I just pre ordered a MEDUSA 2300kv 70mm motor . I plan on using this on 4s in my GTP . Will this be okay ?.

Peachy... with a RCM 4mm end plate you can use an RCM XL heatsink :)

Are you talking about the neu lehner plate. Does this motor need a clamp & end plate ?.

Not required for stopping the end bell from falling off like a Feigao and temps should be ok.

However it would help with stopping dirt from getting into the open end and would provide extra surface area for heat dissipation.

I run an S HS on my 50mm & mike ran a L on his 60mm - The XL would fit the 70mm perfectly with a neu front cover or be slightly too long 4mm without - Or you could use an L HS and have 10mm uncovered.

or you could just use a clip-on if required. Lots of options.

Well this well be on road so im not to sure there will be much if any dirt . I like the HS idea just not sure if the end plate is needed for on road .

So which one is better suited for a revo conversion on 4S?

36-70-2000

or

36-70-1600

I would go with the 70mm, especially if you paln to lock it in 2nd and use motor brakes.

linc, both his suggestions were 70mm. He's probably asking which one. :wink:

On 4s, I'd go with the 2000.

If you're only going to run 4s the 2000 would probably be better. If you plan to step up to 5s or 6s go with the 1600.

I've already got a pre-order in for the 70mm and 80mm 2000 KV motors, 70mm for my Hyper and 80mm for my Muggy. I'm a little unsure about using Medusas instead of a Neu, I was sooo happy with my 1515 I don't know about the lower rating of the Medusas. I guess I'll find out.

I like longer motors because they generate more torque, the more torque you have the less work the motor has to do. The problem is that they also draw more amps so you have to balance the length, KV, your batteries voltage, the weight of the vehicle, etc. It drives me nuts trying to decide which motor I want.

Thanks Brian.

James, I received the Tekno revo conversion last Friday. I'm going to keep the other revo nitro while the 2nd one will be running the Medusa 36-70-2000 on 4S with the MMM V3 (whenever I received the replacement for my V2.

The gmaxx will be my 6S setup with the Neu 1515 1Y and Luciano's 6S ESC which I received today.

I so want the 80mm 1600kv for my savage. Really can't afford it at the moment especially with the really bad exchange rate. I wonder if this would solve my temp issues with out gearing down.

Does anyone know if the 80mm is too long to fit in the new e-revo? I remember reading somewhere of a person using a KB45 XL and having to do some trimming to fit it in and those are 77x45mm. I would measure it if I had an e-revo but I don't have one yet.

The Medusa is 36mm in diameter so it'll fit. People had to trim stuff to make the KB45 fit mainly due to its 45mm diameter.

Thanks, going to pre-order just as soon as I'm done typi...

Ahh, the art of paying attention...:whistle: I would go with the 2000kv as well.

:lol: That's ok. We'll let it slide...THIS time! But you just used up your weekly allotment of 1 mistake...

I guess that I cannot post again till this time next week...

We'll see how far it would go :rofl::rofl:.

This is exactly my feeling too. Although the speedcalculator and these forums are a great help, it seems impossible to chose 1 motor and getting it right from the start, especially if your setup is different than common setups.

If I understand correctly:
- larger can motors with the same kv rating produce more torque than smaller can motors.
- lower kv motors produce more torque than higher kv motors with the same can length?

So if a have a setup geared for 40mph and I need more torque (and don't want to sacrifice speed) I could:
- get a larger can motor with the same kv rating;
- or go for a higher voltage setup with a lower kv rating/ same can length...

The larger can will provide more torque because there is essentially just more surface area. You get longer coils and thus a longer magnet (rotor) so even though it may be spinning at the same RPM, it will be able to provide more torque. Hopefully someone else can clear this up a little better.

A brushless motor's torque is largely dependant on amps. The KV rating tells you how many RPMs it will spin per volt applied, but the faster it spins per volt the more amps it needs to maintain that RPM. Theoretically, these Medusa motors are all capable of the same output (wattage) as long as they're the same size. A higher KV motor will require more amps and will drain the batteries faster while a lower KV motor will require fewer amps but more voltage.

If you're aiming for 40 MPH (very reasonable goal, according to BrianG's calculator my Muggy was doing around 45 on 5s with 40 series tires and a 2700KV Neu) and you already have your motor, it is cheaper to just get a smaller pinion gear. The smaller pinion gear will reduce the load you put on the motor, ESC, and batteries (reduce amp draw) which gives you more torque in 2 ways. The first way is you now have a shorter overall gear ratio, which is easier for the motor to turn, and the second is you are requiring fewer amps out of your batteries so if you really get it bogged down you have those extra amps to pull. If you aren't happy about the drop in speed, add more voltage. It's a good idea to aim your KV/voltage around 30-40k RPM though these motors can do 50k without coming apart (the bearings are rated to 60k, but you shouldn't need to push it that far).

