MGM compro + feigao 6s + TC4

[lipomax]

I still don't think it's a great motor - especially for a touring car. A touring car has a very lightweight drivetrain and tires and the extra weight of that rotor really slows performance down. A Twist 42 with 4s lipo makes my TC4 uncontrollable. It'll go beyond 60 mph with only a 23 tooth pinion and 72 spur (the diff ratio is 2.5) and stock tires. It'll spin out all 4 tires all the way to 60 mph too. Oh, to give you an idea of how fast this thing accelerates - it literally peels rubber on the concrete and you can see it in the picture. After doing a few laps around my driveway, the tires get over 170 degrees hot!

I'm thinking that the reason I can't go much faster than mid 60 mph is because my batteries won't give me more power. I need bigger lipos.... Currently using 4s 3500 mah Polyquest 12C packs.

[RC-Monster Mike]

I agree that the smaller motor perform better in the touring cars. My basic 4200 rips in mine. The fact that there are other motors that accelerate quicker in this application doesn't make the 6s a bad motor, it jsut means that there are better motors for this application. The 6s still rips, but is a touch slower off the line. I run 11.1 volt Lipos in my tc3 and it is an animal! I can turn the wheels and pull the trigger and the car will spin in the same spot like a top.

[MikeyLikesItSI]

both of you guys have pretty impressive setups. I'm not saying the 6s is king, nor am i saying my setup is perfect. But, Mike, i do the same thing with mine, spin her around in one spot, like the middle of the car is sitting on a nail.

lipomaxx, when it comes down to it, lighting up the tires is great.... but if your just spinning tires, your wasting horsepower and RPM, not to mention rubber. Maybe you should see about getting more of that power to the ground? if we sat side by side, and gunned them at the exact same time, if my tires broke loose and turned 1000 rpm, and your tires broke loose, and were turning 2000 rpm....... then who would be in the lead? LOL :L: kinda interesting when you think about it like that


incase anybody's interested

http://community.webshots.com/photo/...51258636DPfIGb

http://community.webshots.com/photo/...51258809robRFI

http://community.webshots.com/photo/...51259006fNzudm

my aluminum rims are on there way :-)

[lipomax]

I did a comparison not too long ago.. Basic 3600 vs. C4012 s (3500) and using 3s and 4s, they had the same top speed. However, the smaller motor was noticeably quicker off the line and because of the lower rotating mass, didn't "coast" as long either so it was actually more raceable. I'm DEFINITELY NOT saying the basic aren't good motors, they're awesome motors. Mike, when you say the 6s is a touch slower off the line - are you comparing it to the Basic 4200? The 6s has a kV of 5900 so it should be WAY faster than the basic 4200. I bet the Basic 5300 is faster than the 6s though despite the big difference in kV.

[MikeyLikesItSI]

Thats something really neat about the MGM, although it takes a little getting used to. But backing off from full throttle, to say, half throttle, it actually applies the breaks until it reaches the designated thottle position, its great for speeding into a corner and being able to stay on the throttle, not have to flip from the brake, and meter the throttle to keep in control.

I suppose burning up tires on concrete is like nothing but wheelies for an off road car. Its an awsome show, great bragging rights, but its not very practical for racing. Not like i'm about to join a racing league. I've been playing in the dirt for a long time (t-maxx) and this is my second onroad car (just sold the L3) in like 10 years. These high performance touring cars weren't around when i was playing on the street, so i'm pretty new to them, but its is a pretty awsome experience....

Lipomaxx: have you had any drive train problems at all? diff problems? spur? outdrives? What are you using for tires?

[lipomax]

Yes, on a dusty street, spinning the tires is no fun... but for indoor carpet racing with traction compound, it's absolutely amazing at how fast the thing will launch out of a turn. In 20 feet, this thing will go from 5 mph to 35 mph! I mean, the brushed guys are going the same speed through the turn, but then suddenly they look like they're standing still! Yes, I can still spin out the sticky tires on carpet (my eagletree was showing OVER 2 G's of acceleration) but that's why you gotta be smooth with the throttle control. You know, in Formula I racing, they can spin out their tires in first gear if they want, they have to power - they just control the power. That's how I like my RC vehicles.. I want them to have MORE than enough power and I have to control the power through throttle control and not due to limitations of HP. Now, admittedly, it's not going to give the best lap times and you won't be that consistent lap after lap, but it's a whole lot more fun to drive. Sometimes, when I catch a wide sweeping turn just right, I can powerdrift/accelerate with sticky traction compounded tires on carpet! It's NUTS to see it do that. It seems like TC on high traction surfaces are the vehicles that truly benefit from the instataneous acceleration that the smaller motors provide. On the street, it really doesn't make that much difference. Buggies and ST's really can't benefit from it either. Those vehicles don't have the traction to take advantage. Even if you did, you would only wheelie all the time.

