rotor breaks a 4s or 6s?

we all use 5S mostly 1700kv and one 2000kv motor

I was using a 1700kV buggy motor on 5S.

I was at the race meeting where Marvins rotor seperated (again),it really is quite upsetting to see someone spend a lot of money on something he really believes in (electric over nitro) green issues and noise.When he built his first electric buggy,most of the people at the track we race at,really took the mickey,'the motor/esc bound to break/short/burn/explode,that sort of thing,but he stuck with it,to the extent that a few of the racers were starting to consider that he may be right in what he is doing,but with these continual breakages/problems he is beginning to get very down-hearted,which is a real shame,because this hobby needs people like him if it is to grow.He is now at the stage where he just does not trust a Tekin motor to survive a race,but because of money shortage he will have to stick with this motor,instead of,i suspect,buying a neu for his buggy,a real shame.

I'd like to know his full setup: Motor, gearing, battery, car, weight of the car,etc.

Is it possible to get a full refund for a RX8 1700 Truggy set which I bought from amain hobbies this month ? (The ESC is on the way to tekin for replacement)

I don´t want to put this set in my car anymore.

break more easily buggy 2.8" or 3.0" motor truggy?

motor 3.0" should be stronger because they are longer! or not?

Originally Posted by TekinTeamMgr
There are a few areas that we've seen cause failures. We are considering all possible options for repair along with sending out a new board as an option. The problem stems from really needing to see the unit in hand to verify operation of both board assemblies. ON the rare occasion both can be bad, one causing the other to fail. While this is rare it would be quite dissapointing for the consumer to be sent a new board only to find out that his unit is still non functional after the repair.

The most common part to have a cold solder joint is the large black piece suspended from the lower boards. It has two joints that attach it to the board and must make contact. While flowing them again isn't overly difficult it still might not be the only issue.

A broken unit is a lose lose for both sides. However we're obligated to make it right and we're doing our best to turn the service items around as quick as physically possible. We have people working on the weekends and at night to make this right for the customers experiencing the problem.
__________________________________________________ __________________________________________________ ____________

This is the component that is detached?

http://www.rc-monster.com/forum/atta...6&d=1253346648

(the B.E.C. is of type switching?)

That can be one, yes.

I was running an XB808, weighing in at 3.7kg.

Motor: Tekin T8 1700kV Buggy
Battery pack: Hyperion VX 35C 5500mAh 5S
Gearing: 42T spur, 15T pinion, 4.3:1 in the diffs.
Connectors: Direct solder between the motor and ESC, 6.5mm gold tubes between the battery and ESC.

The track is medium-large, with a few sweeping corners. EDIT: It is mainly dirt, dry and dusty - low grip. /EDIT

I use Mike's motor mount and one of his 15T pinions. In fact, the combo was bought from him at the same time as the motor mount and pinion.

EDIT:
ESC settings:
Punch Control: 60% (I believe it's around that mark. I set it to 70% on my hotwire, then lent it to someone else, so reduced it by 2 LEDs on the ESC)
Timing: 0
Cutoff: 5S
Throttle Curve: Linear

I haven't touched the other settings if I remember correctly.

I'm just not sure that the 5s 1700 setup is "ideal" but it should still work.

That's a fairly heavy car at nearly 8 1/4 lbs. My car is weighing in at 7lbs 9oz's but again, it should still work.

What rotor is in your motor? Original or the new style?

On the track how does the car feel? Do you have too much power, is your car a lot faster than other nitro buggies?

Rx8 on ebay
 

I HAVE A BRAND NEW RX8 ESC. ON EBAY NOW. THE ONLY REASON I AM SELLING IT IS BECAUSE THE 1700KV T8 WAS ON BACK ORDER WHEN I WANTED TO PURCHASE IT.MY LOSS COULD BE YOUR GAIN. JUST THOUGHT I WOULD LET YOU GUYS KNOW:eyes:

I always thought the x808 was a light buggy,certainly no where near the weight of a Truggy or MonsterTruck,are you saying there is a weight limit?
The rotor in Marvins T8 was a new V2 rotor,which you sent to him after his original V1 rotor failed.As for track running,yes the car has more initial punch,but is no faster then the nitro buggys down the straight.