This is where I get all confused. I spend a lot of time before buying a motor trying to balance out the weight of higher voltage packs with the amp output of the batteries I'll be using while trying to keep temps down. Technically the lower KV you run the better as long as you can feed it enough volts, but adding cells for voltage gets heavy and takes a lot of room. For a 1/8th Buggy or Truggy anything between 1500 and 2300 KV and 4-6s lipo (5-7s A123) should be fine though.

Sorry if I completely lost you, I just spent almost 8.5 hours at work so I'm a little out of it. Hopefully someone else can jump in and correct errors I've probably made :whip:

As I understand, if you go for higher voltage and lower kv, you can get lower capacity amp packs. With 5s5000mah packs you should get about the same runtime as with 10s2500mah packs (both setups geared for the same speed). So the weight of the batterys should be about the same.

what controller
 

What controller are you using with the 9S a123 setup. I am at 6s and really would like to move up to 9s.

Highflier

In theory that sounds about right, but I think the 10s 2500 mAH pack would still be bigger. The weight should be really close though. The problem with running 10s is there aren't a whole lot of ESCs on the market to run that unless you get an air ESC and go through the trouble to make it work. MGM has some ESCs that'll handle it but you're looking at $500+ to get one. Lutach has a 10s ESC though, it seems to be pretty good so far. Not sure what price but they seem to be great ESCs for the price.

Im looking for a few opinions, i just want to make sure i dont get the wrong motor. As some of you may or may not know i pre ordered a MEDUSA 70mm 2300kv motor to run on 4s in my GTP . Is this the right choice or should i get the 2000kv motor instead ?. I have recived a few opinions via pm's, & im looking for a few more . Thank's

The 2300Kv is good for 4S lipos as 300Kv isn't much when using such low voltage :tongue:. I would have gone higher voltage, but if you insist on 4S then it's a good motor. It'll be spinning at around 34000rpm so it won't be running too hot, but that will also depend on your gearing.

Ahh the long awaited 70 mm motors are finally almost here! The 80s are a surprise tho, I had no idea they were doing them. Also, the 2 new 60mm ones are a nice addition too.

Wasn't sure if I should make a new thread or in here. Its a motor question, so I opted to put it in here, so I apologize in advance if it should have gone in a new thread.

Anyway, I have a question for you gents. I have the following packs and run this setup:

2 x 4s1p A123 packs, and 2 x 3s1p A123 packs

Kyosho Inferno ST-RR
MMM v1 - still going, fingers crossed
15/50 gearing with a Feigao 8XL 2084kv
4s2p A123

This setup currently lasts about 13min of race style driving. This was excellent when my club was running 6min heats and a 10min main. Having now switched to 10min heats, and 20 or 25min finals, its now a pain in the ass.

With only 2 4s packs, I can only do about half the final and then run out of packs. I was thinking that if I can run 7s1p packs and get 13-15 min out of them, then I can have a pack to change for the 2nd half of a 20min race. A 7s1p 2300mah A123 pack is equivalent to a 6s LiPo (same charged voltage, slightly higher nominal voltage).

Which 70 (or 80)mm Medusa should I be looking at to achieve my goal of getting 12-15min (or higher) run times from a 7s1p pack. Also, what gearing should I be looking at? I've got pinions from 12t - 17t.

I was thinking the 1600kv or the 2000kv 70mm.
Any thoughts would be greatly appreciated, thanks guys.

Oh yea, does anyone have an idea of when they'll be shipping the pre-orders?

The 1600 KV 70mm sounds like it's what you're looking for. I'm not sure how long 2300 mAH will last you, but if you keep the 15T pinion on there you should be able to keep amp draws down. That motor is rated to pull up to 102 amps burst and 85 continuous, but with the voltage you're running I'm not sure that it will hit that kind of amp draw. In theory, with the rated wattage of the motor and the voltage you're putting to it you should be getting around 47.6 amps but don't take my word for it. If you can keep the amp draw down, that 7s1p pack should last you 15 minutes or better. If you don't mind going lipo, a 5s-6s 5000 mAH lipo might do you a little better.

No idea when they're shipping, I got my order in fairly early so I'm hoping to get mine before the white stuff is here to stay (it keeps snowing and melting, before too long it will actually stick :no:).

Again, I am not positive about the numbers I put above, just some quick math that works out on paper but could be completely different in the real world.

Hi Cdis,

I don't have any experience with the Kyosho Inferno, but I will help as much as my insight will allow.

First thing to consider, What kind of track are you running? A bunch of tight turns or long straighaways?

