Jerold's Limitless Build

[Jerold]

I figured I would start a build thread, not because I'm special or talented or will break a speed record, but mainly because the Arrma forums keep bugging me. Also I might keep you somewhat entertained with my mistakes. My self image of myself as a maker far exceeds my talent. .

And so here it starts. . . My first goal is to build a car that I can break 100 MPH in San Jose. The In San Jose is a very difficult clause, because we have way too many people and cars then add in the roads are in general mayhem. Not Manhatten pothole mayhem, just general disrepair. I'm still looking, perhaps a nice parking lot will work? If you have ideas or location please send them.

First things first I needed some info. So I went straight to YouTube and started watching Raz Shifrin. He does extremely clean work and runs fast. Oh, it looks like he's got really nice apartment in Israel too. Found some others like Innovation RC who is a little experimental and James McCoy who runs like lighting. Many thanks to all the YT knowledge out there.

From there I followed his 150MPH build and as a template, cleaned off my workbench and headed out. I'm making a conscious effort to give money to my local hobby store, thanks Norcal Hobbies. Amain gets plenty of my money and if we want local hobby stores to support us, we need to support them. So off I went and I picked up the Limitless kit, ESC, Motor, servo and some misc stuff.

Aside from some misc stuff, like tools my build list is below.

Brand	Part Number	Description	Qty	Cost	Ext
Arrma	ARA109011	Limitless Roller	1​	$399.99​	$399.99​
Castle	010-0167-00	XLX2 ESC	1​	$269.95​	$269.95​
Castle	060-0082-00	1717 1650 Brushless Motor	1​	$209.95​	$209.95​
Castle	CSE010-0149-00	Castle Link Data Port	1​	$19.49​	$19.49​
SkyRC		GNSS Performance Analyzer	1​	$79.99​	$79.99​
ProTek	PTK-130T	Standard Digital "High Torque" Metal Gear Servo	1​	$89.99​	$89.99​
RadioLink	RC6GS V2 6	6 Channels RC Transmitter and Gyro Receiver R7FG	1​	$79.99​	$79.99​
ProTek	PTK-5071	QS8 Connector	2​	$11.00​	$22.00​
CNHL	950904QS8	Battery	2​	$99.99​	$199.98​
3M	SJ3560	Dual Lock	1​	$23.99​	$23.99​
Saga	32T5MM	32T 5MM MOD-1 Saga Pinion	1​	$20.99​	$20.99​
Saga	36T5MM	36T 5MM MOD-1 SAGA PINION	1​	$20.99​	$20.99​
PPS	ppsgrub25mm30mm	Custom Motor Mount	1​	$109.95​	$109.95​
Powerhobby	PH1289BLUE	Dual Fan	1​	$22.95​	$22.95​
Ebay		ESC Center Brace	1​	$24.99​	$24.99​
		1x1x36" aluminum angle	1​	$17.99​	$17.99​
				Total	$1,547.25​

I'm waiting on

1. the batteries from CNHL
2. pinions and Motor Mount from Island Hobby
3. fans some balance leads from Norcal Hobby

 

[Jerold]

I've included some pictures to get approval from people I don't know, eh that's you. Funny how the internet works.

First hurdle is ESC placement. When you see the builds on YT it looks so easy, just move this, cut that and bam, it's done. OK it's not like that is real life.

I went with the Castle XLX2 because it's state of the art, darn near indestructible, and it has data logging. When I didn't know is just how freaking big that thing is.

In Raz' build, he cut the right side battery tray down and stuck the ESC to chassis with Dual Lock. The battery was a gensacearespammers Basher battery (157mm long) and it just barely fit. My first choice was to go with the CNHL, but they are 170 mm long, so I've got a spacing problem. I could go gensacearespammers, but the CHNL or SMC seems be a better choice by all discussions.

With some help from @Edough13, I had a plan. Buy the generic Ebay Center brace and mount the ESC there and raise the body two clicks in the rear. This way I keep both battery trays. The fall back is to use the stock brace and remove the one battery tray to make room for the ESC, then double stack the batteries on the other side.

The brace arrived and it looks fine. Figured I would stick some dual lock on it and we'd be done. OK now the second hurdle. The Dual Lock ads about 6 mm (.240") to the height, which means it won't work. There are some options.

1. Drill the base plate and mount the ESC
2. Use thinner double sided tape
3. Go off in the weeds and spend a day creating something that will probably end up in a ball of fire.

Naturally I took number 3.

I toyed with the idea of ditching the receiver box and putting the ESC next to the servo. It will fit but the moving servo arm next the wire is a little sketchy. There are ways around it but I want to drive the car this year sometime. Maybe later.

