse even tho you have the CD. so i would just keep the CD trans and sell the other one, unless you are gonna switch from nitro to electric. i also ground down the peice that holds the little brake arm thin from the front of the case. it looks better IMHO

Yeah, there would be nothing stopping running the CD in the reverse direction. I would have to disable the man brakes tho, and I'm not sure how motor braking w/ a CD would be. Seems like it would get wierdly balanced pretty unpredictable, but then again I've never tried it. The big diff in the trannies would be if I will like the CD or not, or at least having the option to quickly change between a solid center & CD. Aside from the small notches, everything is reversable should I decide to sell it or not. Perhaps someone would even want a locked tranny for their conversion? :) Either way, I have two clutches, one is modded, and prob will stay that way for a while until I see how it drives and what I want to do w/ it.

Like me if you would so happen to want to sell it!!

I am trying to sell stuff to get my e-revo finished. It is taking forever LOL. I have taken a lot of notes from you guys

Almost finished!
 

Pretty much wrapped up the batt mount and esc tray. Everything is together, so I threw some batts in and took for a drive. Very pleased with results. The truck plants and takes off with very little wheelie action (which was one of the main goals of this build.) I can also accel a lot harder w/o fear of the backflips.

I'm still waiting on some parts, so I mounted the Rx temp on the st servo and made up a makeshift antenna mount. The ESC is held down well w/ HD velcro, but I want to work on getting this a little straiter and more secure. I have the solid axel tranny in now as well, as I'm still waiting on 500K oil from AMain hobbies. I also have a new Futaba 3PM coming, so I will figure out a better mount and hopefully be able to use the BEC w/o glitches (still using RX pack.) Also have some Ti tie rods/ hinge pins, and some red tubes for the pushrods on order as well.

I still have stock diffs, as I've laid out quite a bit for some goodies on the side. My other truck lasted months on the stockers, but I think I already killed the rear. I was launching it really hard in the street testing it, and now its clicking... 1/8s may have to go in as well... Going to try a stocker in the interim as I've done the wallet some damage, so those may have to wait.

http://i7.photobucket.com/albums/y25...4/05fb4046.jpg
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Need to clean up some wires as well w/ the batts. Everything is close now, so I can trim things down. Some other wiring may change w/ new Rx and BEC. Enjoy in the meantime. :)

That's one loooong sucker with the 3.3 chassis and the setback arms.. :)

Looks like it has a nice low CG though!

man that looks awesome. i never really liked that motor mount but i beleve its growing on me, except for the price tag. kinda hard to get quality stuff with a low budjet

Very nice. But, that thing looks really long!! lol Looks like you were able to fit everything on it pretty easily with some room to spare. Nice job.

Alright some more updates. :) Got the rest of my parts in. Replaced all the stock steel stuff w/ Ti and TRX red Rods. Lots of good weight savings, I'll post some #'s later. Got the Futaba 3PM-Fasst radio and really like it. Was able to hook up the BEC glitch-free, so nice to dump the RX pack. Here's a shot:
Bec mount:
http://i7.photobucket.com/albums/y25...4/0e652cf6.jpg

Rx mounted on Top of BEC:

http://i7.photobucket.com/albums/y25...4/ba14f172.jpg

Cleaned up wiring a bit more, but still need to trim batt and ESC wires. The stock roll bar has very convenient clips to hold the deans connectors. :028:
Chassis Final layout:

http://i7.photobucket.com/albums/y25...4/519df288.jpg

Mounted the MM properly. Made a 2nd little mount for this, then bolted to batt tray. Secure but easy removal, and double sided tape sticks well to the mount plastic. The UHMWPE is slippery like teflon, so things need to be bolted down to it.

http://i7.photobucket.com/albums/y25...4/b4b7638e.jpg

Got the CD in. Filled with 500K fluid. I really like driving w/ the CD. Truck turns on a dime, and feels really stable and firmly planted. I do not think my front is unloading too much, but I have a really long chassis and I have a lot of weight moved up front, so this prob helps vs some others who have not had so good of experience w/ the CD. I do not notice a big diff from the solid center in terms of unloading, but I will have to play with it more to be sure. I don't think it would have worked on a 2.5 chassis tho. Too much weight transfer. This one just squats, plants and goes. No wheelies as hard as I try. :027:

The turning radius, diff tuning and brake bias seems well worth it tho if it works. Currently running 50-500-30 in the diffs. I have some tuning to do now, but very pleased with it so far as is.

