E-Maxx Dual Titan 775 Torque

When Traxxas released the Summit, it came standard with a new brushed motor designed for torque, the Titan 775.  It uses both sets of output wires that stock EVX-2 would normally use to power a pair of Titan 550 motors as it draws more power than a traditional Titan 550.  Many people started replacing their Titan 550 pairs in their E-Maxxes and E-Revos with a single Titan 775 for the increased torque albeit at the cost of a bit of speed.

We decided to take it one step further.

The Build

I’ve had the Traxxas E-Maxx for a long time getting it the same month the 3905 model was released.  This was a major improvement over the old E-Maxx in nearly every way.  But I’m rarely satisfied to let things alone.  I started by beefing up the A-Arms with a set of RPM A-Arms all the way around.  I then upgraded the bulkheads to a set of Integy bulkheads intended for the nitro T-Maxx.  I had to slightly modify the chassis to make them fit but it was definitely worth it after snapping two sets of bulkheads and ripping the RC apart several times to fix it.  I also upgraded the receiver to a Spektrum DSM.

Not satisfied with the speed and torque that the dual Titan 550s were putting out compared to my E-Revo with a Castle Creations Mamba Monster in it, I decided to see what I could do differently.  I wanted to achieve brushless (or at least near-brushless) levels of power without sacrificing the waterproof nature of this truck.  Afterall the E-Maxx 3905 was the very first Traxxas vehicle to have the now signature Traxxas waterproofing.  I looked for waterproof brushless systems and found that none existed for this size of RC.  Even though a single Titan 775 is  just barely slower than the dual 550s in it, I didn’t want to take a step down in speed.  That’s when I got the idea to double it up.

I started by installed a larger motor mount built by Kershaw Designs designed for a similar system that they make that uses modified drill motors.  I had to forgo the stock spur guard as it not longer fit with the new motor mount.  I had a spare Traxxas EVX-2 ESC that came stock on my E-Revo but wasn’t using anymore since I’d upgraded it to brushless.  I wired up both ESCs to the same power connectors, and used a servo Y-Adapter to connect them both to the receiver.  Finally I connected all four sets of power wires to the two motors being careful that each ESC was only connected to one motor.  I topped it all off with a pair of 25T pinion gears.  I was going for speed with this configuration so the stock 17T Pinion Gear wasn’t going to cut it.

First Run

Once everything was wired up, I turned on both ESCs and re-calibrated both ESCs simultaneously to the remote. I checked to make sure the motors were spinning the right way and let it go.  Immediately there was a  very noticeable increase in torque over the stock motors.  Pulling the throttle to max resulted in at least a 30% increase over the stock speed.  The extra torque made the E-Maxx easily power over boulevards, rocks, and anything that got in it’s way.  Reversing then immediately pulling full throttle causes the RC to flip right over.

Lining up the E-Maxx next to my brushless E-Revo, It held it’s own, at least until the Revo got to full speed.  Even with the dual Titan 775s, it was no match for the top speed of a good brushless system.  It does easily keep up in torque though, possibly even exceeding the brushless E-Revo. Not much can stand in this truck’s way.  (Speed rock crawling, anyone?)

Conclusion & Final Thoughts

I set out to make a powerful basher that could work in any conditions, dirt, rain, snow, tarmac, or anything else nature could throw at it.  I succeeded.  I don’t have to worry about frying an expensive brushless system by running through a puddle or running in snow. (Which in Alberta allows me to run this truck year round.)  If I hit a pole, it bounces off and keeps going.  Curbs it drives right up.  This RC is now an unstoppable beast.

It does suck down batteries faster than it did stock, but less quickly than I had expected.  I’m still able to get a good 20 minutes runtime on a pair of MaxAmps 4700mAh 7-Cell NiMHs.  I don’t believe this RC would have any problem keeping up with a Nitro T-Maxx, especially on a track where the extra torque would allow it to accelerate more quickly that most Nitro RCs.  It wasn’t built for the track though, this is a basher to the core.  With the upgraded parts and overkill powertrain, this thing keeps going where few other RCs can.

Hop-Ups:

  • Dual Traxxas EVX-2 ESCs
  • Dual Traxxas Titan 775 Motors
  • RPM Racing A-Arms (Standard front, True-Track Rear)
  • RPM Racing Shock Towers
  • Integy Aluminum Bulkheads
  • Integy Shock Springs (Purple)
  • Spektrum SR3000 Receiver
  • Maxamps 4700mAH Batteries