noob e-revo?
 

I am planning on making an e-revo with the e-maxx trans and motors with the exv esc but I see alot of people are using a bec or is this used if only using the revo trans with a brushless motor? please help...
Thanks

A BEC or UBEC is used depending on the set up of your RC. I take it your using all the stock Emaxx stuff correct? What batteries and how many cells? Most or all ESC's have an internal BEC. They can only handle so much from the batteries you plan to use. I have an Emaxx tranny with a MM ESC. I plan to use 2s2p Lipo's ran in serious. I have to wire in a UBEC to handle the Lipo's. The internal BEC of the MM can't handle 4s. I hope this helps.

well for now I am going to use everything stock until I see how it handles so stock exv esc and 12 cells so I don't think I would need the ubec unless I went to lipos correct? Also if I use the e-maxx trans can I still use the 2 speed or do i have to lock it in 1st or 2nd gear? I appreciate any and all the help I can get pics of where to dremmel out on the revo chassis would help if possible...
Thanks

I can't say yes or no to that. I don't have hands on experiance with the EVX. Like I said before your ESC is rated for so many volts or cells that it can handle. You need to see how many volts or cells the EVX can handle. If it can handle 12 cells then you should be fine. If not then you need a UBEC. You don't need a UBEC just because you are using Lipo's. Here's and old thread but it may help you:

http://www.rc-monster.com/forum/showthread.php?t=576


As for the tranny being locked into 2nd its up to you. You "could" leave it so you could shift it. But think about the mods you would have to do on the chassis. The Emaxx and Revo shifting servo are not in the same place. You would have to modify things for that. Plus more wires to run. More work then needed IMO. 2nd gear locked in is easier on the motors, ESC, and batteries. Think of it like this. Have you ever tried pushing a manual shifting truck? Which gear is easier to push it in 1st or 5th? You motors are pushing your RC truck. Which gear is going to be easier? Just my opinion. Its easy to modify the tranny. Brian has some pics if you need help. I used everthing in that was in the tranny already. 3 holes and 3 bolts later mine was locked. That easy.

here's another link to Brians pics:

http://scriptasylum.com/bl_conversions/

Just to be clear: The Revo doesn't need a servo to shift, but if the 2 speed is left intact, you can't have motor brake/reverse. The emaxx tranny is totally different and does need a shifting servo for two speed, but you have motor brake/reverse in both speeds.

well the exv esc can only handle 12 cells but that is fine for me for now and I will be using the e-maxx tranny is it possible to lock it into 2nd gear? or should I keep the 1st and 2nd gear with the shift servo?

You can lock into 2nd with a spring or such and then add a servo later to go two speed.

An UBEC is only about $15 and will take some load off the ESC. Castle have a new onle out for low $20's which is very configuable to.

I thought EVX took 14 ok...

is there a photo gallery on this forum? I tried the one that I saw but it did not work I would like to see some peoples pics on how and what they did for the build using the e-maxx tranny and revo chassis...thanks

Look for Dafni's thread on the Maxx tranny in Revo. It has 16K reads. :) I have one buried somewhere, but I didn't use a 2spd.

I would prolly try to keep the 2spd if you are using titans. It will run cooler, longer and be more fun w/ 1st IMO. Only w/BL is it useless.

I would go with a single st servo and then mount a shifting servo where the other st servo goes. This is what Dafni did IIRC. Making a servo mount should be the trickiest part of this, but not too bad.

A Ubec is to take pressure of the ESCs BEC. The way it steps down voltage creates heat. More step down, more heat. Above ~10V or so I would use a UBEC. The EVX is wierd that it runs two channels (one for ea batt) and BEC draws from just one channel so the step down from 7.2V is not severe.

This is my build - I used the old motor mount for a micro servo. Servo mount was easy for a micro servo using a couple of standoffs.

http://www.rc-monster.com/forum/showthread.php?t=7530

ok I am not sure but I seen some e-revos with the e-maxx trans in backwards? :neutral:and some with it installed like it is in the e-maxx what would be a good way and easier to do but remember I am going to use the stock setup from the e-maxx first then hopefully going brushless if my wallet allows me :lol:

ok so I can mount it either way then right?

yes, as long as you are planning on using a sensorless motor, if it runs backwards , just swap two of the motor wires, otherwise flip the diffs

Arct1k how much did you have to dremmel off of the revo chassis to fit the e-maxx trans also did you have to drill new holes to mount it? and any close up pics of how much you had to dremmel out?