So back to the center brace and now I'm looking to save height and the base plate 3mm (.120") and it has to go. In it's place I took two pieces of 1x1 aluminum angle iron and attached them to the sides of the brace. Each piece was trimmed on the table saw to clear the center drive shaft and a bit of "custom" clearance work around the rear support. Then trimmed the sides to clear any tall battery options. I would have like to have the full width (2.4") and I "think" it will clear with the CNHL batteries but I won't know until I have them in hand. After putting it all together I should have left it, because the ESC is wider than the flat area.

Then I braised the hole mess together.

Drilled some holes for the ESC.

Done. . . for now

Next I'll be swapping the 6 10 awg motor leads to 8 awg with 8mm bullets. Why would I want smaller wires when I can have larger ones. Since my soldering is marginal it should be entertaining, it might be useless and end up in complete failure. Who knows.

 

[Taztaz]

Cool looking build.
Ive had my limitless for a few years now, and have had the esc in same location as you and and now where rx box used to be.

By the way, 6awg wire is thicker than 8awg.

When soldering, just make sure you tin the tip and have plenty heat and flux, needed for the bigger wires.


Good luck on your quest for speed.

 

[Jerold]

Cool looking build.
Ive had my limitless for a few years now, and have had the esc in same location as you and and now where rx box used to be.

Awesome pics thank you for the proof of concept. Any interference or concerns with the servo linkage/ is that reliable?

By the way, 6awg wire is thicker than 8awg.

You're right! The XLX2 comes with 10 awg wire and I'm swapping to 8 awg. I'm not sure what I was thinking, or not thinking. Thanks for catching that. I will correct the post.

My soldering work is just OK. I'm good with the little stuff, although the thicker stuff takes some trial and error. In the end it might look ugly but it will work. I'm using a Hakko FX-888D with a 5.2mm tip (the biggest I can find) and the heat cranked to 850F and rosin paste flux. Normally I have it set at 750F and 850F is a bit hot, but I figured it keeps the heat up a little better with the bigger wires. I struggle with keeping everything hot enough and juggling the wire, solder and iron. I do have the helping hands (arms) and it's useful but doesn't really push the two thing together.

I also toyed with your 2nd configuration you have, with both batteries on one side. The inspiration was from Island Hobby Nut (look at the 3rd pic), but it seemed to limit the battery length as well?

 

[Mr.Duke]

I went ahead and edited your profile to link to this build thread and give you your [Build Thread Contributor] badge

 

[Edough13]

Looks good man! I used some 3M double sided tape to mount my XLX2 and clearance was fine after raising the rear body posts up 2 holes. It's a little tight to get body on but not horrible and then I tape the sides of the body down to prevent parachuting and it from flapping. Packs will fit fine I've ran my dual CNHL 9500mAh packs with that same setup no problem.

 

[Taztaz]

Awesome pics thank you for the proof of concept. Any interference or concerns with the servo linkage/ is that reliable?


You're right! The XLX2 comes with 10 awg wire and I'm swapping to 8 awg. I'm not sure what I was thinking, or not thinking. Thanks for catching that. I will correct the post.

My soldering work is just OK. I'm good with the little stuff, although the thicker stuff takes some trial and error. In the end it might look ugly but it will work. I'm using a Hakko FX-888D with a 5.2mm tip (the biggest I can find) and the heat cranked to 850F and rosin paste flux. Normally I have it set at 750F and 850F is a bit hot, but I figured it keeps the heat up a little better with the bigger wires. I struggle with keeping everything hot enough and juggling the wire, solder and iron. I do have the helping hands (arms) and it's useful but doesn't really push the two thing together.

I also toyed with your 2nd configuration you have, with both batteries on one side. The inspiration was from Island Hobby Nut (look at the 3rd pic), but it seemed to limit the battery length as well?

Yes, they are the same trays i used.
I had that configuration for first year.
Last year and this year have gone bk to stock lipo trays and stock motor location.

I have never used a fan xlx2.
After running xlx upto 200°, the xlx2 is a dream.
The fan comes on at 130° if im correct and ive only hit that temp once or twice.
If the xlx2 gets upto 160 plus il put one back on.

Good luck.

 

[rotauq]

I have never used a fan xlx2.
After running xlx upto 200°, the xlx2 is a dream.
The fan comes on at 130° if im correct and ive only hit that temp once or twice.
If the xlx2 gets upto 160 plus il put one back on.

On my VTE2 i actually removed the fan entirely and it has not ran hot yet (with a 4070CM). But haven't done extreme runs either

 

[Taztaz]

Yh the xlx2 has awesome cooling capabilities.
I was using xlx before with big 40mm fan and temps have neen almost cut in half on my typhon.

 

[Jerold]

The Castle 1717 comes with 10 AWG wire and the XLX3 comes with 8 AWG wire. So I wanted to change everything to 8 AWG wire. The idea is that it's only as strong as it's weakest link, or smallest wires. I have no idea if it will make any difference, especially since I suspect me biggest hurdle will be a finding place run this beast wide open.

