What should my next motor upgrade be, currently a Mamba Monster ESC with CC 2200kv
What should my next motor upgrade be. Right now its a 2200kv Castle motor, #1515 with a 1st Gen Mamba Monster ESC in a 3908 Clone truck. It was I believe a 3903 however everything is now equal to or better than a 3908 stock. I run a pair of 2S 5800mah 35C LiPo's in it.
I have just ordered a set of Proline Wheels and Tires, with Traxxas CVD's for the center. Axle shafts are stock 3908's. I would like to get 50+ mph out of it. However not just straight line, I want to be able to use the power, stop turn and not risk doing 20 barrell rolls. Oh the A-Arms are also RPM. Stock Shocks with purple springs. I actually pulled off the 3908 wheels and put on a set of 3906 shorter wheels and found stability went right up. Was really happy with that too.
Should I just skip the motor upgrade and drop in a pair of 3S batteries.
A pair of 3s batteries will get you there. Keep an eye on temps.
Difference between motors seems like splitting hairs nowdays.
What's your goal for the truck?
Last edited by Brokenparts; 09-02-2013 at 01:22 AM.
Probably should of gotten yourself a truggy........what your asking for requires a lot of money to put into the car.
What sort of surface are you running on and what are you trying to do? If you plan on jumping heaps thats going to go against getting it to handle around corners......
@Brokenparts, looks like 3S it is, but only for On Road Testing.
@Suteki, what I plan to do is fine the longest shocks I can find, then run soft enough springs, probably a dual rate spring, Put the springs in the Tallest holes on the arms and shock towers, then with the soft springs let it sag until the control arms are level, giving me a good flat ground stability. Run fairly thick oil in the shocks, so when I am off road, the suspension has a lot of room for downward travel if I go airborn giving me lots of hammering as the shocks return to level stance. I'll have the 2nd part of the dual rate springs very still so once the soft springs get maxed compression the 2nd set of springs will come into play and be very stiff, keeping it from bottoming out too hard on landing. This should give me an all weather E-Maxx. I have not seen dual rate springs for the E-Maxx but I am sure I can make them. Its similar to a progressive rate spring only these are 2 separate springs on the same shaft. One soft to absorb minor road issues and keep the truck smooth and a 2nd stiffer set so that when the soft set max out, it will absorb the heavy hits. As for a Truggy I have a 4x4 Stampede with Truggy conversion. Its fun but I prefer the E-Maxx due to its size and dual batteries.
Well as to what shocks you are going to use, I don't know.
One way to do it would be to use both a set of longer shocks with a softer spring on each corner and then a set of shorter shocks with stiff springs. Or you need to create a divider between the soft and harder springs on each shock. The savage has very long shocks on it from memory, longer than most buggies do. But you still cant get around the fact it is a monster truck and the wheel base isnt particularly wide vs its height.
My Emaxx virtually never rolls; I use Axial 8 spoke 40 series rims with 1.5inch offset, Losi LST 2 criveshafts with spacers to the wheel carriers which is a further 6mm offset per corner and ProLine Big Joe 40series tires with have a large contact patch that extends out beyond the wheels rim and due to its ribbed design prevents the corner of the wheel from rolling under itself.
The car is more inclined to kick up a leg slighly or simply oversteer rather than roll. The probly with such big wheels, and I assume wanting to go 50mph is gettings a drive train that wont disintegrate. The reason I said this will cost a lot of money is because i have sunk in a LOT of money into my Emaxx just to prevent it from eating itself on runs.
I have nearly got it back together now after about a year of trying everything to get it from destroying pieces everytime I drive it. Will post when / if it goes alright this time.
Other things to consider, makes yourself some way bars to help preventing the roll overs.
A bigger motor may be able to run higher speeds with less temps but you really need to ask yourself how much you want to spend?
- new motor mount
- 1/8 diffs
- custom gearing
- strong set of axles and cvds
And you would probably want a better steering setup and upgraded servos to help handle the truck at those speeds
Too help handling, I mounted the top of my shocks as far inside as I could and the lower as far outward as I could. This lowered my ride hight a bit and stiffened up the damping rate which lowered the body roll in the corners. I might try to make a sway bar setup for it.
Last edited by Brokenparts; 09-03-2013 at 07:56 PM.
