Which is better? (mega/feigao)

[DrKnow65]

Do you have the ubec yet? if so the MM should take the 4S just fine, lots of guys running that way. You HAVE to have the ubec for 4S or else the internal bec will get to hot.

6cfm is very respectable, again though you'll realy have to have the ubec, the wattage the fan pulls will make it even harder on the bec.

[speed demon]

No I haven't gotten a ubec yet. If I stay with a 3S would there be any difference in run time or performance if I got one? Or is this more a thing for longevity of speed control? Sorry for all the questions but all these electronics just baffles me. TIG welding and muscle cars is about the extent of my knowledge.

[DrKnow65]

Tig welding (soooo jelous, I know how, but have no access to one now that I live in Colorado :(

The ubec will put out more amps without dropping in voltage like the internal bec, so your servo's and fan will perform better even on 3S. Also the internal bec is set to 5v and the ubec is adjustable (via the caslt link-not the usb cable for your mm- castle link) so you can set it to 6v, or I like 6.2v because when you load it down it sets right a 6v...
So when you see the servo spec's at 5 and 6v you get an idea of the difference in performance. The ubec will help some with the ESC temps even on 3S, and alot more on 4S (BrianG has done some tests on the performance/heat of the internal bec, you can find it if you do some searching of his posts/threads).

Glad you found a problem (with the settings). I'd still highly recoment the taller pinion gears though, you'll notice a big difference, that mega is a torque monster.

[BrianG]

Originally Posted by DrKnow65

...BrianG has done some tests on the performance/heat of the internal bec, you can find it if you do some searching of his posts/threads...

I just tried to find it but no luck. To summarize; even on 3s the internal BEC heated up quite a bit with a very small load (less than 0.5A). On 2s it was fine.

ANY linear BEC has two enemies: high load current and high battery voltage (vs the 5/6v output). An increase in either (or both) of these values results in lots of heat. A 4s setup with a 2A load will generate around 17 watts of wasted power. Not good on such a small circuit. For anything over 2s or 7 cells, use a UBEC.

[speed demon]

I finally got another run in and the power was awesome(much better then before). It's harder to control then the vxl and I honestly couldn't even make a full power pass going down the road, it was just floating then a slight wind came and I kept spinning out as I was trying to get full power. The MM shut me down once and the temps were 221, motor was 141 which is higher then before so I might try going back to the 26pin. Over all I'm very pleased and will be even happier when my fan comes in.