It's finally done! :027:

I got the 4600 package in the other day and also got a pinion. I have it all hooked up now and I must say I am quite impressed! I haven't done any speed runs but I know it's fast and the torque is crazy. I had to adjust the torque curve to keep from spinning out on startup.

The Mamba Max ESC is tiny and is easy to mount. I had to shorten the motor wires 4" total to keep it neat and tidy. The USB interface and software couldn't be better IMO. Sure beats programming with the Tx only. Cogging is VERY minimal and only at extremely slow speeds under load (trying to go over something). I'd say it's equal or better than the Quark for cogging. The only problem I have is that the ESC gets to about 130 degrees, which is a little too hot for my liking especially since I haven't run it hard yet. I am using the built-in BEC so that makes a difference. To test how much of the heat the BEC causes, I ran the steering servo (85 oz-in Spektrum servo) back and forth continuously without running the main motor and the heatsink gets to about 90 degrees. So, I think I'll get a digital UBEC to keep the heat load off the ESC, especially since I'm thinking of going 3s.

I brought the Jato to work and played around for about 15 minutes, then brought it home and played around in my basement for another 30 minutes on a makeshift "track" consisting of various boxes and other obstacles. The thing literally turns on a dime. I then charged the e-moli 2s2p (6Ah) pack and only put 2.6Ah in it. That's less than half discharged for 3/4 hour of runtime. Not too bad. That equates to an average current draw of about 3.5A. Seems a bit low, but I was also running about 1/2 throttle tops in spurts. I'll be happy to get 40 minutes of parking-lot bashing time or 30 minutes race time, which I think is easily attainable.

The whole Jato is 2166g (4.78lbs), and 400g (~1lb) of that is the batteries. If I go with 2s1p setup, I can get the weight down to 4.3lbs. I'm using 54T/22T gearing for a total reduction of 9.64:1. The weight distribution keeps the front-end down to tame wheelies, so I'm not sure how it will do at jumping. I didn't design it for that, but I'm curious.

Overall, it's a blast to drive. It's lighter to carry around than the Revo, easier to charge, and smaller (easier to drive in smaller areas), so I can see myself playing with the Jato more than the Revo. I may take it to the track at my LHS (HobbyHaven) sometime before I wear the tires down to slicks. :)

An ESC temp of 130 isn't bad at all. At that point you shouldn't worry - the thermal protection doesn't even kick in until about 230 deg. My Mamba Max with 5700 motor regularly runs at 150-165 even with no air cooling on 2s Lipo, and the motor has gotten to about 160.

Wow, I guess I am OK then. I just don't like heat in my electronics - I get upset if my Athlon64 CPU gets above 113 degrees! I'll get a better feel for the real temps when I take it out and really put it through its paces at full speed. When I got the ESC I figured since the battery voltage at 2s wouldn't be high enough to cause the BEC to heat up too much. But that MM heatsink is sooo tiny! Makes my Quark look like a monster!

Even though my 2s2p emoli pack seems to hold up very well, I am a bit concerned about them. When I try to charge them at 6A (1C), I get a "voltage too high" alarm on my Hyperion 7i, even when hooked to the balancer. What I do to counteract this is charge at 6A until the voltage gets to ~8.3, then I lower it to 5A. This makes the voltage go down to ~8.0v. I again wait until the voltage reaches ~8.35 and then lower it to 4A, which reduces the voltage to 8.0v again. I keep doing this until I get down to 3A at which time it will charge properly without the alarm. During this, the LBA10 balancer LEDs flash for each cell at various times meaning the cell voltage is too high or each cell is out of balance. So, what I think happens is that the charger gets to 8.38-8.39v while the balancer is discharging and when the cells become OK, the reduced balancer discharge load causes the charger voltage to increase a little to the alarm stage. That's why my procedure, as tedious as it is, works. It is always right at the point where the charger switches from constant current to constant voltage mode. Is this common for people with emolis?

congrats on your finished project. I would love to see the Jato run at Hobby Haven sometime. If there is anyway to let me know when you might be over there that would be cool.

any finished pictues brian?? should be pritty quick!

