I know there are several threads on the E-Maxx but I wanted to make a thread that just concentrates on single motor variants so its easier for people to find in a search. This seems to be a controversial topic on the Traxxas boards especially when it comes to running a single VXL system. So lets keep it civil and try to put out as much good info for people.

Getting it started, I will talk about my experiences with a single VXL system that I have in my E-Maxx. I was a schmuck and forgot about my exposed battery bars when I first took it in the water. The net result was a bad battery that I should have never hooked back up to my EVX-2. The net result upon hook up was a fried ESC. I needed a replacement because my little nephew was really excited to see the truck go. My LHS owner, suggested a VXL system. So I took the plunge. I figured if it didn't work out I would have a quality system to use with another project of mine. Here are my findings for the setup:

I. Batteries and Pinions

I used 2 different batteries. One was a Venom NiMH 7 cell 5000mah Hump pack and the other was a TC 2s 5400mah LiPo. I have a 3s Flightpower 25C 5000mah on order so those results will come later. On pinions I started very light with a 9 pinion to be safe and them moved over to a 15 tooth and soon to a 16 and possibly a 17 depending on heat. I used the stock 68 tooth spur.

II. Initial run on 9 pinion with Venom pack

No problems with heat. Ran slow but even with a small pinion the wheels still popped up a bit from a standing start. Not much top end but that was expected with such a small pinion. However the low-end torque was awesome I powered up steep inclines with no sign of losing momentum. This was more of a test-the-water run.

III. Second run on 15 tooth pinion with Venom pack and installed cooling fan on the ESC

Very different handling. Popped wheelies from a standing start. My radio is the stock TQ so I had deadband issues. When I move it to my Spektrum DX3 .0 system that will be a non-issue. It was as fast or slightly faster than stock. I have a very unscientific method for measuring speed - jump distance. I have a small BMX trail in the woods near my house with a small double. The stock config easily cleared the second hump as did the new config and even gained a little more distance on a couple of runs.

Runtime was about 18 minutes of solid power before it started to show signs of slowing down.

Heatwise the ESC was a non-factor the fan works very well wasn't even hot to the touch so I didn't even measure it. The motor peaked at about 155-160 so thats a little hot but nothing a heatsink can't remedy (I believe the Velineon motor can handle up to 200 anyway). The battery, however, hit 145. I am not sure if that is too hot or if that is normal for NiMH batteries.

IV. 15 tooth Pinion with 2s 5400Mah LiPo

Interesting find here. Seemed to have more power. Stronger off-the line. Wheelied easy (when deadband issues didn't arise). Seemed a tad faster that the Venom run. Jump test was comparable to venom run too close to call in terms of whether or not it was jumping further. Definitely faster than stock.

Heatwise. Motor was the same as the venom/15 tooth run. ESC was again a non-issue and the battery.....luke warm at hottest.

Runtime was approximately 28 mins before the LiPo cutoff kicked in. (the one downside is that it seems to cut it off a little early but early is better than late with a LiPo.

V Conclusion thus far

LiPo is the way to go for this setup for sure. With proper ventialltion and a heat sink on the motor the 3s should pack a nice punch and be much faster than stock with no thermal issues. I am going to up the pinion to a 16 tooth when my 3s comes in. It is a $184 pack normally used in electric helis rated at 25C with 50C burst.

VI. Other notes

Weight is a factor here. The stock wheels and tires are pretty heavy; I used a Proline set that was noticably lighter. I am also going to switch to a single steering servo (futaba S9452 digital high torque servo) which will further reduce weight and increase run time. The 2 7-cell pack that I used with the stock motors weighed about 1.5lbs (they had super duty battery bars that were very thick) a 3s LiPo weighs far less than that and add in the weight of the heavy stock motors being subbed for a a single lighter brushless (the Velineon is lighter than a single Titan by a good amount I will get hard numbers when I get a scale [I need one for ebay anyway]). All in all I think I shed close to 1.75 pounds or more of weight.

Battery mounting. I used the stock foam spacers to create a bridge across each of the battery trays and used a piece of cardboard with thick double-sided tape mounted on the spine to mount the batteries transversely across the chassis bewtween the motor and ESC. To lock it down, I notched a couple of slits on both sides in the batter trays and used velcro straps to keep it secure. The battery doesn't budge and the weight is better distributed.

I am sorry that my results could not be more accurate but I lack a radar device and scales. So any hard numbers would be appreciated.

Remember to keep it civil and post your single motor variants of the E-Maxx and let us know how it goes for you.

My friend's E-Maxx's (3905) setup:

-Mamba Max ESC with Novak fan
-Align 600XL 1700kV brushless motor w/ 40mm fan mounted to the second motor mount spot blowing on it
-2x Orion 2S 4800MaH LiPo
-24/68 gearing

Observation: Insane low-end power. We're having problems with the truck exhibiting excessive torque steer, so he has to ease into the throttle slowly from a dead stop, otherwise it's torque steer or it's on the lid. Top-end with this configuration is pretty stout, and the highest speed we got with the radar gun so far is 42 MPH. Temperature on the motor never exceeds 98F, ESC is running at 105F right off the track after 5-7 minute of running. He is in the process of looking for center/drive CVDs, the stock ones are twisting and snapping.

I have a Trakpower 3s LiPo on order and it should be here by this saturday. I will hopefully have access to a radar gun so I can be a little more scientific.