Out of interest, why do you say that 5S 1700 is not ideal? It was recommended to me my many of the members here, as well as, if I remember correctly, Mike. Obviously, as the manufacturer, you're opinion/testing is perhaps more valid, but I was just wondering why?

I know it's not the lightest car, but it's only a little heavier than a nitro D8, and they don't get any more engine failures than other cars.

I have the V2 rotor in there, which was sent to me after my V1 failed.

With the 60% punch control, my buggy is a bit faster out of corners (as is expected really), but is a little slower down the main straight than the nitro buggies. Only by a very little amount, like 1/2 to 1 mph.

I turned the punch control to 60% after my original rotor failure, as I was asking what were the best ways to eke out extra run time. I turned punch control down to 70% first, then to 60%, and I find that I can't really spin it in corners any more. My 808 has got back all the driveability it had when I ran nitro. (I used to have a nitro XB808 late last year).

I now am driving smoothly, and, other than on jumps to correct the flight, do not blip the throttle. I just slowly build up the revs through a corner, and rarely brake into corners, preferring to roll into them instead.

Obviously, on tighter corners I will brake, but I do let off the throttle a coast first.

Hi mate,

I bought one of these 2nd hand off a forum user, and have a good feeling this is what has happened to mine... if i send it back, will the repair incur a cost to me other than postage??

What's the addy to post it back to for repairs?

cheers =)

I'm trying to get a feel of how the car is setup along with how you drive. I'm not saying that a 5s/1700 setup doesn't work by any means.

If however your turning down the power that much I'd suggest other changes or a different motor.

For example since your PC is down to 60% I'd say that you need to gear up a tooth and try reducing power differently. Try turning down your epa's a bit, say 90% to start out. If your car is only 1mph that a nitro car that also leads me to believe you're undergeared which can cause excessive revs and motor heat. This is not good at all and will hurt efficiency.

We're going to be faster than a nitro car. It's "how much" that is key. These motor creat so much torque that if you rev them out they waste energy and get hot.

I agree that a bit heavier than a nitro is ok. It does give me an idea of what we're working with though, and no there is no "weight limit."

The more questions I ask the better advice and guidance I provide you.

I want you to have the best experienec possible.

Please explain what you mean 210 Amps per phase?

Phase are 3, right?

then means: 210 x 3 = 630 Amp?

are also 210Amp continuous or peak?

Worst Case would be a "non warranty" replacement. Those are quite fair priced. We will need to see it to determine the amount of repair.

Would you suggest gearing up to a 16T instead? Only the very fastest nitro cars were quicker than mine, and only by the very end of the main straight. When I said that it was slower top end I meant that at absolute top speed it's slower. Having said that, you seem to suggest that even at WOT it should be faster?

I turned my PC down that far to help efficiency, not because it was uncontrollable (though it has also helped my driving). If you reckon a 1400kV buggy motor would be better, then so be it. I haven't got enough cash at the moment to afford a new motor as well as a slipperential.

Thanks for the quick turn around of the new rotor though! Top service. Just hope they last a little longer this time...

Thanks for the advice so far, I will take heed.

Alright maybe its just me. but Gearing up and down DOES NOT change motor rpm. I dont get why people keep trying to say that A different pinion will "slow down" your motor. Rpm is based on 2 factors. KV and the ability of your battery to hold voltage under load. Pinions have nothing to do with it- if your packs are not up to par however, a gearing change will equal a slightly lower rpm but moving up a tooth or two will not magically make your motor slow down..


Can any one tell me what rpm range in which the t8 motors are most efficient. I have heard around 28k rpm... can anyone confirm or deny this?

I don't think anyone was saying that, but if you are geared higher, higher gearing = higher top speed and slower acceleration. I think TekinTeamMgr was suggesting using a larger pinion to help tame the low end a bit, as the acceleration would be reduced.