I'll try to get some pics but I dremmelled more than most in order to get the trans as straight as possible.

Just lined it up and started cutting. The existing trans mounting holes don't exactly line up so need a little modding there - I ended up almost cutting "channels" for the other 4 mount points.

I also run the titanium skid too - At some point I have a whole new chassis (all of $10 for a 2.5) that I was going to have another go with - But at the moment its is a case if it isn't broke leave it alone (i.e. just wait a week or two until you break it!)

hey
 

the evx is good for 14 cells, one of the first threads you stated it's only good to twelve, it handles 14 all day, and you DO NOT need a bec with an evx, especially with titan motors, makes your install alot easier, also, i run a lever on my e-maxx tranny for shifting, it requires me to bring the truck to me when I need to shift, but it eliminated the servo, and i'm either bashing or hill climbing, so I know what gear I need. get yourself some 7 cell packs and wake up those titans a little!

well I just started dremeling the chassis last night and so far so good I just need to cut the holes for the mounting points for the trans...:yipi:

here is what I got so far...

"Can ya tell what it is yet?"

Try test fitting the centre shafts, and you will see if you need to remove any material on the chassis around the rear output shaft of the tranny (thats the main area of concern usually).

yupp you are right suicideneil right at the rear :yes: the pins on the shaft hit the chassis preventing it to turn... Thanks

well I did dremel off more of the chassis like suicideneil had mentioned here is the new pic with one battery holder mounted

So far so good. Clever use of an old Emaxx chassis there, will look semi-factory with both battery holders mounted (if thats the intention). Just make sure they're bolted to the existing chassis really well, wouldnt want them to separate at speed....

Wow! You didn't need to cut anything off the rear - where it was rubbing you just needed to use the grinding wheel to shave off a 1mm or 2. That's quite agressive - hopefully won't hurt the chassis too much.

I'd round off your cuts to stop stress risers.

Cheers

well here are more pics of my project build

Have you had a chance to test this with the Titans? You might want to consider BL motor if you can't get the speed you want.

I have a funny feeling this is how the E-revo will look , more or less, when/if Traxxas ever get their finger out and build it. You may want to add a guard to that steering servo- looks a little exposed sticking out the bottom like that (just as it does on a stock revo/maxx). This is another one for the books I reckon, another unique creation.

thanks suicideneil I was planning on doing that and a guard for the tranny as well

Here is my finished E-Revo minus the guards I would love to get a video of this monster in action but I have no way of getting it to the computer:grrrrrr:but oh well it is mostly finished and I can run it:yipi:
Thanks for all of the help....

Wow, you finished that amazingly quickly, I think its a testament to how simple the chassis is to work on and how interchangeable parts are between vehicles (with a little filing here and there). Nice work & go enjoy the fruits of your labour!

Here is my contribution;

Brings a whole new meaning to "E-Revo." Nice truck!!! Congrats.

Thanks I am going to be testing it out this weekend when I have some free time...lol

Great job! Out of all the conversions that have been done on here, I believe yours is actually the first to utilize EMaxx battery trays - suprising, huh!?!?!

When you do end up going brushless, just remember that your tranny is backwards. I forgot all about that, and when I put a sensored system in it (HV-Maxx), I ended up having to flip the diffs to get it to run in the right direction.

I just got done testing my e-revo and it gets about the same speed as the e-maxx which makes me happy for now...

Yeah, I wouldnt expect it to run much faster than an E-maxx since it uses the same motors & tranny. You might be able to gear up a tooth or two since it is lighter than the Emaxx, but until you step-up to BL power then the speed difference wont be huge. Handling and general coolness though will increase hugely...

I am planning on going lipo soon but I need to know what size or type the exv will handle?

A maxiumum of 4s. In the case of the evx you will need 2x 2s lipo batteries since it has two sets of input leads- a 2s battery plugs into each one.

I am going to go brushless soon I was told to flip the diffs so just so i get this right take the top of the diff and put it on the bottom for both diffs correct...

Thats correct