Mojave Dove in, time to learn to swim

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findywen

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Location
Coachella Valley
Arrma RC's
  1. Mojave
Picked up a Mojave recently to begin my spiral into this hobby. I had been looking at bashers recently as something fun to do with my son (15) and after watching a lot of youtube, I happened to be near an RC store (Ultimate Hobbies in Tustin Ca) and pulled the trigger, as half impulse, half pre-meditated decision.

I have had it out a few times, and am really having fun with it, today I might even let my son use it. With that though, I come here seeking advice. I live in the deserts of southern California, so I am running almost entirely on loose sand, fine as well as coarse. I am interested to hear what others are running as far as oil weights for diffs and shocks in this terrain type. Generally I am looking at improvements in handling on the soft stuff, that being said I know there is only so much control when the ground moves under you, and I am still learning control myself.
 
Welcome to the forum!! There are a lot of great people on here to help answer questions and give their knowledge and input. I would suggest using the search bar before starting a new post as usually the question you have has been covered many times in previous posts. I don't have a Mojave personally I have the K6s and I run on kinda similar sandy dirt. A lot of us run 20-30k in rear diff and 40-70k in front and I'd go to 500k+ in center so you get more control for turning and less ballooning in front tires. Suspension is more so to your liking and you can adjust that by preload on springs or also changing shock oil to heavier or lighter again depending on your preference.
 
Welcome aboard! I'm running my Mojave in fine powder over hard pan. I'm still running mine with stock fluids. I may be wrong, but in my circumstance, I don't think I would notice enough difference to change them.....I guess if you've seen me drive you would understand :LOL:
 
Welcome!. Get used to maintenance on your wheel bearings running in fine sand. I'd check after every run for binding but they would probably need cleaning every 10 packs. Get a spare set of bearings, they are fairly cheap and easy enough to replace and it minimizes downtime.
Jims bearings or FastEddy type are ok.
 
Well, gave my son a chance to rip it up in one of the washes out here. About 5 minutes in he said "oh now I see why you wanted one of these."

I tried to get some video, but that is about the time it decided to cut power. Seems like we overheated, the ESC and Motor were both showing 160+ degrees when I checked it. Which surprised me, since we were only out there for about 15-20 minutes, running on the stock 16t pinion and most of the time not running full out. I am about to prop it on the table and see if maybe we got some debris in the ESC fan, and maybe run it a little while to see if the fan is coming on at all. Will actually be pulling apart the wheels / bearings as well, as jkflow mentioned, as the front right wheel had stopped rotating at one point. I manually rotated it a bit which seemed to unbind things, and it started working under its own power, so if something was causing undue friction in the drive I could understand why the motor was running hot.

I think one of my first upgrades will be investing in some underbody guards to keep some of this sand and grit out.
 
Add a fan to your motor (dual yeah racing type). What are your ambient temps?
ESC has thermal shutdown and will survive, motor will not.
Very common to shut down under heavy load (sand) and having fun. Sand is a killer and taxing on the system but many people do it. As soon as you notice something wrong stop and check, binding is bad on any day.
 
Ambient temps yesterday were probably in the low 60's
It didn't occur to me that sand would be considered a heavy load, but thinking about it that makes sense, going to have a lot more spin without going anywhere fast. And the wash has a lot more soft sand than where I was running the other day.
Yeah a heat sink and fan setup for the motor was on my short list of upgrades, we only get 3 to 4 months of nice temperatures out here, most of the year its 90 degrees +, not leaving a whole lot of delta between ambient and running hot for the RC.

That actually brings up a question, I have seen a chart that tells what using thicker and thinner diff oil does in each of the 3 diffs in regards to acceleration and steering. But how does that effect motor heat? A thicker oil applies more even power between the two end points (as I understand it). How does that effect work/heat from the motor, or is there no noticeable difference without going to extremes like 1mil weight for center diff.
 
Thicker fluids ensures that the power is distributed evenly. You do not have all the power going to one wheel in case of a lift and end up in a blowout. That implies that more power ends up on the ground and it will generate more heat. Never did a real life comparison though and I'd think it's minimal.
Same weather and season here, bigger fans will help but do some research, there are cheap options if you can solder.
 
can confirm, the ESC fan failed. Ran it a bit this evening, 65 degree ambient temp. ESC hit 160, and motor was still at 130-140 range. And even more telling, the fan itself wasn't running. There was some small stones in the heatsink for the ESC, so it is entirely possible some debris caused the fan to seize.

So, new fan for the ESC, heatsink and fans for the motor, some inner fenders from Scorched Parts, and a complete set of bearings. I'll pickup fluids from a local RC shop and plan to have some fun the week of thanksgiving doing a few upgrades.
 
Replaced the fan, and took it out with my son this afternoon.


And of course, got a few sticks and fibrous bits into it and jammed the ESC fan again.

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Luckily when i got home the scorch parts inner fenders were delivered, so I will be putting those on before the next run. Also after removing the debris and tapping it a few times I was able to get the ESC fan to come back to life. I think I am going to keep a few extra 35mm fans laying around though just to be safe.
 
Those inner fenders are a game changer, for the terrain I am in. Had it out this morning for a good half hour of continuous bash in the desert and the interior is practically clean. Never had the ESC shut down due to fan getting clogged. Checked temps afterward and with ambient temp in the 80's I showed about 150 on the ESC, 145 on the motor, and 125 on the batteries. I did have to doctor the body mounts a little to get the body clips to fit, but otherwise had a good clean install. If/when I decide to expand my garage Inner Fenders are going to be my first upgrade I think, assuming wheels are under the body.
 
I have the inner fenders also. A must have or she collects tons of debris. Your temps are up there because of your hot ambients. And the chassis is closed off from the inner fenders. Cool Air exchange becomes limited. Just Normal with these fenders.
Get "good" fans, double fans on the motor, a better High Speed ESC fan if you didn't have already. Your temps are actually borderline too hot. Luckily, you didn't cross the Thermal Cut threshold but you were about to IMHO.:cool:

Edit: the body holes in the body do have to be modded ( opened up a bit) to fit with these fenders. And also opening up the body "pin" holes makes a huge difference. Or Its just a bear to mount the body. I know.
 
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I went a different route for keeping debri out of the chassis . Also put on heat sink / fan combo to because now with cover temps will go up .

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