Just an FYI, here is how you find loss in rpm. Take voltage/resistance to get your absolute max theoretical current. Then take the no load rpm (kv x voltage) and divide that by abs. max theoretical current and you get rpm loss per amp. (You subtract this from the total no load rpm, not the kv) You will draw more amps when geared higher, therefore you will lose some rpm. You are right that is usually small, but not always. I've tried a 20 tooth with my 1900 and it did not seem nearly as fast as the calculated 49 mph and took forever to get up to speed. At the end of the run, pack was only 110F and motor 140F. 6s with a 14 tooth was just :surprised: in comparison in terms of speed and power. Although motor temps are usually between 145 and 155 with this setup, its not like its less efficienct. It is making WAY more power with only a small increase in temps. So I would say efficiency is better described on a basis of how your geared and where you are running rather than what the rpm of the motor is. If I tried to go around the track with my 6s and use low throttle, im sure that would heat up more than if ran 4s with higher gearing.

Ok, I'm not gearing for "most efficiency" or a certain rpm range. I gear for laptimes, period.

If you find yourself turning down your system in some fashion you might be better off using the power you have in a different rev range on the chassis. This would be accomplished by a gear change. If the bottom end is to abrupt, gear it up. Electric cars should be faster ALL over the track , not just the bottom end. I've seen more people UNDERGEAR their cars rather than overgear. These motors make an incredible amount of torque and NOT taking advantage of it often shows up in motor heat, and too much current draw.

So grab a few pinions. Make a few laps, make a change. I reccomend doing this BEFORE adjusting punch control. Start with your timing advance at 10, it's a great starting point for nearly EVERY setup.

Gear for laptimes and "driveability" which is how comfortable you are with the car. If you're a smooth driver and require a smoother powerband gear accordingly. If you like your car to have snap all the time you fill find yourself geared lower than most.

The main thing is that I need to get 20 minutes on the track, for finals. That's why I haven't geared that high, have reduced timing and punch control. I have all the power I need, temps are low, and I can get 20 minutes in a final. I'm not sure how gearing up one tooth will affect that run time, but I'd certainly like to keep it.

If you have good batteries, gearing up will make the power seemingly more abrupt and aggressive - brushless isn't like brushed - brushless torque is only limited by the battery's ability to provide current, so gearing up with powerful batteries will yield stronger acceleration. If it doesn't, your batteries can't keep up. Simple as that. If you want smoother power delivery, then a throttle curve and/or punch control is the answer. I prefer throttle curves, as I find punch control to give my trigger a muddy feeling in the mid range. The better radios have an adjustment called Exponential, which works in a imilar fashion.
The physical construction, quality of materials, etc. will all determine motor efficiency - some do much better than others at partial load(such as the T8 motors, making them ideal for our use). Partial throttle is less efficient than full throttle, but this doesn't make for fast laps usually(unless perhaps you have a large oval). If you are smooth on the throttle, you will see much lower temps(minimizes short amp spikes which are not efficient). If you drove nitro for 10 years and have a habit of pulsing the throttle, practice until you can control yourself - you will see faster lap times and lower temps.
If you are experiencing high temps, it could be one or a few of several factors. Errratic throttle input will increase heat(mentioned above). Lower quality batteries will increase heat(to make the power being asked, the amp draw must increase when the voltage drops, bringing resistance more into play). You could also be over geared or under geared. Over gearing is a more common problem and more likely to cause excessive heat. Poor tire selection can increase heat(similar to under gearing). Poor soldering will cause heat. Low wire quality or too small wire size will cause heat. Poor connectors can cause heat. Heat is indicitive of inefficiency. Cooler is better. If you have excess heat, check the above things and eliminate them one by one until you have ahappy system. :)

Yes try gearing it up! If you find that you aren't on full throttle and or you find you're "not into it" as often you will consume less battery and decrease motor temps! My ENTIRE point! LOL

Try it, let us know.

Will do. Have ordered a slipperential too. Hopefully all will be here for next meeting, where I can give everything a try.

After reading your post Mike, I've done everything listed, but will try playing with gearing.

My temps are already low all round, which suggests efficiency, though it can't hurt to try.

I actually prefer punch control to throttle curves. I have a DX3R and when I first tried 1/8 BL, I tried using throttle curves (both ways) and just didn't like the feel of it. I don't have a problem with a 'muddy' feeling, I drove nitro!

Moreover, the BEC is of the type switching?

UPP!!!! :whistle:

Sorry to bring in another MFG but these principals apply to all.


