Originally Posted by Pulse_

I wonder how it would hold up without a slipper, it would be interesting to see

Originally Posted by Davidka

That's the tough thing about typical 1/8th cars, the diff takes a fairly large chunk of space. I chose the Tekno because I liked that the diff was moved out of the pack's "way" allowing the whole thing to be narrower, as well as having a more forward weight bias.

Part of the difference with the saddle layout is that it inherently has more weight to the rear (though the motor is a pretty heavy part). If someone figures out how to shoehorn 5000mah+ into a "shorty" pack then that would present a really cool tuning option for the saddle cars.

Originally Posted by hakmazter

How about something like this prototype?



Narrow enough?

Originally Posted by teknorc

Great question. I was discussing this exact topic last night at our club race. Here's my opinion. With all of the dual pack layouts coming out, it's going to be hard to get the real facts out there. But here's a start...

Putting aside the practicality of a 1 pack vs. 2 pack discussion, it comes down to balance. At first glance the 2 pack setup looks more balanced, but it's actually way off balance to the motor side. The other issue is that there is a lot more weight towards the rear.

First, let's look at the side-to-side balance. Yes the packs cancel each other out and are balanced. But the imbalance is when you get to the front. On one side you have an ESC @ ~85-120g and a servo @ ~65-70g. Pretty much, the maximum weight you have on the right front is ~190g. If you are running a Tekin or MMP, it's more like 150g. Sometimes the RX is on the right side, but usually it's on top somewhere. On the left side you have the motor at ~340-420g. In a best case, there is a 150g discrepancy. That's over 5oz out of balance. At a worst case, you have roughly a 270g difference - almost 10oz!!!

The Durango is even worse because the RX AND ESC are centered and very high, negating the lower cg of a dual pack setup. This puts only the servo and PT on the other side. The ESC is also moved farther back. Doing the same math above, the Durango is out of balance by at least 10oz.

Second issue with dual pack layouts, the weight is too far back to carry maximum corner speed. Granted the car will feel more planted on-power due to more weight on the rear, but overall industry trends are moving everything as far forward as possible, because this yields a faster, more predictable, race car .

So, not only are those layouts out of balance (we weighed a Serpent last night and verified this), but the one advantage they do have (cg) is somewhat mitigated by moving other components higher. You are also limited to 'buggy' motors. Some people won't care, but having the motor and sensor wire so close to the steering posts may cause issues under hard impacts. The option to run longer motors doesn't hurt anything.

Overall, we feel the V4 layout is the optimal combination of side-to-side, forward weight, and CG.

A single 4s pack is roughly 580-600g. Using the same figures from above, the motor/esc/servo combo is ~490g. So at the worst, you are off by 110g. Add in the receiver and transponder ~20g, wire, and you are off by less than 90g at a worst case. Find a battery that is 500g or run a slightly larger motor and you are dead even. I run a 4s/4200 in my buggy and it is with ~10g left-to-right.

The weight is also just slightly more centered with a V4 single pack setup since the batteries don't have to clear the center diff.

Now consider the battery charging and changing with 2 packs as opposed to 1. Extra wire for the series connection, extra hard case, extra terminals, slightly different discharge rates between packs, etc. and you can see why we think the single pack forward with the opposed motor/esc/servo/rx is the best option.

We are going to be posting this info on our website soon so people can decide for themselves. We're just puzzled why some manufacturers would tout a balanced setup when they know perfectly well that it's not .

edit: With the Tekno conversions you can run the Traktion Drive slipper setup as well.

Originally Posted by Davidka

Of course there can. Right now the volumes are such that companies aren't developing electric buggies from the ground up, they're just converting nitro cars.

I would love to see a pair of small outrunner motors driving front and rear, eliminating the center diff and "diffing" with the electronics, batteries in the center. That would take a big commitment from a chassis maker and possibly a bigger one from a speed control maker.