Here's the Theory
The current carrying ability of a wire is limited by resistance. The resistance of a wire (ohms/foot) create two issues. The first is voltage drop and the second is heat. A larger wire has a lower resistance and has less voltage drop which generates less heat.

Resistance is inversly proportional to the crosectional arear of the wire. Meaning bigger wire, less resistance. In this case 10 AWG cable is ~1/10" in diameter and the 8 AWG is ~1/8 diameter. It's about .025" diameter difference, big deal. However, when you do the math it's about 20% more area and more area means less resistance.

Equipment
I'm just discussing the equipment so people know what I'm using. It's not an endorsement nor do I get a nickle from any of the links. It's only information so do what you want with it. Also these are Amazon links I suggest you try you local stores first. For instance I saw in Home Depot had a Weller 1010 soldering station ready to go home today. You never know what you might find until you look.

My solder station is a Hakko FX-888D. It's very similar to the Weller above and pretty good for the smaller stuff. When I get to the big wires it was a bit of learning curve. I struggled a bit with finding the right soldering tip and heat. Ultimately I cranked the heat to 850F and 5.2mm chisel tip for maximum area. Also, a tip from Woodie, is to use a butane torch. Fire is good so we will try that too.

Removing the 10 AWG wires from the motor is pretty straight forwards. Sorry no pics on this. Basically, tin the iron tip, a bit of flux apply heat and gently tug until it comes off. Then I used some solder wick and a solder sucker to remove the excess material from the motor tabs.

The new 10 AWG motor wires needed to be longer because the ESC is on the center brace, so I couldn't use the wire's included with the ESC. Instead I used BNTECHGO 8 AWG wire from Amazon. I later aquired some Castle 8 AWG wire as well. I can't see a difference but if the whole thing explodes I will let you know.

First thing is I wanted to get the 8mm connectors soldered. I started with this, becasue the connectors are small and I can hold them while I work on the motor. This turned out be pretty easy with a bit of practice using one of two method.

Solder prep
For both methods you need to strip the wire end, flux things and tin them.

I have a fancy wire stripping tool and it works great, but you don't have precise control over the exact length. For smaller wires I just pull off more than I need to and clip the wire to length. It's not quite that easy with 10 AWG wire. You kinda want to get it right the first time. Because it's expensive and it's not easy to cleanly shorten the exposed wire.

I ended up rolling a razor over the silicon insulation and pulling it off. This way I have more control, the end comes out clean and edge is sharp.

Then I added some flux. Yeah the solder has flux, but extra flux just burns off and makes life so much easier. I found that rather than "dipping" my wire, connector or other object to be soldered in the flux I used a cotton swab. It doesn't disturb my twists in the wire and I can get into tighter places. I also tried an "Acid Brush" from Home Depot, it's garbage and doesn't work very well.

BTW the clampy looking thing is one of the "helping hands" that normally attaches to a metal plate. I have a metal frame work bench and it allows more options and can be attached above my wire.

Also note the silicon solder mat in the background. It was well worth the $18. It's made of Silicon, won't burn nor stain, within reason of course. I dropped solder balls on it all day and the just fall off. Then wiped it down with some alcohol and it's clean. It also has lots of pockets and a magnet to keep your parts sorted, cause we've all dropped that tiny screw some place. The only down side is that it's not the size of my work surface.

After a little bit if heat the wire is tinned.

Next, fluxed the connector.

Then I heated it with my soldering iron and melted some solder into it. BTW the Vise Grips are only just holding the connector, they are not clamped. Even though it's not a contact surfaceI did not want to mar the connector.

Now I have a tinned wire and a cup full of solder. The brown stuff is excess flux. It bubbles out and burns off when you heat it up. You want the cup full, but not overflowing. I did one connector where I added enough solder to flow out through the hole and down to the connector surface. Oops.

Method one
In this one I did some searching to see how other did and didn't really find much. I also started another thread about soldering and @WoodiE clued me into a Bernzomatic Butane torch.

I put the wire in my vise in a vertical orientation, the place the cup over the wire and heat the snot out of the cup. The cup dropped on to the wire when the solder melted. The little fire on the bottom is the flux burrning off. Its pretty hard to burn silicon. I cleaned it up alcohol and it looks great..

This works pretty well. If you need to add a bit of solder or clean it up you can do that with the iron. This is what I got in the end. As you can see I stripped a bit too much insulation, but that's OK it will be covered by heat shrink anyway.

Method Two
Sorry no pix on doing this one just the end result. In the method I add more flux to both the wire and the connector full of solder. Then warm them both, alternating between them with a bit more attention to the cup. The cup should look liquidy and the wire shiny. Then put the wire into the cup and get your tip in there with it. The wire will start to wick some of the solder out and the release the heat. If you need to add more solder than do it before you remove the heat.

