i think i really like this setup, especially for a smart guy that can get it basically free! to bad i don't know enuff about the slash to know how to part it out and get my money back. i've got a 3905 maxx i'd like to get brushless, but would rather buy a brushless 3908 than upgrade this one, since its running fine the way it is with the titan 775 i put in it.
i also think your truck looks great very clean inside of course you have more wire with two motors, how could you possibly not.
as for the temps i've found outside temp doesn't have a whole lot to do with it, i burnt up my first 775 in single digit temps cuz of my gearing. i'd like to know how high you can gear this safely.
thanks for your postings very helpful info
I started with 6 cell Nimh and then went up to 8 cell 4500mah. I thought that was fast. Then I started using ternigy lipos. Made it much faster. 2s are plenty but I like to throw in the 3s now and again. Did not notice any higher temps with the lipos but get much longer runtime. I have not had any issues with the motors or Esc's. I do have fans on the Esc's and fins on the motors. I can always touch them after running awhile. I do not remember what gearing I ended up with. I have not taken it apart in awhile. I do not take much care of my RC's. I have been jumping alot with it and that has caused me to break more. Mainly shock towers and bulkheads.Originally Posted by Manne
Everybody just cool it and lets just talk about the "R/C". Just take a time out if you need it or whatever.
Anywhooo. I was running 18/68 then 19/ 69 right. I wanted to try 21/68. 23T is the max size pinion. I could not find anything over 19 locally. SO I realized I should knock the spur down. So I bought a 62T and a 58T. The 58 with the 18T gives me the same numbers as 21/68 and allows me to try the 19T. I also got a 62 just because. What I am worried about now is teh rate of change. When I change a pinion +/- a tooth what is going to be the rate of change between the 62 and teh 58. Remeber I started with a 68 and changed 1 tooth on the pinion and it seemed like nothing. So what Spur should I run? If i go with the 58 is it going to be too much of a change when I go up/down a tooth on the Spur? Is all of a sudden 1 tooth going to be like 3? Here some math . Maybe some of you can figure it out for me.
21/68=3.2380 next ratio I was going to try. jumping 2 teeth.
rate of change .1988
rate of change .1809
rate of change .1694
.1988 -.1809= .0179 .1988-.1694=.0294 62T =.0179 & 58T =.0294 change. So almost double? so running a 58T VS a 68T Spur each pinion step would be like having it doubled if I was still running a 68. Am I right? I think I can live with that.
So the rate of change gets small means its actually getting greater cuase its a ratio of 1/X? So .1988/1 < .1694/1 cause its taking more (higher #) to produce 1 turn. Thoughts Anyone? Recommendations on which Spur? I do know that with the lower spur I can always get pinions locally if its too tall. I tried to find "revo gearing" earlier.
We got time on this. I have to swap Spurs and pinions. Its raining and I don't feel like getting wet. Also I have a radar gun comming so we can get some real #s to add to this mess.
Well outside temps along with the lid being off effect the true ESC temps a bit. You should monitor your ESC and motor at least by touch. I'm taking actual readings of both to monitor change and show real numbers since some people have different ideas of what warm is. If you cant keep your hand on it for a few seconds, its too hot. Also you can tell, If you drop down 2 or 3 teeth on the pinion and it goes faster, you were straining the motor. Gearing depends on what your doing. Terain, tire size, type of driving and now batteries. Rough terain you need to be geared down a bit VS pavement. If you put some monster tires or change them at all you need to change gearing. I'm running 8.4V NiMhs. If I was using 11.1 Lipo the gearing would be different. Actually down. Even though the motor turns more with higher volts, the strain is more to so to combat heat you gear down and relieve some of the strain. I could gear this thing to hit high speeds over 200ft but Its going to suck and over heat when I'm bashing in a small area. You have to find a happy medium.
whats the torque and speed like with one vxl system on the e-revo?
Pretty good actually. Same as stock. Probably more effecient. Never ran it long enough to find out.
I had to trim the stock spur to remove it. It was that or remove tranny.
Well If I run the 58T Spur 17T is the lowest I can go without dremeling the motor plate and thats for the front motor. Did not check rear motor. 21/68 Spur combo may have not even fit with again dremeling the plate. My buddy is saying 65 spur I was saying 58 spur. Looks like 62 may be the winner.
Remember I was going to try the 21/68 combo and that was equal to 18/58 but if that was too high I would be hosed. So looks like 62 is it and that will give room to run 21 to 22 (max) pinions. I thought I saw 23 but I was wrong.
Last edited by it8ezbngrn; 01-13-2010 at 09:59 PM.