I was hoping that I could stay with the stock style motor mount, or even upgrade to the E-Revo mount that puts the motor off to one side. (seen it done by another member) Currently I have the Mamba Monster #1515 2200kv motor, I thought that you could get a more powerful motor and stay with the same size motor. As to 1/8 Diffs. Those are most defiantly in my future, custom gear, I'd like to stay with my current gearing and just have a faster motor, or a motor that runs at the same speed just with more torque. Axles, well I did order the CVD's to go from the Transfer Case to the diffs. I'll give a shot with the stock axles and see how long they last.
Now as to the steering, you are one step to the left or right of me on the sway bars. I am already working on how to make a sway bar kit for the E-Maxx basing it roughly on the sway bar kit that is installed on my Stampede just running a heavier bar so it actually does some work. I have a fair bit of experience with sway bars and sizing them to real cars. Depending on weight bias and what I need the bars to actually do. A thicker front bar will help to plant the rear tires in a corner but will cause the front end to under steer badly. Adding a rear bar helps to keep the front from Under steering but will cause the rear to over steer. Its backwards of what most people think. However on the E-Maxx I think Anything, even a metal coat hanger bent into an U shape would be a major improvement. If you mount the bar tight to the frame between the chassis brace and the chassis, then connect the toe links to the top side of the control arms between the CV and the control arms, it would be out of the way enough not to catch on debris. I am 350 miles away from my Maxx's right now, so I can't work on it for another week. (I am in BC Canada till the 10th, cars are in Oregon)
Can you still buy various sizes of Piano wire at the local Hobby Shops? Might try experimenting with different sizes to see what gets the best result.
I understand a bit about sway bars. Thicker bars reduce overall grip but improve response. For steering I bought two 94773 airtonics and modified the passanger side of the chassis to run another stock spring saver. I like the idea of having the load split between two servos apposed to one big one. You just have to adjust the linkages so they aren't fighting each other. You can tell cause the servos will stop buzzing when you get it right.
Ah I didn't know you had a 3906 chassis, mine is a 3903 with the dual watertight servo's in it already. However even with dual servo's I still feel the steering is weak and slow compared to my 4x4 Stampede. Maybe I should look into better Servo's. I really need to find someone else close to me with an E-Maxx Brushless edition so I can test drive theirs and they can drive mine, just to compare handling and steering inputs I find mine has a heck of a long turning circle under throttle. I mean on rough ground with 1/2 to 3/4 throttle I can have the steering full to the right or left and its a good 40ft arc to make a 90 degree turn. That is with the shorter 3906 Tires/Wheels installed. When I had the 3908 Wheels / Tires installed, it was near pointless. It would either push the front end, or bite and flip over. Could not find a happy medium. At least with the 3906 wheels I could do a little trailing throttle over steer and whip it around. (Be hard in the corner, lift off the throttle, so it plants the front tires and reduces rear wheel traction, then punch the throttle wide open again, breaking the rear tires loose and pulling the front end in the direction the wheels are pointed) Its a great trick I learned on the Autocross course driving my Fiero. Granted I did not have the advantage of driven front wheels, but the physics are the same. Scary the first time it happens, but only gets more fun the 2nd, 3rd and 4th time you do it. Just have to remember to quickly counter steer if the back end gets a little too far out of shape.
I have a 3908 truck but it still uses only one spring from the factory. I modifed the other post on the truck to accept another spring.
Think we should go over a few basic to get around what you're looking for.
Originally Posted by Capt Fiero
So far as getting a 'faster motor the same size' it's not really going to happen, motors really are much of a muchness in terms of over all performance.
1v x Motor KV = RPM
So 1v x 2200kv = 2200 rpm.
4s = 14.8v x 2200kv = 32,560rpm
If you want to increase the 'speed' of the motor, volt up to 5S or 6S
6s = 22.2v x 2200kv = 48,840rpm
There is your 'faster' motor. Increasing RPM and / or gearing in an electric motor doesn't necessarily reduce torque, in fact from a perception stand point it may in fact increase it. Generally with electric motors you want to hang around 30-35,000, After that, you run the risk of blowing the magnets off the rotor, shattering the rotor itself or both. Castle reckons their 2200kv can handle 6S, I myself use 6S, but I rarely ever hit top speed (a monster truck like the Emaxx just is not stable enough to hold full throttle for any period of time).
By keeping the same gearing as 4s and going to 6s you will likely see a much higher top speed and more torque but definitely an increase in temps as amp draws will be higher under load. Electric motors don't really lose torque as such, they just demand more amps to compensate. Hence where you will increase motor temps (more amps = more heat) and you start really taxing the batteries.
