Choosing the Right T8 for your Buggy/Truggy

[jasonwipf]

Based on real life testing, racers opinions & testimony on this forum and many other forums I have put together a chart to help new people decide which T8 Motor (or any brand with similar KV ratings) might suit their needs. As well as avg. mah/min to help some determine what size packs for what situation might be needed. This is only a "general guide" so please feel free to chime in comments to assist in its tweeking.

http://i127.photobucket.com/albums/p134/jasonwipf/T8guide.jpg

[Marvin]

I think I'd agree with that overall.

Only thing though; I wouldn't use a truggy motor in a buggy, they are just too big and heavy in my opinion for buggy use.

[gnr racer]

Im sorry i dont undrstand that chart. im looking to convert my 8 2.0 buggy to electric, im pondering over a 2100kv or 2400kv, im guessing the 2100 would be ample as the 8e comes fitted with that as standard. im yet to research this forum yet for advice

[DCM]

you go for a lower KV and a higher cell count, you get better duration, and temps.

You getting the Rx8?

[gnr racer]

Sorry buddy im not sure what an 'rx8' is in the rc world?? i know its a Mazda sports car if thats any help.
seems from what i've read so far i need to be looking at rc monster in the us & castle creations for a better deal in converting my Losi, then i read about slipperrentials & i thought Oh God theres a fair bit to this conversion lark!!
thanks 'DCM' so the castle creations 2200 kv motor would do me fine?

[DCM]

when it comes to motors, make sure it is sensored.

[Marvin]

Try having a read of my guide. (http://www.oople.com/forums/showthread.php?t=29316)

I know we need that thing stickied.

When you have read that, then ask us some questions as right now there seem to be too many questions for one post to answer... :D

[jasonwipf]

Im sorry i dont undrstand that chart. im looking to convert my 8 2.0 buggy to electric, im pondering over a 2100kv or 2400kv, im guessing the 2100 would be ample as the 8e comes fitted with that as standard. im yet to research this forum yet for advice

yes do the 2100. That chart isnt just for the Tekin really, but any brand with similar KVs.

I agree marvin truggy motors are heavier in buggies and while i did it once i wouldn't do it again. Some people just really want torque or they get it then tone it down for their buggy and/or use it in their truggies when they convert them so they dont have to go buy another motor or system. So thats the only reason I put it there.

[AmiSMB]

I am currently using a T8 2250 in my buggy as I had got the 1550 and 2250 for my Truggy conversion but then the club where I race stated max 4 cell only and they were doing buggies only so did not want to spend even more so just transfered everything over. Am very happy with the 2250 in the buggy even if it is a Truggy motor.

[Marvin]

I am currently using a T8 2250 in my buggy as I had got the 1550 and 2250 for my Truggy conversion but then the club where I race stated max 4 cell only and they were doing buggies only so did not want to spend even more so just transfered everything over. Am very happy with the 2250 in the buggy even if it is a Truggy motor.

You should tell them that the 'official BRCA rules' for 1/8 electric allow 6S.

[jasonwipf]

I agree with Marvin. Site that rule and always stick up for Electric Freedoms. If they fear too much power with higher cells in high kv motors its rather misguided since too much power or rpms really hurt your ability to control the car.

Electric has really grown alot in the last 2 years in the U.S. and this year is a pivotal year for us. Growth in 1/8th electric is expected to be much greater than the last 2 years combined and with that brings about more competition about rules and bickering with the gas guys who in may clubs and organizations are starting to use politics and tricks to repress us and make us unviable for racing. What i mean is an actual effort to get some to switch back to gas in the racing scene.

Eventually Elec 1/8th will overtake gas 1/8th due to ease of operation, indoor winter racing, long-term cost savings and even for environmental reasons. So keep supporting each other and growing our ranks.

[Marvin]

You forgot the most important reason for 1/8 electric! It's faster!