Both methods seem to work well, but I actually think the second method is a bit easier because I can see what I'm doing and don't need to transition from my solder station to the vise.

One thing to watch for with any method is the solder wicking up the wire past your work area and under the insulation. It won't hurt anything, but it makes the wire stiff in that area and it's just weird. To avoid this use high heat for a shorter period of time. Also using a metal object (like Vise Grips) to hold your connector, acts like a heat sink and makes it harder to heat up your connector. That's why you see people use wood blocks.

I added some heat shrink and the connectors are done!

A last note on the Berzomatic torch. It has a "heat gun" attachment and it sucks or I'm doing it wrong. If I use my Harbor Freight heat gun the heat shrink would be shrunken in about 10 seconds. With this attachment its too a very log time. So it's better than a lighter, becsause it doesn't burn the material but the heat output is lacking.

Soldering the Motor
Admittedly this could use some work. Suggestion, comments or complaints are welcome.

One of the hardest things it to hold the wire in place, apply solder and a bit of pressure. So this is what I came up with.

This is just a piece of foil wrapped around the motor and wire held by a Velcro strap. I know the wire will get hot and didn't want to melt the strap, thus the foil.

I tinned the connector tab and wire. Note they are much shorter on this end, lesson learned. Cinched it down and heated with the my iron. Once everything was hot, I gave it a little bit of love with some pliers and it was done. I did add a bit more solder too.

This is the mostly finished product. No they are not touching in the back, it's the perspective of the camera. I also cleaned up the spiky bits and everything has reasonable clearance. It's not as pretty as my connectors, but it's functional an solid. Like I said I need some practice on this part.

Next up Practical Proto Solution motor mount.

 

[Jerold]

In this entry I'm discussing the Practical Prototype Solutions Motor Mount Combo. Yeah, it 5 screws underneath, 2 on top, and 2 more in front. But it's much more than a few screws.

The PPS Motor Mount Combo includes the differential cover and cap and I would highly recommend this combo over just the mount. It replaces the center diff mount along with the motor mount.

I purchased mine from Island Hobby Nut. The IHN website is a bit clunky, hard to navigate, hard to find, and it not straight forwards to find your order but they do have lots of stuff you can't find in your local hobby store or on Amain. Over all the experience was good just not Amain good. If you shop the site I would suggest just throw everything in your cart when you think you might like it and remove what you don't want in the end.

You an also purchase this and other products directly from PPS on their website.
https://practicalproto.com/collections/things-to-buy

Arrma PMC Motor Mount
The first adventure is removing the PMC mount I'm replacing. PMC stands for Pretty Much Crap and it's the stock motor mount. I'm not sure of the cost or engineering model for it, but it's not very good and that might be kind words. I should be clear, it fine if you don't ever need to remove it. If for some reason you decide to keep the stock mount, maybe you're drunk, like pain or lack the funds, I would at the very least replace the button head screws on top with a socket head screw, I've seen the button heads strip out. More on screw head depth later.

There are 4 parts to the PMC mount, not including HW which is another discussion...

• Aluminum Sliding Motor Mount
• Sliding Motor Mount Plate
• Center Differential Mount, which consists of a plastic bearing mount and plastic top cap.

Since half of that is plastic, it's all a bit wobbly and that's no good.

I first removed the top cap and one of the plastic holes in the bearing mount stripped out. Like there was plastic stuck on the threads. This was removed with hand tools, so it had to be a problem from the factory. Sorry I didn't notice that it had pulled the threads out otherwise I would have taken a picture as well. This is sort of a critical hole too, because it holds your center diff bearing that is rotating at something like Mach 12.

But I do have a picture of the bearing mount with the stripped hole.

PMC Hardware, or was that me?
Next I was removing the screws from the bottom an stripped a bolt head. Now to the bolt extractor and it just made a nice cone in the middle, which became a nice index for my drill. Good thing my drilling skills are better than my unscrewing skills. This is what it looks like after my handy work. Dang good if I do say so myself.

To be fair, this could have been my fault because I hit it with the electric driver and rounded the head. Then I used some heat to soften the threadlock on the others, just to be safe.

There is also another thread, or 3, about the quality of the screws, but I don't think this is a quality of the metal issue. These are stamped as 10.9 which (I believe) is the second strongest off the shelf metric fastener you can get. Sorry it's a bit blurry but still readable.

So it shouldn't strip. . . however.

For some reason Arrma uses a metric S#@* Ton of threadlock. Which is why you need heat. I'm not sure why they use that much, but I certainly got my money's worth.