The only way to (efficiently) go faster is with a bigger can motor (something like 1700kv), increase voltage potentially increase gearing to suit. This will give you more torque (bigger can motors = bigger rotors with bigger magnets so they don't have to use as much amps to do the turning). Helicopters and boats use very low turn / kv motors but much higher voltage to achieve the same sort of rpms due to the fact they are under much heavier loads. Same story with 5th scale RC cars.
My suggestion to you would be to increase volts, decrease or increase gearing to suit; as you won't find any faster motors because like I said they are much of a muchness so long as they are in the same kv range and properly made.
Will get to handling soon......
Bigger Motor + lower kv + higher voltage + proper gearing = crazy top speed and insane amounts of torque
Sure the smaller motors can get there but the larger motors can handle the load better and keeps them operating much more efficiently
The servo saver mod provides a stiffer setup to increase response and holding power.
Thank You Suteki, that was the most in depth reply and informative reply I have gotten so far on this forum in regards to motors and sizing. So I'll stay with the current motor and move to 6S and possibly move even to a newer ESC at a later date. Right now I still need to read up on understating waterproofing the old Mamba 1st gen ESCs. After all I live on the Wet, er West Coast, in the Pacific Northwet, er Northwest. I plan to run this thing through lots of wet rainy days and maybe even make my own Mud Pit for it.
Here is an odd question, I keep hearing people talk about Programing the Mamba speed controls, is my Mamba Monster ESC, programmable, if so, where do I get the interface cable for it. If mine is not programmable, what version is, as I really like the idea of that. Running 6s but being able to dial back the throttle response for the 1st few seconds of take off. I think I heard it called "Punch" control. Might help me with my blowing of parts.
Back to handling, I ordered some Proline Wheels and Tires, so that should help with the handling on the street and even reduce traction during my bashing sessions off road and maybe reduce damage to things. When I start playing with sway bars I'll probably just zip tie the end links during testing to see what I end up with and when I start to fine tune it, I'll look at some zero lash threaded links. Similar to a Tie Rod Ends.
Thank You Again, you have all been a tremendous help. I am a car guy and usually build, work on and tune street / strip cars. So this RC thing is kinda new to me. Hopefully I'll be able to take some of my racing knowledge and apply it to RC and get some cool results.
P.S. I know my Stampede is better suited to handling and such, but I really prefer the way my E-Maxx handles the rough terrain that I spend most of my time on. I am not sure if its just the larger mass of the E-Maxx but the Stampede seems to bounce all over the place where as the Maxx just sails over all the berms.
When it comes to handling there are a couple of things you need to decide so far as components are concerned and then the tuning to them.
Basic rule of thumb;
Harder setup: reduced over all grip, increased stability at speed / during steady state cornering, increased response, less forgiving with bumpy / uneven terrain.
Softer setup: increased over all grip, more body roll / weight transition means less stable at speed and high speed, forgiving with surface changes / uneven terrain.
Handling is all about a couple of things; surface, lateral grip and weight transition; they are all interlinked. Obviously downforce doesn't play much of a part here......unless Adrian Newey designed your RC cars body shell, then it might.
What you were talking about earlier with lift off oversteer; that is a pretty good thing to look at in terms of how the vehicle will handle.
Lift off oversteer is a technique that uses weight transition to overcome the rears lateral grip. Under acceleration a vehicles weight transitions to the rear, providing more grip to the rear; when you 'lift off' the accelerator the momentum of the car changes and the weight shifts to the front of the vehicle, increasing available grip to the front wheels, lessening grip to the rear which is why the front wheels will 'bite' in preventing the front from understeering as the grip at the front exceeds the grip at the rear, meaning the rear end will be easily overcome by the lateral forces applied when turning, causing the car to 'oversteer'. By applying the throttle again, the weight shifts to the rear again; allowing the rear to gain traction.
Weight shift changes where lateral grip can be most achieved. This is where harder vs softer setups come into play. A stiffer setup allows for less weight shift and lateral grip; this makes it more predicable at higher speed and during long sweeping corners as the lateral forces being applied to the vehicles momentum is resisted, making the car more stable as it won't suddenly change where the grip is coming from. The downside being that as the car resists weight shift, it will more quickly find it's lateral grip limits.