[lipomax]

The TC4 would loosen my diff after 5 minutes of high powered runs on carpet. The diff outdrives eventually all melted and failed so I went with steel outdrive and rebuild it occasionally (the spring needs to be nice and fresh). On the street, that never happens cuz the lack of traction limits the torque on the drivetrain.

I actually didn't like that feature of the MGM and that's the reason I sold it on ebay. It causes my 2wd vehicles to spin out in a turn. Some controllers actually have "drag brake". Also, slotted brushless motors have that "drag brake" also.

On the street, I only use rubber - I believe some company's 20 compound (premounted and glued). On the carpet, purple/plaid foams or those same rubber tires. Rubber seems to be more forgiving - if you crash with foam tires, they are harder on the suspension and liable to break more parts. On street, foam tires don't stick for me. My street is too dusty.

I don't peel out on the street for fun, nor do donuts... actually after watching DualBL's video where he smokes and destroys 2 rubber tires, I did the same thing - but with 4wd. After that, I figured it was a waste of rubber so I don't do that anymore. Now it's about maximum G's of acceleration. I'm thinking of possibly doing drag racing. A lot of "experts" are saying that it can't be done with BL due to the lag time but I think it can and I think it can be very competitive. BUT, nobody to drag against here.

[MikeyLikesItSI]

lag? what is this lag of which you speak? with such instantaneous response to throttle, i don't see where there could be any lag! besides, wouldn't you have to do something to break the 60mph barrier first? i dunno if the TC4 would make a good drag car...... i suppose if you made some adapters to put much wider wheels in the back, and hike it up a little in the rear....

[lipomax]

My TC4 already does faster than 60. With 4s lipo, 23 tooth pinion, and a Twist 42, it does 60 really quickly - actually traction limited. It blows the tires all the time though.

According to the brushed drag guys, we have some millisecond initial lag where the controller tries to locate the position of the rotor. I think they're BS and that's why I wanna go prove them wrong. Those guys are not using speedos - they're using plain microswitches so it's plain off and on switch to a DC motor so they claim they have no "lag". But, the servo takes a few milliseconds to switch the switch on!

My TC4 or Pro 4 doesn't make a good drag car cuz of the inline motor and shaft. I get massive torque steer when I gun it real hard. The XXX-S G+ was a much better performer for accelerating in a straight line. But either way, I want something with a bit longer chassis to keep it more stable.

[lipomax]

BTW, I measure speed with GPS. Occasionally I pull out the old Bushnell radar gun too. That setup takes my car to 61.5 mph. BTW, using only 3s lipo, I ran my XXX-S G+ to 64.5 mph with a PUNY Lehner 1515 6 turn motor (that motor is ONLY 90 grams!!!!). The 1920 5 turn is the fastest - on 3s it was soooo fast - but I ended up busting the whole thing so I never actually got a number - but probably around 70.

[MikeyLikesItSI]

we got mixed readings from my friends bushnell radar gun, but my L3 was in the high 60's, low 70's on 8 cells.

takes millisecond to locate the rotor...... do you think that would be even measurable? please, it would be like .001 of a second. I guess they don't understand how a 3 phase motor works, and the instant torque it provides. That is one nice feature of them on machinery such as lathes and milling machines. You can snap the direction back and forth (use it to tap holes) and its like almost instantaneous. I think the brushed guys are just scared.

I've been meaning to ask what kind of GPS people are using to measure the speeds of these things, because the radar gun is too much of a pain, not to mention dangerous!

[lipomax]

Garmin makes several models. Gecko, Etrex, etc. It weighs about 3 ounces.

[MikeyLikesItSI]

I'm assuming (for instance, garmins cheapest, the etrex) records top speed?

[RC-Monster Mike]

Originally posted by lipomax
I did a comparison not too long ago.. Basic 3600 vs. C4012 s (3500) and using 3s and 4s, they had the same top speed. However, the smaller motor was noticeably quicker off the line and because of the lower rotating mass, didn't "coast" as long either so it was actually more raceable. I'm DEFINITELY NOT saying the basic aren't good motors, they're awesome motors. Mike, when you say the 6s is a touch slower off the line - are you comparing it to the Basic 4200? The 6s has a kV of 5900 so it should be WAY faster than the basic 4200. I bet the Basic 5300 is faster than the 6s though despite the big difference in kV.

The 4200 is quicker off the line when achieving the same rpm as the 6s (higher voltage). The 6s is real close to the 5300 under load (5915 is the rating with no load-under load, the Kv is just over 5300). I think the 5300 would be quicker under the same conditions (gearing, voltage) than the 6s and only a touch slower on the top. It will also draw less juice!

[captain harlock]

Hey guys, where can I find the KONTRONIK TWIST-55 motor? any thoughts LIPOMAX?