The head depth is only 1.1mm on the counter sunk screws, which allows for tool misalignment. To put this in perspective the socket head screw have 2mm (nearly 2x) the depth and are far less likely to strip because you are less likely to missalign your hex wrench. Also socket head screws provide more surface area (less pressure) inside the head.

Remember that comment about the top button head screws on the PMC mount? This is why you want to replace them with socket head screws, they are similar to the counter sunk screws.

I couldn't get a pix of my caliper showing the depth, so here they are side by side.

The PPS Mount
The Practical Prototype Solutions Motor Mount Combo, replaces all the parts described above and lucky for me, comes with all new hardware too!

This is a mechanical work of art, precision machined and it comes in custom 3d printed case to holds all the parts securely. There was more thought and work put into this mount than one can imagine and is a bargain at $110 USD.

Aside from esthetics of the fluting and milling it's a very interesting design because there is an adjustment screw and a grub screw that locks it in. Then two additional screws on top to just make sure that nothing twists out of place. In his instructional video he shows how to install and adjust it..

The adjustment screw makes quick work of setting the gear mesh. It's fast and precise; far more accurate and easy than the PMC mount. Like if you mess up the gear mesh now, you've got a special talent.

Some of the other nice features are the M4 screw upgrade, if your motor uses them. The PMC mount only uses M3 screws which are probably fine, but why not use the larger stronger and more impressive screws or at least make it an option. I supposed the PMC mount is design to fit Spektrum motors and they probably all use M3 screws?

Also this accepts 25mm and 30mm, motors. So you only need one mount no mater what motor you choose. Unless you want two motors, which there is an option for that too.

Replacing the plastic bits with solid aluminum makes the center diff mounting so much more solid too. Given the added rigidity, I suspect that not only being a more robust mount, it most likely puts more power to the ground as well because stuff is less floppy. I'm not sure how you would prove/disprove that one though, is there a tiny RC dyno that it can be tested on?

The PPS mount is this is the first thing I would recommend adding to your build!

 

[Jerold]

In this update the we wrestle a Mamba and win!

Really though it's mostly a folly of incompetence combined with trial and error where I get lucky enough to make something work. I figured I would put it out here so y'all can see the mistakes I'm making and things I missed. Maybe it will save some time for the next guy or maybe y'all will have a good laugh at the noob. Either way I'm happy to do it.

Being a noob I have a new perspective on things that others, more experienced builders, may over look. They have seen it before and just automatically make the correction. Having never experienced this I get to make the mistakes that have been made a million times before. Don't take this entry as a giant complaint, it's just my experiance and it's there for others to see.

More soldering
With all the parts ready (I think), the cross brace modified, ESC mounted, wires and connectors soldered it's time to make the wheels turn. All I need to do is plug in the ESC, servo and a battery right, or at least in theory.

The first thing to fix is the ESC battery connector. I soldered the wrong (female) battery connector on the ESC. I've done that before and become very good at it.

First Power
With that resolved I can power the car and center the servo. Ok that is done.

This next part is mostly (spoiler) taken from another post that I had, sorry for the duplication. I added some details here for those that are interested. That post has more than 100 views with 0, Zero, Nil, nada, zip, zilch answers. That's a first. Given that it was a bit of a mystery it's worth getting the word out there, not only of the solution but how I found it. Hopefully save some time for others.

Calibration Gone Wrong... I think?
Here is what happens, I powered it up and get 4 beeps meaning 4S. The steering works. It has no go though. Maybe I need to calibrate the ESC. This where it gets interesting.

Full throttle, wait - Beeps and red light flashing​

Full reverse, wait - Beeps and green light flashing​

Neutral, wait - Beeps and yellow light flashing​

Fail - I think it's 2 beeps which is start failed.​

From the ESC docs.

Here is a video of the calibration and the error afterwards.

This doesn't happen if I just power on, only after the calibration.
Castle says:

Let's try that out. After creating a service request online with Castle Creations I got a auto-reply email that says:

Probably a reasonable response since, support cost real money and any idiot (me) can spend $400 and not get the stupid thing to work correctly. Unfortunately, there is no way for me to effectively contact them and give them an update, now that it's fixed. I would share with them what I found which might be a bug in the ESC SW or poor documentation or maybe I don't understand the features and settings. Probably #3.

I wanted to connect to the ESC with the SW and see if there is a error log or some clue. I installed the Castle Quick Connect Duo Link. I didn't realize this was a Duo link when I bought and thought it was just a single channel. With Duo, I "think" I can assign a second channel to another function like gyro or power output. Ok something else to figure out later. The wiring diagram is below.

To properly install this means putting the Aux channel wires back into the ESC connector. I had previously removed them because I didn't plan on using the aux. It's just extra wires to deal with. After the wires are reconnected and the Duo connected in the car, I went through the options and didn't see anything out of place. Updated the firmware, even though it was the latest version, reset everything to defaults and still nothing.