[gnr racer]

Thank you guys especially Marvin for the brushless guides written on here, turns it all into a 'bit' less of a minefield although i am still a little confused with some of the math involved in it all but like i said it is all a little clearer now. I have decided to go with the 1800kv motor, v3 speedo & Hyperion lipo probably the vx 5500 5s.
there are lots of 2200kv combo's on flea bay but none of the 1800 combo.
I have emailed Mike at Monster rc as they dont list an 1800 kv combo so i am waiting for a price on that.Thanks again guys im sure i will be back again for more info

[Marvin]

The 1800 is not officially released yet as a combo - I'm sure Mike might be able to give you an ETA.

The Hyperions are good - I have one of the VX 5500mAh packs myself (5S), I like charging at 3C, it's good fun charging from flat in 20 minutes...

[jasonwipf]

Ya they have been saying that 1800 is coming out for awhile now. Well you can also just get the Tekin 1900 combo. Its costs a little more but the extra features make it well it well worth it. Smooth sensored throttle band, on ESC tuning, small footprint, highered amp capacity than the MM, clean new design and the 1900 motor is just awesome. Runs so cool too. Last October I ran it in a 4 hr enduro and it never got over 54 deg C.

[Marvin]

Main problem I had with the Tekins is the weak rotors - between me and my uncle we went through 4 in about a month and a half - ended up with us both being sent 3 replacement rotors each 'just in case'.

[jasonwipf]

Main problem I had with the Tekins is the weak rotors - between me and my uncle we went through 4 in about a month and a half - ended up with us both being sent 3 replacement rotors each 'just in case'.

once they fixed it are they slipping as of today? I ran that 4hr enduro with a rotor that slipped and I put green thread lock on it before the enduro and still runs solid months later.

[Marvin]

3 of those were the 'updated rotors'.

[jasonwipf]

Ya i spun an updated too, green thread locked same motor and 4 months now with about 100 hrs of run time and no problems

[jasonwipf]

/bump, updated chart with milage avgs, mostly from users in the u.s.

[Marvin]

Um, surely that depends on the motor used?

[jasonwipf]

/bump

[ianjoyner]

Okay so in helping me understands the trade offs between different setups:

Take the truggy 4 cell starting point. Why not just get the 2000kv and gear up if you want to go faster or gear down if you want more torque. What is the advantages of going up to the 2250kv or down to the 1700kv? Assuming you want more or less speed respectively. Thanks.

[chris_dono]

brushless motors have a "range" of gearing that will work.. too far outside either of these and you'll just get the motor too hot (and eventually smoke it)

[BRS]

Okay so in helping me understands the trade offs between different setups:

Take the truggy 4 cell starting point. Why not just get the 2000kv and gear up if you want to go faster or gear down if you want more torque. What is the advantages of going up to the 2250kv or down to the 1700kv? Assuming you want more or less speed respectively. Thanks.


It took me a bit to get my head round this, it really is a battery/motor combo with a sweet spot of around 30,000rpm

With my limited understanding of it all now this is how I see it.

Higher the voltage (ie cell count of the battery) the more efficient the system will be giving longer run times and cooler temps.
So if you go for a 6S (6 cells = 22.2volts) battery you need to match that to the right kv motor.
Motor kv x voltage = RPM's so to get 30,000 from 6S you need a 1400kv motor.. Simply going up and down motor kv's with the same batterys will put you above and below the efficeint range of the motor

Truggys also require a larger sized motor (longer usualy).

Another thing I didnt really twig for a bit was a larger battery cell count does not equal more weight its down to the mah rating. A 6S 2500mah lipo is approx half (dont pick me up) the weight of a 3S 5000mah lipo


Hope that helps

[Marvin]

Sam, a 6S 2500mAh pack would be the same weight as a 3S 5000mAh pack - look at the power of the battery - 22.2x2.5 = 55.5Wh, 11.1x5 = 55.5Wh. What affects the weight of the battery (essentially) is this power rating.