Ozark

So that makes 3 of us here from Des Moines? You hang out at Haven?

Ozark: I usually throw the Jato in the car when I go to work "just in case", but I never know when I'll go. It depends on when I get out of work and the weather. HH is not exactly on my way home since I work right near the Target over by the Grimes exit and live on the east side, but I'll try (although today is rainy so it won't be today)...

Mike: Thanks for reminding me! I want to take some before I get it all banged and scratched up. I even got a new dig camera to take nice crisp pictures. :) I'll see if I can post a couple tonight...

mmmmmmmmmmmm crisp pictures:D:D

Finished product:

http://bgosselin.home.mchsi.com/e-jato/jato_done1.jpg

http://bgosselin.home.mchsi.com/e-jato/jato_done2.jpg

awesome dude!!! makes me want to convert a jato........

Thanks!

Brian... you work at H.T. by Target?

If it works out, stop by HH with the Jato next wednesday night. I'm usually there by about 6... races at 7:00.

Just ask where the guy with the BL 1/8 is.... :027:

I work near HobbyTown (about 1/2 mile away).

looks nice brian whats the next project!?

I don't know. I kinda like the Jato because it is easier to handle inside the house for rainy day "bashing". The Revo is great for outside where room is unlimited. I was thinking maybe an RC18, but it might be too small.

I was also thinking of making a "muscle car". It would be another 2WD vehicle meant for drag racing or pulling. Most of it would be custom built with maybe some parts from a current vehicle, like suspension. I figure a STRONG diff would be in order of course. I was toying with the idea of a planetary inline gearbox so the motor would be in front with a driveshaft directly to the rear like a real vehicle, but I don't know if those gearboxes could take the abuse (and they're expensive). That would leave plenty of room on the sides for batteries and would allow me to tune weight distribution by sliding them forward or backwards.

I ran the Jato around a parking lot today and it is quite fast, at least 35-40 mph. It handles VERY well. I had a blast. The rear tires are getting a little worn already, but I finally figured out how to control the throttle to prevent spinouts. I was able to run for about 35 minutes at high speeds, and that was after playing around with it inside work and demo-ing it at my nearby LHS (HobbyTown). SO, I'm happy with the runtime.

definatly, im looking forward to the next one! why wont you try a bigger scale like a baja roller?

Truthfully, bigger scale models are too expensive to build, especially when you are experimenting with stuff to find the right combination. Plus, they draw more current to get going, which is expensive in both cost and power. The larger models have too much mass IMO and break easier, unless of course you over-engineer the design, but then weight suffers.

i realise that brian, but you doing all these projects i though you would have the lage enough temptation to do something "DIFFERENT", if you know what i mean. i know it was just a suggestion.

I do want to try something different, but I'm not sure what. There are only so many ways to do conversions. Sure, there are differences in the way details are approached (like how I did my V1 BL Revo vs Dafni's), but you know what I mean. The Revo's were cool because of the challenges created by the room-hogging suspension. But now, it seems like almost everyone is doing a Revo. The Jato was cool because there weren't very many. I just don't know what to do now...

i think i found something that will be a harder challenge, try a team losi aftershock, has a thin chassis and a dual steering servos and oversized shocks for bashing draging and pulling! or try the lst 2

Aftershock? I would go for the Muggy. Thats gonna be my next one now that I think about it...

who makes the muggy?

Um, well, at $700 and $1,000, it will be a little while before I can even consider those projects. If I'm gonna spend that much, I might as well start on a totally custom 1/5 scale!

That Muggy does look interesting. Too bad there wasn't a kit without engine (and all related Nitro parts) and electronics. It would save the hassle of trying to sell those parts on the bay.

Yea....Thats the worse part. Mike, there made by Team Losi.