After hours of rechecking everything, scouring the internet, making a video and posting on the www.arrmaforum.com it occurred to me to check the battery voltage. They are new CNHL 4S LiPo and presumably shipped with a storage charge, but I didn't actually check it. My LiPo Checker says it's 3.8V/cell and 15.4V total that should work.

Back to the Castle Link SW. The ESC liPo cutoff setting was set to "Auto-LiPo". I would expect a 4S battery should cutoff, maybe around 3.3-3.5V? My battery is a 4S at 3.85V per cell (15.4V total), which is well "should be fine" but I don't know at what voltage the Auto cuts out at. Let us dig a bit more.

Sorry for the poor quality screen shot. I cannot find a PDF of the Castle Link SW User Guide. . . So screen shots you get. This is what the Castle SW Help says, which sounds like its cutoff at 3V/cell? Seems a bit low but still should work.

This is from the Castle XLX2 FAQ page

15. What Auto-LiPo Volts/cell cutoff should I be using with my Mamba XLX2?​

You should use whatever your battery manufacturer’s recommendations are. Your speed controller came with a factory cutoff of 3.2v/cell. If you need to adjust this you can use a Castle Link or Field Link to program the speed controller for anything from 3.0v to 3.5v per cell.​

So let's do some math. If my battery is 3.8V/cell and the Auto-Lipo cutoff is 3.2V/Cell I should be OK.

There are other settings in there as well and if I select 4S the cut off value is 12.8V or 3.2V/cell it's the same as the Auto-Lipo.

Let's try that and see what happens.... wait for it. It's alive and the wheels turn ... backwards.

Back tot he SW and reverse the throttle, and they now it moves the right direction. OK Done, sort of.

Test Drive
I took it outside to give it a test drive and found that going forwards sort of worked and reverse worked much better. Then when it stopped the motor chattered. It oscillated like it's sort of in between two different poles and sounded like a diesel motor.

From there I went back inside, tried recalibrating the ESC, and nothing happened. Like no calibration, OK another thing to go figure out later. Moving on I pulled up the Castle Link SW to chase my tail for a while. I tried a few random settings, max power (up from 30% to 70%) swap the motor direction again, change the timing....Finally the car did something that gave me a clue, which was it kept moving after I stopped. It's the throttle trim! I dialed that up a little bit and it works, yeah. It's only midnight and I'm out in the street, in my PJ's and flip flops but it works.

Loose Nuts
Back inside I pull the battery and check the temp on the motor to make sure it's no going weird. And the motor moved! The M4 screws for mount where loose. I'm pretty sure I put threadlock on there, but maybe not. I checked it all out an everything is good, more threadlock and back together.

I'm currently using Blue Loctite on all the metal-metal threads. Is that good enough or do I need to move to Red Loctite?

Castle Firmware Issues
I found a few issues with the Castle SW and Firmware. They may or may not be bugs. It could be me not understanding what the expected behavior is. I dunno either way, but it took a bit of time to figure it out.

1. The Auto-LiPo cutoff features doesn't work with 4S. Maybe other S's too but I tested with 4S and it failed. It was recognized as 4S and the battery has a charge of 15.4V, the cutoff should be 12.8V, but it cut me off anyway. Why?
2. The error beeps After calibration. It gave me ● ● (two short beeps). This indicates a start failed, which is not the case. It is a low voltage which should ● ─ (short beep, long beep). I'm not even sure what a "start failed" is? There is no documentation on it.
3. Document what a Start Failed error means and how to address it.
4. After power on it gave me no errors at all? If it wasn't working because of the Auto-LiPo setting detecting a voltage too low, it should give me an error.
5. No error codes, feedback or diagnostics in the software. Part of having a log file is to record data, that would (should) include an errors or conditions encountered that would cause a malfunction.
6. PDF Please! Having the Castle Link SW Manual in a concise PDF for reading would be so useful!!!! Walking through the tools, which must be connected to an ESC to see all the options is just painful. This is very basic stuff and no one with modern SW buries the documentation in the context of each individual feature. It's clunky, difficult to navigate, you have no control over the tiny little font it uses and you cannot copy and paste to anything. There is no excuse for this, just fix it.

There are very few companies that can do everything well, none the less perfect. Castle is one of them. There hardware seems to be good, probably the best out there. They also provide a SW link for custom programming and setup which makes it about 100 time better than the Traxxas TQI feature tree. However, from this experience I can see more time was spent developing the motor and ESC than the SW and the help files.

 

[Jerold]

I was able to get the sensor wire to just barely fit. I will probably get another one and splice it together to hide it out of the way somewhere. Another project for another day.

With the sensor wire the throttle is so much smoother and I don't feel like I'm launching a rocket just to get it moving.