Basically, it is as Chris_Dono and Sam (BRS) have said, it's to do with efficiency. 2000KV geared up will do all the things that 2200KV will do, but will take a little more power to do so. Therefore, the overall efficiency is lower.

Gearing up/down is of course the cheapest way of doing things, and with the big motors, they're not particularly fussy, unlike 1/10th motors, so the differences aren't that much.

The ultimate efficiency run is to go as high voltage as possible, retaining the same total power. This is why the national grid is at such high voltage - the current is met with resistance, causing heat build up. That heat build up is where electrical energy is transferred into heat energy - thus less efficiency, as energy is lost from the intended purpose. The higher voltage you have, the less current you have for the same power output, and therefore, the higher efficiency you have.

Gearing a motor up draws more current, whilst when using a higher KV to do the same thing, the amount of additional current required is lower.

[ianjoyner]

Thanks all that's pretty well what I was thinking.

[BRS]

Sam, a 6S 2500mAh pack would be the same weight as a 3S 5000mAh pack - look at the power of the battery - 22.2x2.5 = 55.5Wh, 11.1x5 = 55.5Wh. What affects the weight of the battery (essentially) is this power rating.



Ah now I really get to the bottom of it :D cheers marv

[spiro]

What I have resting on my workbench at the moment:

1 x Hobao Hyper 9E
2 x Hyperion G3 VX - 4S 6500mAh (35C)


So, gurus - if I get this chart correct, this will be a pretty good setup for my local track:

1 x Tekin RX8
1 x T8 1900 KV


Any idea of what kind of runtime I can expect with this setup?
(Provided I'm not a complete nutter on the throttle.)

[Jan Larsen]

20-25 minutes given its a 6500mah battery.

[jasonwipf]

Yep Jan is right 20-25 hard racing. That motor/esc set is what most of us 4cell tekin guys are running here in the states. If you take it really easy you could make over 30minutes with that huge battery (@ about 200mah/min).

[spiro]

Thanks guys! That means one battery change for clubraces on my local track. We have a fairly fast and long track. Finals are 30 minutes. Would be insanely cool to manage one full 30 minute final with no pitstop though. Our best tuners do 2 stops on nitro.

What's the deal with the rotor on the T8? I see mentioning of green locktite. What goes wrong, and how is it fixed with locktite? Should I be worried about the quality of the Tekin cans?

[spiro]

...also, any tips on the pinion sizes I should have in my bag'o'tricks, to cater for normal tracks? Ref my previous posts with setup. I believe the "stock" pinion on the Hyper 9E is 14. As these mod 1 pinions are a bit on the steep side, I'd rather not buy 15 different sizes just in case.

[jasonwipf]

Tekin cans are fine the rotors have a glue that can brake loose and the rotor will spin on the inner shaft. Doesnt happen very often as tekin has fixed the major problem but still happens occasionally especially if your rough with the motor or let it get very hot and the resins integrity is compromised at hot temps.

Ya that would be very cool if you didnt have to pit. Higher pinion gear on a big track and very very carful throttle (no excessive wheel spin) management and a large pack might put you over the top though.

But if you do have to change batteries you should be able to get it down to 15-25seconds. If longer your pit guy needs practice or there is something wrong with your set up that makes it hard to change battery.

[spiro]

Alright, I've gone and done it. Sold my Novak HV Pro setup, and placed the final order for Tekin ESC/motor yesterday. Setup as of one week from now:

Hobao Hyper 9E
Tekin RX8
Tekin T8 1900 KV
2x Hyperion G3 VX - 4S 6500mAh
Futaba BLS351

I'll let everyone know how the Tekin bits performs compared to the Novak HV Pro setup. Hope to see the 1:8th E class grow into an actual raceclass soon.

