more power and speed out of mamba max and 8xl

[nitrorube]

guys i got my feigao 8xl and hooked it up yesterday to my mamba max and emaxx with 2 cheap 6 cell packs and yes it made me happy but i want more power and speed,will 2 2 cell lipos make a difference,and suggestions?ide like to thank all that have helped me with this new project and to mike for the fast shipping

[t-maxxracer32]

of course it would get you more speed and power! lots more!

your using 2 crappy 6 cell packs that are pretty close in voltage but im sure they dont put at near as many amps as 2 nice 2 cell lipos would.

there are some smarter people here who could give you technical answers so ima just leave it at that.

yes. a 4s lipo (2 2s lipos) will give you way more power.

[BrianG]

Yeah, t-maxx is right. Those 6 cell packs have close to the same nominal voltage as a 4s (or dual 2s) pack, but the NiMHs voltage will drop more under load, which reduces the motor speed. Appropriately sized lipos hold their voltage better under load, which translates to faster speeds and better throttle response.

For example, a typical zapped NiMH cell is good for around 30A while maintaining 1.2v per cell. If you draw more than that, the voltage starts to fall because of internal resistance. So, instead of 14.4v, you might be getting only 12v (1v per cell) or less under load. A good lipo can maintain 3.5-3.6v per cell with much higher currents so it feels much stronger and can go faster. After all, motor speed is voltage X motor KV...

[nitrorube]

thanks guys , brian you have helped me a few times now,you know your sh**,thanks but besides the batteries is there anything else i can do,even with the cheap nimh there is a great difference over stock,where is the best place to order lipos?

[t-maxxracer32]

im going to say to just email mike.

im sure he has something for you

evo 25s, 30s, neu batteries.

hes got most of the quality packs

[jhautz]

The Neu Energy Lipos are a good deal. Good quality and the price is very reasonable compared to Enerland based packs. Check the RCM store he has a few different ones.

ANother good pack its the Trackpower gold ones. They are reasonable and very good quality also. and for an emax would be a perfect drop in fit.

[Patrick]

Is it a new e-maxx or the older one? What's your gearing?

[nitrorube]

its a new emaxx and im running a 18 tooth and stock everything else

[Patrick]

18/68 on the new maxx is geared at about 19.6:1 final drive ratio. With a 8xl on that voltage your only geared for somewhere in the mid 20's even if the batteries hold decent voltage. I'd try to gear it somewhere around maybe 14:1 to 16:1 depending on what sort of driving you do and how temps go.
Good batteries will also help a lot, especially if you change the gearing and start drawing more amps.

[nitrorube]

so do you suggest a different pinion or spur

[Patrick]

Bigger pinion and/or smaller spur.
Use BrianG's calculator to find a spur and pinion combo that puts the final drive ratio somewhere between 14:1 and 16:1. Bigger pinions make the fdr go down. Bigger spurs make the fdr go up. I'm not really sure what different size spurs fit on the new e-maxx.
The lower the fdr the more load you'll be putting on things, so you may need to watch temps a bit more. Good batteries will also become more important when geared for higher speeds.
The type of driving you do will affect what gearing is best for you.

[nitrorube]

thanks for the help,ill play around with that,i dont know either if traxxas makes any other spur gears for the new emaxx,anybody know?

[suicideneil]

I believe they sell 62, 65 & 68 tooth spurs for the 3905, and 12-22 tooth pinions. Changing one tooth on the pinion is roughly the same as changing 3-4 teeth on the spur, so it pays to have a selection of both really. 62/22 should give you about 35mph-ish, but I dunno if the spur and pinion will mesh- apparently the motor mount that is to the side of the tranny (rather than above it) offers you more adjustment space before the motor hits the tranny....

[nitrorube]

thanks alot

[JerryF504]

Jato spur gears will fit the 3905 also. They are available with 54, 56, and 58 teeth.