What top speed are you looking for? I'm sure the 70mm motors will be real powerhouses. I plan on getting a 70mm AND a 80mm myself. But in the meantime, I've been bashing around with a 36-60-1500kv version. I'm very pleased with it. I've been playing around with 22/40 Mod 1 gearing in an E Revo. It works well on 4S 20 5000mah Lipo. This yields about 23 minutes of runtime. I know this setup would be competive on the track. On 6S, it runs too hot for continous use.

I just switched the gearing to 18/40. We'll see how that does and what the temps are like. This may be the good 6S setup I've been looking for, or perhaps 5S.

If you want more runtime, pack some Lipo in there. You'll also lose some weight by doing so.

On the Monster Mamba that you have, please go to the Castle Website and update your firmware. Castle has came out with the a new version to make them live. The problems the Monsters were having has been linked to the old firmware version.

I hope this helps.

It's like comparing Apples to Sour Grapes, cdis. My v2 60mm was surprisingly efficient. They said something like mid November.

+1. Medusas are FAR more efficient than a Feigao, even if you got a Medusa the same size and KV rating as your Feigao you would notice an increase of run time and power.

I am running Medusa 60-1600kv with MMM and 6S1P A123 in my buggy. It is HB Lightning 2 Pro Evo, 14/46.

http://picasaweb.google.co.uk/Maciej...htning2ProEvo#

I have recorded 1804W and 164A spikes with ET. Runtime is around 8-9 min. 1P A123's have realy hard time in my buggy :intello:

If you want to run 70mm Medusa in your truggy you need IMHO 6S2P A123.

3.7 X 7 = 26 volts
1600KV X 26 = 41000 RPM
2000KV X 26 = 52000 RPM

Now your packs will sag based on you amp draw. Plus your looking for long run time. All that said. The 2000 will be close to the limit and the 1600 will be more in the sweet spot.

I don't know anything about the gearing but I would say that the 1600 with the right gearing is a better option.

Highflier
PS. Keep in mind you might be on the very edge of your ESC voltage.

Since I am in this thread anyways. Can any body comment on how a wanderer 2000KV 70MM can will compare to the Med 2000KV 6MM can (V2)?

Would be used in a E-maxx under 6s1p A123's (44000 RPM not accounting for Voltage sag)


Highflier
Wish I woudl have waited for the 70MM version. Funny thing is I never got around to installing the MED yet :(

Thanks for the replies guys.

The track is pretty twisty with 1 fairly long straight. Its about 340m in length - the faster truggy drivers are pulling around 48-49sec lap times.

As for top speed, at the moment, if I can just get it to keep up with the nitro truggys on the straight, but have enough juice to run for 12-15 min I'd be happy. I was figuring the same as you Unsullied_Spy, if I gear to keep the speed the same, the 7s1p packs should give me lower amp draw and similar run time to the 4s2p. Top speed is really only useful on the straight. With my nitro ST-RR I hardly ever hit WOT anywhere else on the track.

I'm attempting to use the batteries I have on hand and not purchase a LiPo at this stage as the missus has banned them from the house.

Highflier, A123 cells are 3.3v nominal, and 3.6v charged. Lipos are 3.7v nominal, and 4.2v charged. As you noted tho, A123's sag quite alot when in 1P at amp draws over about 50A. The MMM is rated for 6S Lipo so max voltage of 25.2v (4.2x6). The 7S A123's are also exactly 25.2v (3.6x7). So with the voltage sag, they should be much lighter on the ESC than a 6S Lipo.

I'm currently running 4s2p as the setup is pulling 80A peaks and the voltage sag was huge; unfortunately, the car is pretty heavy with all 8 cells in there. About 200g heavier than my nitro. 7s1p saves on some weight, and so hopefully with the higher v and lower A, the pack should last around the same time :D

I think that Wanderer is the same as my Feigao 8XL which is 2084kv. If it's the same motor, just rebadged, the max RPM is 30,000. I think the newer ones come with 50,000 max RPM bearings, but I'm not sure. With 6S A123 you'll be wayy over that. That's the other reason I was running a 4S A123 setup - I found the 5S was making the motor seriously hot.

If you want tho, you might consider swapping out the bearings in the wander to these, which are rated to 70k RPM. I was going to do it, but I figure the motor will be more inefficient than a Medusa anyway, so I may as well just get the Medusa lol.

Anyone got their 70/80mm cans yet? I put in the order almost a month ago and the suspense is just killing me :)

Still waiting on my 80mm, ordered 10/13.

Ordered a 70mm and an 80mm in late Sept. or early Oct. and haven't seen or heard a word from them. I'm hoping that it'll be here within 2 weeks.

Anyone got yet? :o I need a new motor now, and was looking at these, would be perfect. Im using the 36mm teknorc mount so neu is out of my options.

Are those Wanderers poorer than Feigaos/chinamotors?

looks like ill be getting a 80mm 2200kv for next spring. ill demote the 8xl to a winter motor since its sealed tight with high temp rtv silicone