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View Full Version : New Esc, Reciever, and Servo



Four8s
04-04-2007, 04:47 PM
I went to an R/C expo last weekend and
picked up a few mini infernos. White body
with friction shocks.

Half an hour out of the box, I realized just
how crumby the stock electronics are. So
what did I do? Hoped on eBay and bought
Hitec HS-81MG servos and Mamba Brushless
6800Kv systems.

I already have futaba fm radios with micro
recievers. Will I need to get anything else
or do any modding or in order to get the rx,
servo, and esc to work together?

JasonH
04-04-2007, 11:45 PM
You'll need some pinions to fit the new motor since the stock pinions don't fit. Most with a 2mm hole will work, provided they're the right pitch. I use an HPI Micro RS4 pinion and I know some others use RC18T pinions. You'll also want to go fairly small, like 10 or 11 tooth since the brushless motors tend to have less torque and more RPM than their brushed counterparts.

Four8s
04-19-2007, 06:33 AM
Got a 10t pinion. It dosent reach the stock
spur with an integy motor mount. I need an
extra mm to get proper gear mesh. At first
I was gonna extend the reach of the motor
mount holes on the chassis but now Im
thinking grinding the head of the motor
mount screws would be easier. Any other
solutions?

JasonH
04-19-2007, 12:17 PM
I would enlarge the holes for the motor mount on the chassis. You can check to make sure the motor mount won't interfere with anything first by positioning it on the chassis (with the new pinion and motor attached) and see if you'll get a good mesh by sliding everything closer to the diff.

Four8s
04-21-2007, 07:27 AM
I enlarged the motor mount holes on the
chassis and from there the install went
smoothly. This thing was flying, even with
the slipper slipping away. I was still able to
roll on the throttle and reach top speed
after about 20 yds. Managed to twist the
front drive shaft. Im definitely gotta buy a
heavy duty set along with oil shocks. Going
to scuff the slipper discs next.

The new servo is 10 times better than stock.
Maybe I should have spent the extra $3 and
got the HS85mg, then again maybe I wouldt
have been able to tell the difference. Im an
having trouble getting it to track straight.
When I turn right, the steering is skewed that
way until I turn left. Probably the servo saver?

The esc was barely warm and the motor was
in the high 90’s which is I think is kinda hot
considering it was less than 50 degreesF outside.
I think thats ok because I should be able to gear
up :D. I know 150F is bordering in the hot side
with sensorless 540 bl motors. Does the same
temps apply to mini motors?

The aluminum motormounts holes are threaded,
should I still use locknuts on the screws? If so
how do you thread them on?, the motor is in the way.

JasonH
04-23-2007, 12:46 PM
Cool, sounds like you're having fun.

Your steering problem sounds like the knuckles could be too tight, or something else in the steering system is binding. I would disconnect the servo and try to track it down from there.

Those temps seems fine. I don't recall specific recommended numbers (you can search here and find a ton of info) but you might want to get a heatsink for it anyway. Obviously the cooler you keep the motor the longer it will last.

Use Loctite on the motor mount screws.

Four8s
04-24-2007, 07:42 AM
Thanks,Ill go over the steering next and
dab some loctite on the motor mount
screws once my setup is complete.

I already mentioned that the front drive
shaft is twisted, now the front diff is
starting to go. Im about to replace them
with the new atomic diffs. What else I
should get to along with them. Im not too
concerned with adjustability, just durability.
I already have bearings. Are CVD’s necessary?
Ive also decided on swaping the 6800 for a
wraith 7k later on.

Four8s
05-04-2007, 03:39 PM
Took apart the steering and cleaned out all the grime. That solved the problem. Tracks nice and straight now. Thanks.

Wraith/quark combos in the mail. Im almost done with this build. Aside from Lipos, I figure my next parts order will be my last. Anyother suggestions on parts to increase durability? Are new CVDs a hop up primarily for racing or are they generally tougher than stocks?

SteveR1960
05-05-2007, 05:36 AM
Curious - what did you find problematic with the stock electronics? BTW - I have been replacing them also. Mainly because I wanted to experiment with all kinds of setups.

Four8s
05-05-2007, 06:46 AM
Since I only bash, I dont have a problem with the 2in1 esc/rx although the throttle and brake response is a bit mushy. My main beef is with the servo. Not enough speed/torque. Small debris easily got lodged in the linkage and would often jammed the steering in one direction. Often I would then to drive into reverse and work the steering back and forth to free up the linkage. After upgrading the servo I have not since then experience that problem.I figure that it has enough torque to break anything in the way loose.

I know I could have done that 4to3 wire mod but figured Id be going brushless anyways, just not so soon :rolleyes: .

Wow, I just realzed that I will be going through a stock and 2 brushless setups in less than two months.