How many times does he have to say that he did this for the water proofing only. I know it's a public forum and people want to know but why ask the same question over and over when he clearly stated why. It looks great to me and keep up the good work. This is very creative and anyone can pop in a single motor and go. So again the reason he did this was to WATER PROOF it. Keep up the good work man. Terry
X3-RC8T/X2 ERBE/Losi SCTE/SC10 4x4/Baja 5SC/Rusty
So 19/62 is where its going. That is very close to the 21/68 I was going to try and gives room to move up some more. Also Its not so much of a jump. 58 being the lowest Spur and 68 the highest, 62 is in the middle.
Tested it and I still could probaly go up a tooth. I'm still on the same batts from the other day. So 20s maybe 21. Have to play with fresh batts and the lid on and check temps just to be sure. I'm pretty sure 62 is the smallest spur you would want to go ever. I think mine is a rare case cause of the dual motors and low volatge batts. 8.4 is not that high.
I don't see how Tower even lists the te Spurs lower than 58 as an optional part.
Last edited by it8ezbngrn; 01-13-2010 at 10:46 PM.
Thanks for all the info guys! It was very useful for me. I hope you get the gearing right, 21/62 sounds high to me but with out heat issues it's nicer the higher you can get it. Should be pretty fast now then?
Well its 19/62 now. Soon 20/62 and that will be the end.
OK ran today on 19/62 and I finally got the temps up. Its 48 degress outside. I'm running with the lid on. Front (reverse rot) motor is 117 and teh ESC is 110 . The rear motor is 110 and the ESC 90. Still low but why the difference? Th warmer ESC sits behind the other so maybe thats iots maybe the one that rotates in reverse dosen't like it. Also could be a BIG factor is that the pinion slipped forward andnd may have not been in contact. Seen the heat rise and thinking of what happens in 90 degree weather makes me think 20T pinion is the max with a 62 Spur. It still wheelies but not on demand. Only at take off and will ride it for a long ways still sometimes it will rock back and forth on each tire. I orderd heat sinks and fans. After I'm satisfied with the gearing they will go on last. Just a precaution. Batts are warm but not HOT like they used to be with the brushed setup. So I will wait for the parts. Before I and after install the 20s I will record top speed with a radar gun so I know what I gained and see if it is even worth it. SO far I am totally happy. Good torque good speed maybe I could use more but I also used to run a mini revo vxl on 3s That was a good 40+ carI would guess I am in the mid 30s. Well see soon enoiugh. Once its finished I will post a video Maybe I'll make one this weekend.
If you haven't done it already cut a few holes in the windshield of the body and in the rear window to let cool air pass over the chassis to help with cooling. Round holes stay strong and won't crack. Square holes will crack at the corners and ruin the body.
Xerun 150A 2200kv ERBE
Dewalt 14.4v Summit
Did you notice a really big difference between running 1 VXL system and 2?
I've heard that usually one of the VXL's ends up doing a majority of the work, so I was not sure if you would notice a real big difference when adding the second vxl. I was thinking about getting a single vxl setup just for wintertime....not sure I want to take the plunge into a dual vxl....
Does adding the second vxl actually double the power in your opinion? Or just give a minor boost?
I can't speak from experience, but from what I have read, the single VXL setup is not built to handle the weight of a fullsize Revo. It runs fast and therefor less torque. It needs to be geared way down to keep the temps under control. With his dual setup, it sounds to me like the second one is helping a lot because his temps are great and he's geared pretty high.
Phs 2 S-Maxx build- 24/54 gears. Can U say faster?
Top speed would be roughly the same, maybe slighly faster with the twin setup, but acceleration and torque should improve quite a bit.
I got my radar gun! I ran it on fresh batts with the current gearing of 19/62 using 4600 mah 8.4V 7 cell Intellect batteries. Mind you I have good torque and paln on gearing up a tooth. I ran 30mph. I will try again when I have someone to hold the radar gun for me. I was driving and holding the gun. I made two runs right at me and got a high reading of 30mph consistantly. I will gear up as soon as the 20Ts get here and take readings of temps and speed. Remember this is on NiMhs. Lipo would be better. Soon I will have some 3s Lipos to try just for the heck of it. But now its a solid 30 mph with good torque and low temps and good run times.
Sounds very good! nice work man. Can't wait until you get those 3s Lipos! Have you tried the waterproofnes yet? In some way?
Finally got my pinions. So went 20/62 and hit 34 mph. I'll check it again on some fresher batts. Still have torque but it calmed it down a bit going to the higher pionins. Temps were good. 114 degress was the highest temp on the motors and 110 on the ESC and 95 on the batts I believe.