A few very short videos.

Just for reference in case some else sees the same thing. This is the chatter I was getting from the throttle trim being off. It with the sensor wire in so it is much improved from the without the sensor wire.

The next two are of the front and rear drive shafts. They wobble like a wonky shopping cart wheel. The car is brand new, never been crashed nor over 18 mph.

Front Drive Shaft Wobble

Rear Drive Shaft Wobble

Are they usually this bad from the factory?

 

[Jerold]

Fire with a side of disrepair

Okay it wasn't a full on blaze but a bit of a mucked up connector and cheap lesson.

Last weekend I was going to push through and finish things up so I can run the car a bit on some shake down runs.

Sensor, ESC and AUX wires
I was all set to start extending the sensor wire. Soldering iron in hand, I figured I would give it one last shot and the sensor wire just barely made it around the other side of the brace. In hindsight, I should have mounted the ESC a bit more forwards and it would have been easier.

I ran the ESC and AUX wire under my mounting plate and added some electrical tape to take the edge off. It's not a proper grommet but it will work. I also had to take the extra "mounting holes" off the top of the rear support brace to make room for the wires. Then I mounted the On/Off switch with a touch of Dual Lock. I think that's going to change in the future. It's not very stable. Maybe I will make a little mounting plate and attach it to the center brace?

Another angle. My Battery connectors are sort of long and I'm still figuring out how to stuff them in there. I think they battery leads would be better off up front which means end swapping the ESC, and it also makes my sensor, ESC and AUX wires much easier to route. But I will need to extend my motor leads. Totally do able . . . another day.

BTW that's my 4S jumper on the mat not some weird battery.

Alignment
It was super F'd up when it came out of the box and wish I had some pix. Sorry I messed that one up, put it on the list.

First a huge thank you to everyone that contributes on ArrmaForum and YT. Even though it took a while, it was great having virtual mentors to walk me through the adjustments. The alignment is complex and everything changes everything else. My method is simple, take your time and check it 3 times. Eventually it will come out right.

This is also a useful article from TireRack.
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=4#:~:text=Toe can also be used to alter a,especially during initial turn-in while entering a corner.

First thing is setting the ride height, which was pretty easy compared to most other things. There is a trick that Raz used in his video, where you drill a hole in your control arms to get to the adjustment screw. I cranked the spring preload all the way down (max height and max stiffness). then set my height so it's about 1/2" off the ground at the splitter.

Next up was the toe setting. Toe is measured as the different in distance between the front and rear of the tires. On a full size car it's fractions of inches. So I have no idea of what it would be on the Limitless maybe 1/8" of 1/7 scale? Eh that's .017". Isn't that pretty much straight? I dunno. Right now it's got a fair bit of front toe in which I probably need to straighten out. I don't want toe out because it makes the steering more sensitive, and I don't want that. More wrenching later. BTW if you change one setting the other change with it. So it's a circle of wrenching.

On to the Camber. The goal is 0°, i.e. dead vertical. If I was cornering I would want negative camber where the wheels lean inwards, but I'm not planning on racing it so it's good straight up to maximize the tire patch in a straight line. I used Speed Square as my guide. This works very well because it sit flat on the table and give me a vertical edge to align the wheel to. The painful part is the adjustment. Take off the wheel, loosen the cap screw, tweak the screw, tighten up the cap screws, make sure everything moves put the wheel on and check it. Repeat. It also changes the ride height a little bit because of the angle of the wheels to the road and your toe.... and the circle continues.

I didn't adjust the caster. Mostly because it seems like it involves more time than I have at the moment. To do that I would move the spacer from the back of the upper controller arm to the front. This will increase the caster (lean it back) and help with high speed stability and tracking. The down side is it take more steering effort, but my servo is good and it shouldn't be an issue.

Rear suspension
This has less settings and is easier. The turn buckle on top controls your camber, which should be 0° as well. The ride height is good, just crank down the shocks and add my "bump stops" to reduce down travel.

My "bump stops" are nitro tubing over the rear shock shaft. The tubing reduces the squat on acceleration and keeps the rear end higher than the front. That's important if you don't want to take flight.

Ok this is a really a pain in the butt!! The first one I managed to accidentally dump most of the shock fluid. Lesson learned for the next one, I dumped the fluid to the first one. Nitro tubing installed and more fluid on the way.

Other stuff
While you're doing the camber, you can theoretically increase the track width by pushing the top and bottom out. It might take out some of axle & hub slop. Or something different. We used to use Speed Rings on our skateboard bearings to give the nut and the truck end a surface to contact that was not the rim of the bearing. So I'm thinking I can do the same thing and add a shim between the hub and the bearing (speed ring) to get rid of that slop.

The next discover, is I figured the tires would be not balanced, but they are actually no even round. This explains why people run foam tires and shave them down.