SteveR1960
05-05-2007, 06:48 AM
Wow, I just realzed that I will be going through a stock and 2 brushless setups in less than two months.

LOL - quite the exspensive hobby - at least it is for me. Too much stuff to have fun tinkering with.

Four8s
05-05-2007, 07:31 AM
Exactly! Too much stuff to tinker with and not enough time. :(

Four8s
05-07-2007, 05:58 PM
I received my Wraith/Quark and am almost finished with the install :D . I just need to run to the LHS to pick up some powerpoles for the battery leads.

The motor mount holes on the can are positioned so that the leads on the other end hit the steering mount. I had to bend the leads back against the endbell. Kinda worried me doing this since the solder towards the end of the leads make the wire stiff. It felt like I was going to break something. Is there anyway to remove the endbell so that I can reposition the motor mounting holes?

Also I transplanted the Mamba/6800 into my sons H8. I limited him to 4 cells until he hones his driving skills a bit. I thought 4 cells would keep temps low but motor temps are still high. ESC and batterys are still ok though. Havent tried installing a larger pinion yet. Should pick up 12t while Im at the shop. Id say that the mamba on 4cells and 10t is almost as fast as the stock motor and pinion on 8cells

Had a problem with the initial programming of the Quark esc. I was about to shoot quark an email about my problem then I got the idea of toping off the battery pack I had it connected to. The pack took a full charge and after hooking it back up to the esc, the programming went smoothly. I think the esc was able to sense the low voltage and denied any further action :o .

Four8s
05-07-2007, 06:28 PM
Here She Is.

http://i116.photobucket.com/albums/o1/rustnpede/BrushlessH8s033med.jpg

Four8s
05-07-2007, 06:29 PM
And My Sons

http://i116.photobucket.com/albums/o1/rustnpede/BrushlessH8s032med.jpg

Four8s
05-07-2007, 07:56 PM
Do you see the connection between the Wraith and Quark leads? When I added the heat shrink it shrunk back to reveal about 1mm–2mm of connector. Should I redo the heat shrink or will It be fine as is?

JasonH
05-08-2007, 01:54 AM
Do you see the connection between the Wraith and Quark leads? When I added the heat shrink it shrunk back to reveal about 1mm–2mm of connector. Should I redo the heat shrink or will It be fine as is?
It's probably fine. They're not going to contact each other or anything else to get them to short so I can't imagine you having a problem because of it.

Four8s
05-08-2007, 07:15 AM
Motor/ESC runs too hot. Batteries are warm. I have tranny issues so that may be straining the motor.

I could only give about 1/3 throttle before the wheels would break loose in the dirt :D :D :D , even if I did roll on the throttle.

Number_8
05-08-2007, 09:05 AM
Could you tell me how this runs? I was looking into a Wraith and a Quark but my track is kinda small so thats why I'm running a 5400 now. Also what connectors are you using, they don't look much like Deans lol.

SteveR1960
05-08-2007, 02:08 PM
He is showing Powerpole connectors.

Four8s
05-08-2007, 03:59 PM
Yeah, they are power poles. Some manufacturers call them sermos connectors, which is the real name for them I think, correct me if Im wrong. Duratrax and Promax brands label them as powerpoles.

The instructions in the Quark manual suggests that deans plugs should only be used.

Ive always used always used power poles in 8.4v (subc) brushless applications. They are rated for up to 30a. There is some debate on whether or not they can handle more. Personally, I like deans plugs better because they are smaller, but since my son has problems with pulling them apart, I use powerpoles.

Four8s
05-08-2007, 04:38 PM
Could you tell me how this runs? . . .
I havent had a chance to give it a full test run, having tranny issues. I just gave the wheels a spin, against my better judgement :o , because I was anxious to see how much power the new setup is putting down.

Honestly I got this H8 to hop up just to wow any nitro 8th scalers and parking lot bashers :cool: . Top end and durability is all Im concerned with.


I was looking into a Wraith and a Quark but my track is kinda small so thats why I'm running a 5400 now. . .
How many cells and what pinnion are you running in your 5400? Is it "enough" for a small track? How are temps on it?

Four8s
05-08-2007, 04:39 PM
Hey look, Im not a "Newbie" anymore :cool:

Number_8
05-09-2007, 08:33 AM
Oh okay. I just got my Mamba 5400kv (it was from someone I know), but is the sticker meant to say CM-2042, or CM-2054 ?

Number_8
05-09-2007, 08:39 AM
Oh lol..didn't see all those posts by you ;).
Yeh when you use Lipo (if), your gonna have to change to Deans. I haven't given it a run yet I'm waiting for my bearings and my pinion gear. I oredered a 12t pinion so hopefully that will be good for my track, but I am gonna heatsink the ESC and motor.