Conversely, a softer setup allows for greater weight shift and lateral grip. Allowing the vehicle some ability to pitch or roll under lateral forces, taking some of that force off the tires themselves. Downside of that of course is the car becomes less stable, as weight shift changes where lateral grip can be achieved most. Braking? Most of your grip is at the front. Accelerating? Rear. Cornering? On the outside of the vehicle. Braking and turning?? Front outside wheel.
So with a softer setup you can achieve greater grip, the grip isn't necessarily as static and is constantly moving in relation to where the weight shift is occurring and how you respond with your inputs.
All the above is also measured in how you have your differentials tuned. Under hard acceleration out of a corner, a heavier weighted oil in the front diff will 'pull' the car forward as both wheels spin looking for traction. This will give you less steering out of the corner but allow you to be more aggressive coming out of the corner. If you have a thicker oil in the rear, this will drive the rear wheels instead, it will give you more steering coming out of the corner, but could make the car twitchy and prone to oversteer as the outside wheel tries to spin at the same speed as the inside.
It's all about balance and the conditions of what you want which sort of comes back to what components you want to run.
I am starting to understand this stuff now, and now I know, I need to ditch my VXL system or drop to a deeper gear. I have been running 3S on it and after a few hard off road runs, grabbed my thermal gun and the little display read a rather scorching 217F for the motor and I believe 234F for the ESC. (or vice versa) Either way I was warned on here that running 3S can get the motor to overheat, so I took my thermal gun out and checked it one day. Turned out that what I thought was the battery cut off on the ESC for the Low Voltage on the LiPo was in fact the Overheat Thermal Shutdown. So every time I ran it, and I thought the battery was dead, was actually me torching the poor Stampedes VXL system. I never knew this, as I got both the Brushless E-Maxx and Stampede on a package deal trade for an Assault Rifle and lots of Ammo I no longer needed. (I've gotten past the point where I feel the need to shoot through someones engine block or through there house and out the other side.
Originally Posted by Brokenparts
Now your Servo Saver Mod, do you have pics, a build thread or other graphic illustration some place. If I can get my E-Maxx steering anywhere near as quick and (oh whats the word) Uhm, Precise as my Stampede, I will be ecstatic. I love the Stampedes steering, when you turn the wheel even from a stand still, its quick and moves lock to lock with ease. My E-Maxx kinda goes Uuuhh, Maybe, then moves about 20% of travel until I pull it forward or backward a little bit.
Traxxas has a strict language policy. A word filter operates to change inappropriate words to *s. When you see these in your post, you MUST edit them out.
Last edited by ksb51rl; 09-20-2013 at 08:05 PM.
Capt check my other thread; Emaxx Lives Again and have a look at the pictures and the video to get a better idea of components used.
Next part is about what components you want to go with.
I mentioned previously I used Big Joe 40 series tires on Axial 8 spoke wheels. That is not just a cosmetic choice, there is a reason I went that way.
The overall offset (total width) is considerably wider than the standard 3908. Just have a look at it in the video as it's driving toward or away. It's as wide as it is tall.
Coming off the handling post, the Emaxx being a monster truck allows for huge amounts of weight shift. It has a high center of gravity and roll center. This is why it rolls so much. It can actually generate a lot of traction to the point where rather than exceeding lateral grip, it actually just rolls over instead.
Rather than lowering the vehicle considerably, I simply made mine wider. By being wider, the center of gravity and roll center is changed. The roll center on my vehicle despite being as high as it is, is very very low. As the roll center is so low, the higher center of gravity effects the vehicle less as it is much harder for the lateral forces to force the car to shift it's weight due to how wider it is. There simply isn't enough 'roll' in the vehicle to cause it to flip over, so instead it exceeds it's lateral grip and oversteers or understeers depending on where the weight shift is.
As I haven't changed the overall length, lift off oversteer is still very possible and you'll see in the vehicle its basically all I was using to get it to turn in the small area I had. It didn't always work, as the large amount of grip I can get from those tires on grass I wasn't able to overcome the rears grip every time, but on a bigger field where I can run it to a higher speed before using it and I guarantee it will do it nearly every time.
I believe this is the direction you wanted so face as handling; my car is very forgiving, it is wide and able to turn at high speed without just pitching and rolling over, it instead progresses into steady states of understeer or oversteer, depending on how I react to it and what I want it to do.
The thing is, to get it to that state required the bigger tyres and offset which wasn't really all that cheap, but the expensive part? Building a drive line that could handle those tires and 6S. It is expensive and I guarantee you will be breaking a lot of parts getting it to that point, which is why I initially asked what you wanted to really do with the vehicle.