It's amazing to me the wheels don't fly off into a million pieces. Oh wait the do.

The Test Drive, New PB, maybe a World Record?
I vacuum it out, blow out with compressed air, hook up some batteries and we our ready to roll. Finally!

I ran it around in front of my house and reach a new PB of 16 MPH. I'm pretty that's a World's Record for the slowest Limitless on the planet.

Looks good, drives straight, it's not too loud, sounds good. But it didn't really run quite right, it was cutting out, had a "radio glitch". I pulled the lid and noticed that it smelled bad.

That's when I learn another lesson that day. It's easy to not fully seat the QS8 connector completly. This was the result, a mucked connector. I tried a nylon bruch but it didn't do much. I also have brass and steel but I'm pretty sure if it cleaned the connector it would ruin the coating.

Really it's just a couple of connectors - no big deal. But it was disappointing and then the reality set in. This thing, my Limitless child could burn to the ground. That would suck.

I'm used to running 3S on my crawler and SC truck. But 8S is no joke, there is a lot of potential energy in there.

Since I also broke the lawn mower that day too, I figured I would set it aside and fix it later. I've done enough damage for one day.

 

[Jerold]

Constantly Learning
Today I fixed the connector burnt up connectors. Unsoldered the ESC wires, because they are dead and if I short them out it doesn't matter. I just cut the battery connectors. I really hate soldering batteries connectors, it makes me nervous. Having a healthy respect for them as tiny little bomb probably helps.

After everything was fixed up. I took a look at the factory CNHL connectors and, yeah I use way too much solder. Or maybe they don't use enough. I think it's the first. The joint looks solid and very little solder past the connection.

Running low on daylight I took it out front for a quick test and got a new PB. Keep in mind this is like a 50' run on a crappy road, with a single 1/2 charged 4S LiPo.

Hopefully this weekend I can give it more solid run and see what we get.

 

[LibertyMKiii]

Very informative posts. I would say that those CNHL didn't have enough contact area as the wire was not pushed all the way in either.
There was another thread on that here on the Arrma Forum about how CNHL does a lazy job on the soldering.

 

[1coopgt]

Constantly Learning
Today I fixed the connector burnt up connectors. Unsoldered the ESC wires, because they are dead and if I short them out it doesn't matter. I just cut the battery connectors. I really hate soldering batteries connectors, it makes me nervous. Having a healthy respect for them as tiny little bomb probably helps.

After everything was fixed up. I took a look at the factory CNHL connectors and, yeah I use way too much solder. Or maybe they don't use enough. I think it's the first. The joint looks solid and very little solder past the connection.
View attachment 205160

Running low on daylight I took it out front for a quick test and got a new PB. Keep in mind this is like a 50' run on a crappy road, with a single 1/2 charged 4S LiPo.
View attachment 205161

Hopefully this weekend I can give it more solid run and see what we get.

That's not enough solder. That cup should be full of solder to the bottom. And the wire should really reach to the bottom of the cup also.

 

[Jerold]

Very informative posts.

I was a little mixed about how much detail to include, because no one will read it if it's too long. But in this case, it was mostly selfish reasons. My thought is that at some point I won't remember what I did or why and it's a good place to keep it. Also I might I save a little time for the next guy.

I would say that those CNHL didn't have enough contact area as the wire was not pushed all the way in either.
There was another thread on that here on the Arrma Forum about how CNHL does a lazy job on the soldering.

Agreed. I'm sure that we (I) typically use way too much solder but that seemed a bit chintzy. I think the best reason to fill the cup is to make it stronger.

 

[LibertyMKiii]

I was a little mixed about how much detail to include, because no one will read it if it's too long. But in this case, it was mostly selfish reasons. My thought is that at some point I won't remember what I did or why and it's a good place to keep it. Also I might I save a little time for the next guy.

Man that is me all the way. Its a place to store my thoughts and pictures to share with the community and reminders for myself when I forget 2 years from now. I do try to share knowledge or lessons learned for others too.

Only thing that has bit me is opinions and experiences change what you know today. Some of my thoughts from 2 years ago are not my current thoughts as I learn and grow. I'll see people quote my post from 2 years ago and I have to go back and clarify my new knowledge on the subject.

 

[rotauq]

Man that is me all the way. Its a place to store my thoughts and pictures to share with the community and reminders for myself when I forget 2 years from now. I do try to share knowledge or lessons learned for others too.

Only thing that has bit me is opinions and experiences change what you know today. Some of my thoughts from 2 years ago are not my current thoughts as I learn and grow. I'll see people quote my post from 2 years ago and I have to go back and clarify my new knowledge on the subject.

Even then, it's good to read back what you thought back then so you can reflect.

ps. not entirely related, but i just got myself a new soldering tool