Brushless E-Revo Help?
 

Hi guys.

I am making a Brushless E-Revo with Feigao 7XL and MMM ESC and 14 Cells altogether.

1. What gearing is the BEST for this ESC/Motor/Battery Combo?

2. Are these batteries any good?

http://www.promatchracing.com/proddetail.php?prod=7470S

3. Should I use a BEC for this set-up?

Thanks, Austin.

What speed are you wanting? 40-45 mph is usually in the ballpark of what most people shoot for. You can use this to get the gearing for the speed you want. Then, I'd get a couple spur options (spurs are cheaper than pinions) in case things heat up more than you like.

And personally, I'd go with an 8XL for 14 cells. 40krpm on the 7XL is a bit on the high side IMO.

How fast will I be going with 14 cells on the 8XL and on the 7XL?

Technically, the 7XL will go faster with the same gearing, but the motor will probably heat up more/faster since Feigaos don't like rpms much over 30-35k. You can recover any speed loss with gearing (within reasonable limits of course).

Ok, I'll get a 8XL. I calculated my speed and it said 45MPH. Nice speed.

I am buying 16-20T Pinions for $4.29 a piece at Amain. I can go 50MPH with 19T one but does that mean it could over heat? (Meaning the Motor,ESC, or Batts?)

At high speeds/gearing, you're gonna start overheating the ESC and batteries. If you're planning on getting a few pinions, start low and get a couple options. Not sure where you are geographically, but with summer around the corner, the ESC and batteries won't like too much added heat...

Low meaning like 16T Pinion or lower? I am getting an ESC Fan also.

Without calculating the speed with the various pinions, I'd shoot for whatever pinion gets you ~40mph first. Then go from there.

Ok, Thats a 15T Pinion. What if the ESC/Motor still heats up then? And I can't gear it down to cool it down. Then what happens?

Well, gearing down will help. Just be aware that no matter what, the Feigao will get hot after a 1/2 hour or so. Just keep motor temps at around 40*F above ambient, or ~150*F max. Figure around 10*F less for the ESC.

I use a 40tooth spur and 16 tooth pinion in my Revo and a Feigao 8XL on 4s lipo's and after about 20-25 minutes my motor is about 170 degrees. It's a little on the hot side but seems to be holding up so far.

Ok. I'll try that. What is the temp outside?

Here's the list:

1. Feigao 8XL
2. Mamba Monster Max ESC
3. 2 4600mAh 7 Cell Batts (SPC)
4. 14T-18T Pinions
5. 40T Spur
6. Traxxas Male Connectors (2)
7. Traxxas Siries Connector

Is there such thing as a motor fan?

I think the 14T pinion will be the best option for temps IMO. Also, are you gonna go single speed tranny (using the mod) or keep it two speed? That can make a BIG difference in your gear choices.

If you haven't done so, you should read the sticky about using the nitro tranny. It lists the options and the advantages/disadvantages.

It's about 65-70 degrees when i get those motor temps.

I'm keeping the 2 Speed. Mike, are you running the Single or Two speed?

OK then, the two speed will allow you to choose more aggressive spur/pinion combos because first gear will get you going and second will get you the top-end. You could easily go with 40/16 or maybe even 40/18.

But, just remember that you will have to keep mechanical brakes, and unless you retain the stock (weak) reversing mechanism, you won't have reverse.

SWEET!!!!!!!!!!

Ok, I have FOC though.

I am locked in second gear.

Oh. Wouldn't it be faster on 2 speed? Also, What conversion are you using? I am going to use the Tekno one but I don't like the Elctri-Clutch at all so I am just buying Pinions instead.

I am using the Tekno battery tray and reciever box, and for the motor i'm using the RCM motor mount. I don't really like the idea of the Tekno clutch.

Oh, I don't like that Clutch either. Pretty stupid idea. Can I just throw a pinion on there instead of that clutch? Also, Do you have any pics of yours? It sounds pretty sweet.

I am going to get the RC-Monster Mount, Tekno Battery Mount and Battery Straps. That WAY less $$$ then the whole kit.

be careful of that teckno battery mount. If you put 14 cells on it, that's quite a bit of weight. Mine broke while landing using the trueRC 8000mAh 4s2p. The weight of the pack bend the center support and broke the tray where it mounts at the rear. The center support piece on the chassis is snapped off now, and I have to come up with some sort of rig job to hold my batteries in.

J.

Here is my E-Revo.
http://www.rc-monster.com/forum/showthread.php?t=12050

Ok, I'll see how it stands up.

Nice Revo Mike!

Ok, Here's the final list:

Feigao 8XL
MMM ESC
SPC 7-Cell 4600mAh
15-19 Pinions
40t Spur
RC-Monster Mount
Tekno Battery Tray w/ Straps
Tekno ESC Mount
Novak Fan
Tekno Throttle Mount
Traxxas Series Adapter

CAN'T WAIT!

What is your guys opinion on going 16 Cells instead of 14 Cells. Do you think I should? Because I want the most power and speed I can get with Nimh's for now until I can go Lipo. Is going 16 Cells worth it?

I saw the Novak H-V 6.5. Is that any good? It looks good. Is it worth buying over the Feigao?

The Novak HV 6.5 is totally not worth the $280. You can get an monster max esc + feigao XL motor for about $250 and the Novak will not even be able to handle as much load or go as fast. Also 16 cells is probably too heavy to keep the part breakage low and the revo would handle like a brick. Plus the 8XL would have plenty over-the-top power on 14 cells.

Oh, Ok. How about the 4.5? Same as 6.5?

Any other better Motor than the Feigao that is the same price or a LITTLE higher?

Also, How about the Feigao 9L?

The 4.5 is also not worth getting. The 9L is much too small for an E-Revo. The 9xl on the other hand would do great in one. Maybe take a look at a used Hacker motor, or Mega motor...?

I just did some research on the 6.5 about 45 mph with 14 cells. And it's great. Watched vids, and talked to a person. What's soo bad about it?

Like I said, it costs more money than the 8XL + MMM. On 14 cells (16.8v) the 8XL will turn 34k rpm, which is good for 42-47 mph depending on the gearing. Just because the Feigao XL motors only cost $80 that doesn't mean they won't perform as well or better than the HV 6.5 or 4.5. They are at least as good quality, and the performance of these are very well documented here on RC-Monster. I personally am going for 9XL on 4s lipo (27k motor rpm). If you must have a higher quality motor, the MMM with motor combo is probably coming out in a few months for around the price of the Novak HV.