MGM compro + feigao 6s + TC4 - RC-Monster Forums

MikeyLikesItSI · 06:48 PM

Hey guys, even though this is my first post, i've been lurking around for some time now.

I purchased an MGM Compro 8012 and feigao 6s from mike a month or so ago. I put this setup in a 1/12th scale pan car The thing was definitly a freakin rocket. 65+ MPH on 6 cells. i used a 20 tooth 48p pinion and a 75 tooth spur. Overall final ratio was 3.75:1.

I reprogramed the ESC so it would accelerate over 1 second, otherwise it would just spin out under hard acceleration. Well, after going through 2 sets of tires in only 4 or 5 battery packs, i decided the car isn't for me. Moving on......

I purchased and just assembled a brand new RC10TC4. Using the same 20 tooth pinion, and the stock 72 tooth spur gives a 3.6:1 ratio. The differentials, front and rear, are 2.5:1, for an over all ratio of 9:1. Now, given the much higher ratio, i figured it would obviously not reach the same speeds as the 1/12th car, but should rev fast with lots of torque. I reprogrammed it to accelerate quicker (now having the advantage of four wheel drive as well). Still using 6 cells. Well, it takes 100 feet or more for the car to reach top speed. the thing is an absolute dog out of the hole. It takes forever to come up to speed. I tried several different programming settings. After about 5 minutes, the motor was only luke warm, the controller wasn't much warmer then that, and the battery pack was quite cool. Shouldn't this thing be ripping up some asphualt? any idea's?

My rc10t with the novak 4300 brushless system has close to the same ratio, and wheelies off the line and ROOSTS like mad in dirt!

Sorry for the long post :o

Thanks guys!
Mikey

lipomax · 05.20.2005, 07:04 PM

The 6s is not really a good motor. I really don't recommend that motor for anything but say drag racing. That motor works well if it's got a pretty big pinion, batteries that LIKE to give over 100 amps etc.

The TC4 is much better off with a "380" size rotor. So, motors such as the Lehner 1520, 1525, Hacker C40 S, Kontronik Twist are probably the ultimate motors for a 1/10 TC. The Basic series and Plettenberg are a bit larger and need more power to get them going and so I don't think those are the ideal motors either.

That motor has a really heavy rotor too. BTW, are you sure you got the MGM programmed right?

MikeyLikesItSI · 07:18 PM

by why did it propel the 12l3 so well, and why does the novak push (still 540 motor) the rc10 so freakin hard? the 4300kv novak should be about the equivalant of the 7s feigao, no?

You say the 6s is a drag motor, well, drag racing calls for SERIOUS acceleration..... this thing just takes its sweet time spooling up.

lipomax · 05.20.2005, 08:55 PM

Yeah, drag racing with like 12 cells and TALL gearing and with batteries that can deliver 200 amp spikes and a controller that won't smoke with 200 amp peaks.

Anything propels the 12L3 well. That thing is so freaking light.

I didn't have the Feigao 6s, but the Hacker B50 6s. I've also had the Hacker B508s, C40 6s, C4012s, Lehner Basic 5300, 4200, 3600, 3100, 2700, 2100, XL5000, XL3100, XL2400, XL1600, XL1200, Lehner 1515, 1520, 1920, Feigao 10L, Plettenberg Shadow, Indoor II, Twist 42, Novak SS5800. I've tried big motors in small cars, and small motors in big cars, and from 6 cells to 29.6 volt lithium polymers and I gotta tell you, there are DEFINITELY motors that work MUCH better in certain applications and motors that just plain SUCK. The 6s motor just SUCKS for 99% of applications. Sorry, but that's my experience and plain truth. It can really be a BEAST on 6 cells IF you have the massive amp capabilities and a controller that can deliver it, but otherwise, it's a no go.

If you thought the 6s propelled hte 12L3 well, you should try a Lehner 1515 5 turn or 6 turn in that little vehicle. It's a 90 gram motor (3 ounce) and it'll turn about 70,000 rpm in your car with 6 cells. It'll take it to over 80-90 mph in 2 seconds - but you'll never find the traction!!

Check out the 1520 5 or 6 turn or C40 6s with 6 cells in your TC. You'll be doing oer 50 easily.

If you truly want to go FAST, you should try a combination of Lithium Polymer with a mild brushless but with higher voltage. That's what I'm doing in my TC4 - a 4200 KV motor with 14.8 volts runs insanely fasssst. The 14.8 volt 3500 mah weighs 11 ounces so it's much lighter than even a standard 6 cell pack.