The easiest, cheapest method of controlling that weight transfer right now to get the vehicle to do what you want it to do is to install sway bars. Softer on the front, stiffer on the rear. That will give you front grip and allow the vehicle to kick it's rear out.
Generally for racing it would be the opposite, but imo copious oversteer is so much more fun than understeer......
Forget everything you know about engines, an electric motor is virtually the opposite of what you're expecting.
Originally Posted by Capt Fiero
Also, lay your rear shocks out as far as possible. Shock tower, inner most mounting hole, on the arms, outter most hole. Forgot to mention that. This will make the rear shocks harder to compress and resist weight transfer left to right and right to left.
How I got the most speed out of mine was I put a 29 pinion and a 30 tooth spur thing does stupid speeds now with some 2 2s. The guys at the LHS predicted it was going to be doing around 100 MPH if I upgraded my batteries.
Did he alao forsee magnets throwing themselves from the rotor after the kevlar bonding on them melted?
That pinion / spur ratio is almost 1:1, might as well keep a motor and esc handy as you will change them more often than you will batteries.
Suteki i did not forsee that but normally dont try and over run her. And planning to get a cooling fan for it though. Plus put holes in the body to let air circulate so it doesnt stay too hot. Im trying to keep the temps as low as possible yes i know that it is something that normally is dangerous for the engine. However i wanted to see if it will get it up to speeds that are insane.
RC Turnbuckle Jr.
If you do decide to upgrade motors or something I considered this motor not sure of the claims of 4-9s though but leopard motors are good. http://www.rcecho.com/LEOPARD-RC-Mod...tor-IM151.html
I was told it would be a direct fit same as the castle 2200kv motor. you may want to consider even on this or the motor you keep to upgrade motor bearings with the increased speed and heat build up you want them in good condition.
Mike which bearings should I use?
RC Turnbuckle Jr.
off hand I dont have the part numbers they are made i think from rcboca or acer i think but avid should sell them too i'll have to look for the #'s. A friend here changed his out not easy to do but he said it is better with better bearings than stock. I'll see if i can message him and if he still has the #'s if i cant find them. I'll post back.
Originally Posted by Gaby7192
Originally Posted by Capt Fiero
Sorry it took so long, I had trouble getting the truck apart after I thread locked everything. On the passanger side of the chassis there is a plastic post that the steering rack rides on. Youll have to shave it even with the chassis and use another spring setup, like the stock one on the drivers side of the truck. This will provide you with a stiffer connection between the wheels and the servos but it will also be less forgiving to your electronics so it is recommended to upgrade your servos while doing this.
Last edited by ksb51rl; 09-20-2013 at 08:05 PM.
RC Turnbuckle Jr.
got the bearings for the castle 1515 motor
Originally Posted by Gaby7192
Castle 1515 size.
These will work for my XeRun HW 2000kv motor as well which is nice
I am going to have to note these numbers for the bearings, as now that I have found a totally kick butt perfect setup for my driving style with my E-Maxx I can run multiple sets of batteries through it without breaking anything. (a huge step forward for me) I went bashing for nearly 2hrs today and came home with a running truck. I can see myself killing this motor or the bearings at least. Only running at a baby 4S at the moment, but time to try 6S. I found out I am geared really low, finally got the pinion off, running 65/20 however while putting it back on I wanted to make sure it was tight and snapped my allen bit off in the pinion. (tried to drill it out, didn't work, tried to use reverse (right hand bits) tried screw extractors nothing would touch the hardened allen bit. So I said screw it and left it on and been running it hard kind of hoping it would come off on its own. LOL. However back to bashing.
65/20 gears with the 6.25" tall tires, 4S 5800mAh LiPo's and finally a Wheelie Bar, man this truck is running amazing. I installed a whole slew of RPM parts and Traxxas CVD's changed shocks so no more bent shock rod. I really wish I could have gotten it all on video, but I was alone and frankly having too much fun. 6S is going to be wild. I'll start a "Muddy Maxx" thread in a bit with pictures of todays driving.
RC Turnbuckle Jr.
had that happen before with the pinion lol, try heating it up with a heat gun or something that will get it hot just on the spot and try the extractor again it might help loosen it a little to get off. i had to drill mine off made a hole larger than the screw hole though i could have used the size it was but bit broke so next was larger only hey it worked pinion was no good anymore but there cheap enough at about 5-7 each not like a motor frying