I have an rx8 driving a sensorless castle 2200 (see we can all get along)
Motor temps were in the 170 range after 5 minutes of racing, geared 14/48

esc was at 3leds and batteries were at 120.

Would gearing UP bring motor temperatures down.

Its so hard to troubleshoot. Im just afraid of gearing the car up and unknowingly over heating my motor..

14/46 is what I used to run with my castle 2650 in my 8ight, even with 5s and there is no to little increase intemps over an 11 or 12 tooth. With the 2200 which has more torque due to the longer can, you should at least be using a 16 or 17 tooth pinion gear, and you will see why castle motors are generally reputed way too fast for the track.

Once again my tekin 1900 only runs 10 degrees warmer geared 20/46 than geared 14/46 or 16/46.

I was running a castle 2200. In my 8t 2.0.yeah way too fast and way too much torque. I even run mikes slipperential,still a gear muncher.i now run the 1700 tekin,and yes we can get along w/mmm on 5s 15/46.couldnt be happier, other than i could land back flips with the 2200.

I have mine in a buggy on 4s... cant get the thing to cool off.

running 60 percent punch/current limiter. 0 timing.. if I wanted to I could make this thing eat gears..... saving that for my local tracks big jump competition at in november :yes:

When i was running the 2200kv i couldnt keep anything cool i tried gearing ,timing,punch control, throttle curve,4s,5s,and the list could go on.bottom line i sold it on ebay bought the tekin system and am now selling the tekin esc. On ebay "ends tonight".my mmm has been faithfull to me. And i am very happy w/my current setup.

Just a quick Q.

Do I get some notification from Tekin Support when my ESC have arrived to their repair department or anything? I really don't want to lose the ESC somewhere in the world and the support wont answer atm.

"Gone racing.."

No, we don't generally tell you we recieved it. Hopefully you sent it with some sort of tracking ability, that will tell you if it was received.

I have to cheer this a little. I've changed my setup a little and riding style as well... here is what I run
2000kv tekin rx8 combo - third rotor in it, holding fine
5s 3300mah hyperion VX batteries
mike's slipperential with 14tooth pinion

I've changed timing to 0 and played around with throttle profile on my DX3R to give it less throttle in start and more when running fast.

I've also changed my driving style for way more smooth control over car and over throttle - since aggresive full throttle means total hell geared like this. Result:

I won 30min main among nitros, changing batteries twice. Compared to second guy who was only refueling twice too (but it took him 5 seconds, while it took me 40) this is HUGE success. Plan was to have 5000neu battery for first 14minutes, than 3300hyperion for 9 and another 3300 hyperion for rest. But after some jump that fat 5000 jumped out from car in 5.5 minutes and I have to make 13minutes on 3300mah 5s lipo while racing. So I have to smooth my driving as much as possible and I did that. Twice. Right after 30min motor was on 77celsius (170F) and ESC was running two diodes (I have novak cooling fan on it and it works great).

I know this sounds strange to be happy that my combo survived 30min main.. but reading it here and also seeing my friends going home without any racing at all, I feel it like success.

Ok, enough is enough,had a 2nd V2 rotor seperate,did'nt even get 5 minutes out of this one,had the tekin gear for just under 2 months,gone thru 2 rotors,and have'nt even got on a race track with the thing yet,totally unacceptable,i want my money back!

Seriously?!? Where were you using it? Have you changed anything since last time?

Oh, and Rich has got some I-Beams in for you at the shop, do you want me to pick them up tomorrow?

Watcha Si,yeah can't believe the new rotors gone the same as the other one,had enough of it now,say cheers to Rich for me,but got a deal on some I-beams from J E Spares.

Apart from my esc karking it with a few hard/flat landings, my tekin motor has survived very well and runs pretty cool @ around 110f...

Are you guys running direct drive? Just a thought, but maybe these motors may not like the direct drive with the extra stress it may bring? I am running the tekno clutch in my rc8 (2000kv combo - previously a 2650kv buggy motor on 4S - the 2650 only got about an hour all up, if that), and am yet to come across any problems yet, with around 3 hours drive time so far...


i am sure tekin will solve this, and actually prefer the tekin setup to the MMM - it'll just take some time unfortunately...