[Malcnz]

Alright, I've gone and done it. Sold my Novak HV Pro setup, and placed the final order for Tekin ESC/motor yesterday. Setup as of one week from now:

Hobao Hyper 9E
Tekin RX8
Tekin T8 1900 KV
2x Hyperion G3 VX - 4S 6500mAh
Futaba BLS351

I'll let everyone know how the Tekin bits performs compared to the Novak HV Pro setup. Hope to see the 1:8th E class grow into an actual raceclass soon.

Good luck wih youre Tekin..I just got a 1350KV Truggy one from AMain and mine did the spinning rotor trick:o I thought also it had been solved but looks like some old stock but Tekin sending me a new rotor so hopefully all will be good...must have been a friday afternoon build this motor as it was also missing the sensor wire which was hopefully also sent by Tekin last week but havent got it yet and lucky I had one to use..thought I was buying the best when buying Tekin:eh?:

[jasonwipf]

use green thread lock and let it cure for 24hrs that should bond the rotor back on. I did that fix and ran a 4hr enduro the next week with the same motor and no problems. Heck I put green thread lock on even new tekin rotors now just as a preventative measure when I red or blue thread lock ALL the endbell (front and back) screws on all my tekin or castle motors.

I run the 1900 too in my main racer buggy, and it is smooth. I recently bought the castle 1800 and it runs as fast but you have to go up a tooth on your pinion to compensate for the lack of rpm. torque wise its fine. But it does get hotter than my tekin and you can feel some cogging on the low end. Since it is sensorless too once in a blue moon on a dead start the motor will stall upon giving it gas and I have to pump the throttle once or twice to get it moving (happened 2-3 times during my 1st 140minutes of testing)

Malcnz, you are buying the best in performance with tekin. But they are new and have a reliability bug or 2, luckily they will replace any faulty equipment at a drop of a hat. Their service department is committed to the consumer! I'd rate tekin and castle as such:

Tekin
Performance A+ (great motor KV combos, run cool and smooth)
Reliability B (rotor issue and rare ESC problems)

Castle
Performance A- (run hotter than tekin, KV tad too high or a tad too low)
Reliability A (only 3 screws on front endbell, can and do come loose more often than tekin and result in the can sliding off or busted front bearing, otherwise it would be a solid A+, red thread lock it and its not an issue)

Neu motors are also good. The rest of the stuff on the market I wouldn't touch. Your fine with either Tekin or Castle.

[spiro]

Good stuff J! Thanks for the info.

[jasonwipf]

Alright, I've gone and done it. Sold my Novak HV Pro setup, and placed the final order for Tekin ESC/motor yesterday. Setup as of one week from now:

Hobao Hyper 9E
Tekin RX8
Tekin T8 1900 KV
2x Hyperion G3 VX - 4S 6500mAh
Futaba BLS351

I'll let everyone know how the Tekin bits performs compared to the Novak HV Pro setup. Hope to see the 1:8th E class grow into an actual raceclass soon.

Ya Novak HV 6.5 was my first system and while it was fast I burned out 1 motor and 3 ESCs. Fans had to be on all the time or it was toast where I live (hot).

Hyper 9Es rock, you should like that combo you listed there. Your lipo packs are bit huge but heck you'll last a long time. With that much weight and if especially if you are hard on the throttle you do risk spinning a rotor with tekin. I run lighter 3700mah packs and I green threadlock or super glue my tekin rotors when they are new and I dont have any problems. In your case do that too when you get your tekin. green threadlock or (very fine) super glue your rotor by letting it seep into any cracks around the magnet and the main axle of the rotor. Dont get any on the bushings or ends that slip into bearings. then red (small amounts) or blue thread lock all the endbell screws just to be safe.

Motors do run cooler when you use lighter packs or smaller pinions. With that big of a pack watch your temps and consider running smaller pinions to ease the load and bring temps down. Tekin does run cooler than most. I run between 13-17T and 120-150deg F motor and 2-3 lights on my RX8 (125-140deg F) depending on the track. You dont want to run more than 5 lights on your RX8 (onboard heat indicator) and/or 170F on your motor*, 200deg F motor limit is wrong.