Four8s
05-09-2007, 04:04 PM
I have a heat sink I want to add to the mamba 25. Do you put the heat sink on top of the existing heat shrink and put heat shrink over that, or do you strip away the heatshrink and lay the heat sink directly on top of the circutboard?

JasonH
05-10-2007, 12:40 AM
I have a heat sink I want to add to the mamba 25. Do you put the heat sink on top of the existing heat shrink and put heat shrink over that, or do you strip away the heatshrink and lay the heat sink directly on top of the circutboard?
I've done both, and used computer heatsink paste between the heatsink and ESC both times and secured it with some CA glue. I would not put heatshrink on top of the heatsink for a couple reasons. First, it blocks airflow to the heatsink and second, the Mamba 25 is already coated in a waterproof conformal coating (some sort of lacquer I presume) so it doesn't need any additional covering.

The first time I did it I stripped the stock shrink and glues directly to the board, the second I just glued right on top of the Mamba25 sticker. I don't think it makes much temperature difference. If I had to do it again, I would again leave the stock shrink intact and glue the heatsink to the sticker.

Four8s
05-10-2007, 07:12 AM
I would not put heatshrink on top of the heatsink for a couple reasons. First, it blocks airflow to the heatsink . . .
Hmm, you got a point. I got the Idea from my Bk controller
http://www.rc-monster.com/prodimages/brushless/controllers/3095lg.jpg?IctQual=100

Four8s
05-11-2007, 07:56 PM
Could you tell me how this runs? . . .
I solved my center diff problems by reinstalling the stock center diff. Hardly any torque to the rear wheels. With 8cells, 14/32 gearing and 90 degree weather, and no top after two minutes on my small dirt track the motor ran hot +/-140F and the esc was burning up to 170F:eek:!

I brought it to work with me later that night and did some speed runs in the parking lot. The thing was screaming. :D :D :D It seemd like the motor topped out too soon with temps at +/- 100F. ESC ran +/- 120. Maybe I can add a couple teeth to the pinnion.

On my track at home I was only able to run at about 25% throttle. Could that be causing everything to over heat? I think I read somewhere that running brushless systems at low speeds could damge the components. Maybe that only applies to sensored systems.

Run time was less than 10 minutes on a 8cell 1200mah intellects.

Number_8
05-12-2007, 03:18 AM
I would recommend locking the center diff with araldite, because I think that's why you aren't getting much power in the rear. Do you have a heatsink on your motor, because if you don't, get one, or if you do get the on with the fan. Also NiMH batteries don't have a lot of power to run brushless setups, especially a Wraith 7k and a Quark 33a, I would recommend getting a 7.4v LiPo.
Also, try using a 12t pinoin and the 3Racing Delrin Gears.

Four8s
07-19-2007, 07:23 AM
I got my 2100mAh 3S lipo from TrueRC (http://home.comcast.net/~truerc/ready_pack/ready_packs.htm) a while ago and it is awesome :D . I managed to melt a 3R spur on my first few test runs and then wear out both F&R ball diffs on my next session.

Dropping in the stock F/C/R diffs got me back on track, or should I say parking lot, for more high speed runs. Previously I had posted that the thing was "Screaming", I had no idea. On 3s I was flyin...Well almost. At half throtle the front end lifted off the ground :eek: . I lowered the ride hieght in front and added more preload to the rear shocks and the front end would still come up at 3/4 throttle. Looks like I need to add a wing upfront.

I decided to tape a 1oz fishing weight to the front end and try for full-throttle. After a couple 3/4 throttle passes with the front end on the ground I gathered enough confidence to go for it. As I eased the trigger further and further back, the front tires streached and I could see the front end start to hop as the air was pushing under it. Just as I grabbed full throttle, the front left tire blew out.

I was concentrating so hard on making sure that I had enough room to come to a stop and at the same time keep the buggy from going end-o', I diddnt notice that there were a few spectators that had gathered behind me. When the tire blew they all went WOAH! and startled me. I looked over my shoulder for a split second and when I looked back the brakes were locked and I was doing 360's towards a row of cement parking bumpers. I managed to clip the corner of one and that put me in a cartwheel then sent me skidding on my lid for about 20ft. Nothing broken except for a nice scabby looking thing on the body.

Im looking into a 1/10 wheel conversion. When I decide one Im going to belt the tires because even at about 1/3 throttle they balloon so much that theres almost no contact with the pavement.

I work at a Jr High school and occasionally I see this guy run his 5b in the parking lot and fields. One day he came and I had my H8 in my truck so I took it out and started meandering around the parking lot. He came over and we challanged each other to a drag race. 1-2-3 GO! . . . I was gone:cool:, he was 50ft back still reving trying to get his rpms up. :p

BRUSHLESS RULES!