OK, I've worn off most of the tread on the rear tires and the ribbed edges on the front tires are peeling off, so I need new tires. However, I have RPM arms and the front wheels would need to be shimmed with 3 x #10 washers per axle to use 2.2" rims. Also, the hinge pin retainer (blue button head screw) needs to be replaced with 4mm set screws.

Before I finagle some 2.2" wheels/tires on there, are there any 2.8" wheel/tire combos that will work? Imex has some 2.8" tires, but only the dish wheels are in stock. Here is where I was looking (the tire I want is the center one in the top row). Is there anywhere else that I can get 2.8" tires/wheels, other than using Traxxas wheels?

Not that I'm aware of. I would go with the Anaconda's with the stock rims. They look killer IMO.

BrianG,
Traxxas 1972 and 1974 are a direct replacement using 2.2" tires.
They are what I used on my conversion Jato. I never changed any screws or had to add any spacers.
Those Traxxas rims are dyeable, too.

Yeah, they do look very nice. However, the stock Victory tires didn't last too long and am thinking the Anacondas won't be that much better. I'll probably just get the dish chrome, or the dish white and dye them black.

And you are running RPM arms?

have you googled it? you want the road runner? personally i like the "H" squares:) pl doesn't make em thats for sure

Yeah, I googled it and no one that carries Imex has any 2.8" stuff in stock. The road runners are ideal for me since I'm running strictly on-road (parking lots and such).

Well, just ordered the road runners and the white dishes. I also noticed that the 2.2" tires had a smaller diameter which means I'd have to gear up to 24T pinion to keep about the same speed. 22T 32p 1/8" bore pinion was hard enough to find!

they should have some grip on it then. but the stock jato tires are super grippy but wear out way to fast

brian, just to let you know, the anaconda tires are soooooooooooo sticky that on my nitro jato it is almost impossible to push sideways on glass and other smooth surfaces……………….

CG, how do they wear?

Yeah, that's how it usually goes. Sticky tires=fast wear.

not too much yet with the jato 2.5, about 5 tanks and not that much wear....................

Well, got the tires and rims in and they look nice. I dyed the rims black, but noticed it took longer than usual to dye dark enough. RPM stuff dyes VERY easily by comparison.

I took the Jato to a track at my LHS only to find out there was a big puddle on one end. Hmmph. I guess I should've called first. So, I ended up going to an out-of-the-way parking lot at the local fairgrounds. The tires work well at high speeds, but getting there is a challenge. Any more than VERY gradual throttle throws the Jato sideways. It takes me about 50-75 feet just to get to a speed where I can start laying into the throttle and even then I have to be careful. I've set all the settings on the ESC for as gradual power curve as possible.

Anyway, I was doing some high speed passes racing passing traffic which was on the other side of a fence when a cop shows up with his blues on. At that point I was wondering what the heck I did wrong - the grounds were open to the general public after all and I was way out of the way from any cars or people. So he walks up all serious and says "Sir, do you realize you were doing 47 in a 25?" and then cracks up. Whew! He apparently was watching for a while and got a kick from me racing the cars on the other side of the fence. So we starting talking a while about what was in the truck and so on. Finally, a cool cop. :)

Back to the tire performance: I had duct-taped the inside of the tires to prevent balooning, but by the end of the run, the tape had broken or come loose or something. Oh well. They still work well. In hindsight, I probably whould have gotten the soft compound for better grip, but I didn't want to be buying tires again next week. I might eventually pick up some anacondas for low speed, high power turns. Also, I got just under 45 minutes of mainly high-speed runtime with my 2s2p emoli packs and they were barely warm at the end.

For parking lot racing, I want to pick up some thin (~2" diameter) cloth/canvas tubes about 6 feet long that I can fill with sand to use as banks. That'll let me easily make any shape track I want while still being protable. They should be heavy enough to stay put. What do you think about this idea?

cool. sounds like you had a good day. that was really awesome about the cop.

That was actually yesterday, but I fell asleep while typing it up last night. When I finally tried to submit it, I got an error and didn't feel like typing it again right away. And yes, it was a good day. :)