*motors can be 50Deg F hotter at the core of the rotor than they are on the outside of the can so a 170degF temp gun reading on the outside can be 220Deg F in the middle of the rotor which is thermal breakdown temperatures for glues and resins both on the rotor and in the windings of the can. A 200deg F motor on the outside could be 250deg F in the inside! Way over heated. You risk spinning your rotor, demagnetizing it, damaging your can or any electronics on the small motherboard inside these motors that control sensored activity, on ANY brand of motor.

Dont mean to spoof you there spiro, but I want you to run without incident and learn off my mistakes. :thumbsup:

[spiro]

Again, great stuff! You got me a bit worried on my batteries there, but I'll give them a go.
(Wish I had checked the weight issue with you lot before ordering them though. :eh?:)

Didn't know about the onboard templight feature. Pretty nifty!

Now, how to speed up the snailguys from USPS?

[jasonwipf]

Now, how to speed up the snailguys from USPS?

LOL na you can't. If its USPS its government run and things are always slow. Thats why many of us are not eager to get Obamacare (government run medicine), the treasury is in massive debt (truely cant afford it) and when ever the US government tries to run private enterprise its plagued with cost over runs, slowness and abuse.

[spiro]

...the treasury is in massive debt...
And that's why the US is now owned by China.:thumbsup:
(A bit on the OT side there.)

Just received the battery packs yesterday, and MAN are they a perfect fit for the H9E! Slides into the box like it's made for it, and with the extra length, it will balance the weight better that the short (normal) packs.

Here's a tip for you E-heads out there: Hyperion Europe is having a clearout sale on the 6500maH packs. check this link:
http://www.hyperion-eu.com/products/type/19
Scroll all the way to the bottom of the page and get ready to "ooooh" and "aaaah". Bought my 4S packs for 97 Euro pr piece.

[jasonwipf]

Oh I know I have a Mugen MBX6 & MBX6T but I use Hyper 9E battery trays. They are very robust. long enough to take any pack and plenty of screw hole combos I can use to custom mount them.

[Malcnz]

Thanks for the tip on the green loktight and will do that...
Tekin support have been very good..a little slow but no questions asked they are sending me a new rotor...when I got motor it had no sensor cable either so that is coming also...:D

[jasonwipf]

ya that sensor wire makes a big difference. I've been playing with the castle 1800 unsensored and the low end coging is driving me nuts.

[jasonwipf]

Folks,

I'm going to update this chart on page1 to reflect more updated stats from fellow 1/8th BL users. So chime in on your set ups and what your AVERAGE stats are. Do not put best case or worst case, just avg with the given stats provided.

Include:
Your Car: Buggy or Truggy
your Motors make and kv
your battery's: Cell count, Constant C max C and total MAH used on full run
avg time obtained on your runs
Tracks size

For argument sake I'll state a small track has 3000-6500sq ft, Medium track 6000-10000sq ft. and large track 10000+ sq ft. Multiply length x width; so a track 120ft wide by 70 deep is= 8400sq ft and would be considered a Medium sized track.

example:
I run a 1/8th Buggy
I run a Tekin 1900kv
My battery is a 4s, 35c constant 50C burst with 5000mah capacity
I avg. 17min
And run on a Medium size track.

[davepenny]

hi guys just thought id put my pennys worth in im running hyper 7 xrun 2050 motor mamber monster max esc turnigy 5200 2cell 30-40c two off gearing 13-46 and a full run around kmrc 28mins can do the 20 mins finals with time to spare hope this can help anyone and yes as people have said it takes all the hassel away from 1/8 raceing cant wait for my next meeting.:thumbsup:

[jasonwipf]

got it thanks. I need for 5 & 6s data if you guys have some!?