Lastly, I was able to fit my old shell from my Emaxx. It just fits. :) I'm glad bc the stocker is wasted, and it will be a while before I can paint a new one. Plus I really liked that shell, glad I didn't sell it w/ the Maxx. I'll have to get some better outdoor pics when the weather improves.

http://i7.photobucket.com/albums/y25...4/876b0966.jpg
http://i7.photobucket.com/albums/y25...4/fd236913.jpg

I'll update again w/ some tech notes and some weight info.

Since you are running a center diff, the servo is for the front brakes obviously, but is the motor used for braking the rear??

- bspate -

he has the rear brake kit for the 3.3 tranny he's using.

Ah dang.........I didn't even look close enough at the last pics he posted. I was looking at the pics he had above without the rear brake.......my bad.

Thanks for setting me straight.

- bspate -

Np, there is several evolutions/ stages and it gets is little muddy. I ahve two trannies, one w/ cd, one w/ solid axel. I had the solid axel 1st awaiting the 500K fluid, but now I am just using the CD. Must say I like it alot, despite some front unloading I'm seeing the more I drive it. Really needs 800K lol.

Some action shots of today's run at a local construction site. Its huge, ~200 acres, so lots of different stuff to do.

Did some high speed dirt driving still testing/learning the setup, donuts, mild crawling, huge hill climbing, powerslides, small jumps and even some loop-d-loops. :)

Waiting for the Youtube vid to finish processing, but here are the pics:


http://i7.photobucket.com/albums/y25...4/0faf3e84.jpg
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Video is ready Enjoy!

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Pancake madness..

balooning anyone?

Great vid Finnster!

Great video. It really shows off the power there. When you checked the temp under the body, was the motor 118*F or the esc?

That was the caps on the ESC actually, they tend to run a bit hotter than the actual heatsink.

First to bump my Revo build up thread! Thank god the forum is back as I didn't want to re-write all this!

Updates are that the std center is back in (CD sidelined for now) but I looking to go to a Hi-voltage setup. Namely 10S A123 (33V) and a 1515/2Y Neu (1100kv). The controller will be an MGM 9032. Sweet.

My vids from the RCM bash. Truck held up very well and lasted for two days on that track. Looking at the # of DNFs, I was happy to last throughout, even tho I had my setup all wrong and a steering problem that was giving me fits, Just couldn't make it around the corners half the time and ended up on the lane bumpers.... On the jumps, even when I landed flat, its was so bouncy is would bounce onto the roof:whip:

Oh well, still took home 3rd in the MT class and 2nd place in the brushless open. I'm happy for my first race and learned alot, so I'll be much more ready next time. Still working on the repairs tho. :) The HV setup is nearly complete, so some other goodies to come.
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you're nose diving every time you jump due to the auto brake or whatever it is from your ESC. the motor is slowing the wheels down, which is the same as putting your breaks on with nitro in the air. nose dive!!

if you stay on the thottle, or manage to cut your drag breaks to zero (aren't you running stock brakes with a oneway in the tranny, though?)... hmmm. just try staying on the throttle when you jump. don't peg it, but keep it steady, and you shouldn't nose dive.

i've also heard good things about wings helping the revos in the air quite a bit. grab one of those tekno wings, and get some air!

Actually I was having to nail it just to keep the nose not all the way down. It really wasn't wanting to correct much in the air. The balance is not that off tho. Part of it as well as the F springs were too soft, and I have no motor drag brake, its all done by the mechanical brake, and I have it set to release w/ any input of throttle. My driving looks pretty bad, but you can't really tell how much I was fighting it. Things would have gone nicer w/ a better setup up veh.

GeeRegs pic fpr example of the susp softness in action:
http://img.photobucket.com/albums/v2...1270PScopy.jpg

The announcer is hilarious! You guys hit each other more than the rails, in the air no less. Nice job!