MikeyLikesItSI · 05.20.2005, 09:48 PM

Good stuff! thanks lipomax. Definitely educational. I suppose its safe to say you have a lot of BL experience.

On a better note, it turns out what i thought was a good battery pack, must of had a few crappy cells in them (that pack has overheated a few times) and just wasn't putting out. I tried my eight cell piggy back from the 12l3 car with a fresh charge..... with the 24 tooth pinion, it just LIGHTS the tires up. Soooo..... time to throw out that one pack, and make some more.

I do however plan on running lipo's in this car more then nimh. I will run both, but the lipos will be for performance, and the nimh will be for play.

lipomaxx, i'm pretty new to lipo batteries. i know 3.7v per cell, very sensative to heat and low voltage. I have no idea what else to look for when looking at lipo's. I don't think i want to make my own packs, i'd rather just buy them. Of course i'd need something with substantial amperage. I think 14.8v on a 5915 motor with 28-30 tooth pinion is over doing it, but its going to be fun trying :-)

RC-Monster Mike · 05.21.2005, 10:14 AM

looks like you found the solution before I found the post(batteries). While I don't agree that the 6s "sucks" in most applications, there are certainly motors that will be better matched to this application. I run a similar setup in my tc3 (11.1 volt lipo with 4200Kv motor). I like the basic motors (most smaller motors work extremely well in these applications, as Lipomaxx said). For the record, I wouldn't run the 6s on 14.8 LiPos and tall gearing unless you have a lot of room and a serious controller. Also, be prepared to rebuild/replace some parts!

MikeyLikesItSI · 05.21.2005, 10:36 AM

Yeah, i'm picturing the diff gears flexing everytime i nail the throttle and hear the 4 tires break loose. Does anybody make steel gears for this? i know the TC3 TC4 and i think NTC3 all share the same diff setup.

Yeah i was more or less kidding with the 4s lipo's I'm sure it would certianly exceed this controllers amp draw (depending on the quality of the lipo). I think this 6S motor is awsome. The whole point was i wanted a higher KV motor so i can achieve a higher RPM on less cells.

Mike, can you send me a PM or e-mail when you get the expert series MGM controllers. the 120amp you have in stock, is that expert(computer programmable?)

RC-Monster Mike · 05.21.2005, 01:26 PM

The 120 amp controllers in stock are not computer programmable. The next time the 80 amp controllers come in stock, they will be computer programmable. Hopefully in a week or so.

MikeyLikesItSI · 05.21.2005, 04:10 PM

ok, whats the ETA on the computer compatible 120 dawgs?

RC-Monster Mike · 05.21.2005, 07:16 PM

Should be later this month, along with the 80 amp "dawgs" ;)

widemouthmaxx · 05.22.2005, 06:52 AM

Quote:

Originally posted by RC-Monster Mike
The 120 amp controllers in stock are not computer programmable. The next time the 80 amp controllers come in stock, they will be computer programmable. Hopefully in a week or so.

Sorry to jack your tread but since were on the subject of "computer programmable" ESC's..what are the pros and cons of this..I ordered an 80 MGM last Monday and it is not "computer programmable"....does this means its not programmable at all?

ME no understand...:o

RC-Monster Mike · 05.22.2005, 09:23 AM

The controllers are the same. Your controller can be programmed using your transmitter. The computer programmable controllers can also be programmed via a cable hooked to the computer. The computer progarmming is a bit easier. Otherwise, the controllers are the same.

MikeyLikesItSI · 05.22.2005, 10:43 AM

I believe the computer programmable one stores data too such as peak current, or peak RPM or something.

widemouthmaxx · 05.22.2005, 12:23 PM

Quote:

Originally posted by RC-Monster Mike
The controllers are the same. Your controller can be programmed using your transmitter. The computer programmable controllers can also be programmed via a cable hooked to the computer. The computer progarmming is a bit easier. Otherwise, the controllers are the same.

Ah...a little brain use doesn't hurt..thanks Mike

MikeyLikesItSI · 05.22.2005, 02:02 PM

Mike, and anybody else with experience with this controller...

Is anybody having a problem running this controller on 12 cells? I get the current over load beep 90% of the times i punch the throttle. i even programmed it to accelerate over the course of a second and a half, and it would still do it. 6S just too much motor for this controller? its really discouraging when you come around a corner, nail the throttle and it just dies.