Yes, it was wet out for most of the testing and I have hit a few puddles even though I don't like too.
Threadloc the pinion set screws. I have been having them come loose. I also have tore the tires off the rim messing around on the pavement. So make sure they're glued.
Well this thread is pretty much done till I get my hands on a set of 2S or 3S. With all the parted out Slash 4x4's on ebay picking up one or two VXls should be easy.
I think this is awesome. If you have a couple VXL systems laying around WHY NOT try it???
This is a simple conversion. Sure like some said it's not going to go 60+mph like the MMM, but if I am at the track messing around I don't want to go on 2 wheels when I punch it after a corner. With 3S Lipos it seems this thing could hit 40-50 mph, which is pretty darn fast if you ask me. With 7-cell NiMhs it hits 30-35 mph, which is plenty fast for some people as well.
Just preference really,
Great job man, put up some speeds with the 2S and 3S lipos.
The EMaxxes on dual 3S were hitting 60 MPH. Nice set up you have there. While not a Traxxas, here is mine.Originally Posted by it8ezbngrn
Originally Posted by triggeraa
WOW!!!! I WANT ONE!!!
I just posted a vid on youtube under the same login name "it8ezbngrn".
I put diodes on the servo Y cable. This allows both BECs to feed the reciever but it won't feed back to the other ESC. Use a 3 amp diode and put the silver band towards the reciever on the red wire. You will need two. One for each ESC. This allows you to get the full power of two BECs. If you don't do this you need to cut one of the red wires on one of the ESCs reciever harness. Cause when you turn one on it turns on the other and won't allow you to change anything. So you have to diode or cut a wire. Other than that I am very happy and will gear up another tooth to 20/62.
Nice Vid. The cat was like WTH man... ha.
Are you using an Unslow Harness?
I had my emaxx v-twin on 22/62. Had a really nice "in the groove" sound to it. Good for bashing and giving moderate high speed blasts on pavement.
Very nice build! I've been considering doing a V-Twin on one of my Emaxxes, for basically the same reasons as you've done here. (I have an 8yr old son and a 5yr old daughter that like to play with my "toys" as much as I do ) I'm not terribly interested in a huge power or speed increase, but an increase in run times coupled with a reduction in temps of the motors and batteries and reducing the amount of maintenance sounds like a win-win to me!
Newbie Helicopter Enthusiast
Thread bumpage but WOOOOOOWWW that is SOO COOL!Originally Posted by triggeraa
PLEASE do not PM me and immediately go offline :p
Its an old school MRC Thunder King. I had a dual VXL E-maxx for a while. Running dual 3s, it was just as fast an MMM setup.
More RC's than most of the people here.
t kind of car is that and nice build by the way.
if you dont want your mamba max combo give it too me, i would take one of those ANY day, all i need is 1 more vxl esc and then i can run twin vxl in my erevo
Nice build, it8. People have always bashed these kinds of builds with 'single brushless is better' or 'it's not worth the money' but they are always the people that never tried it. Looking clean, nice custom ESC mounting plate too.
My guess why the front motor (reverse rotation) is hotter is simply because it doesn't have a good heatsink like the rear motor does, the motor mount. Holes in the body will definitely help, but I doubt it's a problem since the temps are relatively low compared to the maximum allowed.
I've put my own 540 sized brushless motor in my 8.5lb Revo conversion (LRP X-12 4.0). Even though it had a very low gearing (13/54 0.8M) and two gears, there was not enough axle torque. The one thing I did like from the 540 setup was the high RPM scream that you just don't get with larger motors. I imagine the sound is twice as good with two of them on the truck. (: Keep up the good work!
sorry to resurrect such an old thread. I'm trying to do the same thing. I have a twin brushed E Revo with the single EVX-2 ESC and the two Titan 550 motors. I see that you have installed 2 VXL3S ESC's. Presumably I can use any off the shelf brushless ESC ? My questions are how did you manage to get two ESC's off the one receiver ? Did you buy a splitter cable for channel 2 on the receiver? Also, one of my motors says reverse orientation, I presume that means that this motor is running in the opposite direction to the other. If so, how did you get one of your brushless motors to run in reverse?
sorry for the noob questions - I'm a 1/10 touring car driver mainly and the world of Traxxas is totally new to me.
thank you in advance!
1) Y-Adapter to run two esc in parallel
2) To reverse a brushless motor just swap two of the three motor wires
But why do you plan a twin brushless setup? Doesn't make sense to me