Losi Baja Rey 1/10th 4WD RTR desert truck

[fyrstormer]

A few changes to mine:

1) I replaced the stock receiver with a non-AVC receiver and a standalone gyro. The truck is noticeably more powerful without the AVC stifling the throttle input every time I steer. Somewhat ironically, this also makes the truck less likely to traction-roll, because I can more easily force the rear end to slide-out when cornering. Also, the Futaba gyro doesn't do strange things like intermittently deciding to ignore my steering inputs like the AVC did.

2) I weighed the spare tire -- 114g -- then opened the "fuel tank" and added a comparable amount of weight in the bottom of the tank. Then I re-mounted the spare tire. The rear suspension is more responsive with the extra weight, and adding the weight to the bottom of the "fuel tank" box also lowers the rear end's center-of-gravity a little. Both are good things.

3) I added a little more preload to the front shocks to discourage the front wheels from tucking-in and causing traction-rolls. It was a minor improvement, but an improvement nonetheless. I left the rear preload the same despite adding extra weight; I don't need to worry about the truck dragging its butt in the grass, because there is no butt for it to drag -- the back half of the vehicle is open space with a solid axle that's always the same height off the ground no matter what.

Overall, the trick with these hybrid-suspension vehicles is to get more sprung-weight as low as possible in the rear, and to keep the overall center of gravity as low as possible too. The Baja Rey is definitely off to a good start in that respect; I will continue tweaking it to see if I can improve it more. It would be nice if there were room to mount the ESC lower, but the battery tray, motor, and servo occupy all the available space on the chassis plate. I briefly entertained the idea of mounting the ESC in the "fuel tank" box, so the weight back there would be useful instead of dead-weight, but then I decided I don't want the ESC in such a vulnerable position. I may be overestimating the danger, though.

I wish the gears were quieter. I feel bad about test-running it in the middle of the night.

I took mine out for another drive today, once again mostly on pavement because that's what parking lots are made of. I'm getting the standalone gyro dialed-in, and getting the left/right steering travel set so the truck turns the same radius in both directions. It definitely likes having the extra weight in the bottom of the "fuel tank" box.

I'm starting to figure out how to drive it well; you don't want a lot of steering angle, you want just enough for wide-to-moderate turns, and then you make sharp turns by throttling-up to induce oversteer. That keeps the outside-front tire from tucking-in and flipping the truck.

The center diff definitely needs thicker oil than I started out with. 10K was good at first but it's not enough now that I've disabled punch-control on the ESC and removed the AVC radio.

Also, I installed some mudflaps from the TEN-SCTE today, because why not:

[LGrocks]

Excellent info Fyrstormer. Can the AVC system be shut down? Does it affect performance at all when its "off"?

[fyrstormer]

I tried to shut it off, following the instructions about rebinding with a plug in the Bind port and another plug in the Disable port, and it just wouldn't stick. No idea why. I just pulled the receiver entirely. I'll probably never have any use for the receiver, because the firmware on my DX4S is too old to know what AVC is. In order to update it I'd have to get the latest firmware which would delete compatibility with old DSM1 receivers, and I have about 20 of those in service so my choice is clear.

However, if you have a DX4* controller that does know what AVC is, you can adjust throttle control and steering control separately, select how much the steering input overrides the throttle input, and soft-disable the AVC using controller settings. I was trying to hard-disable it, which normally is only used for race events.

[fyrstormer]

By the way, does anyone know what the shock oil weights are in this truck? The suspension is set up just about perfect for me, so I'd like to be able to rebuild it the same as stock. I talked to a rep at Horizon and he didn't have that information.

[fyrstormer]

Replaced the stock electronics. Kept the motor though, it will do fine until I can get a 1/8"-to-5mm adapter for the pinion gear to use my preferred motor.



The ESC is now mounted lower. (the old ESC is set in-place for comparison's sake.) Probably doesn't affect the center of gravity that much, but it makes me feel good:

[fyrstormer]

The truck steers much more precisely with the Hitec HS-7955TG servo and the TLR aluminum servo horn I installed, and the SkyRC ESC has typically excellent motor startup, with none of the cogging that the Hobbywing ESC exhibited. The HS-7955TG servo is much faster than the stock servo, so the gyro can correct the truck's steering without making it wiggle like an old Cadillac with blown-out shocks.

I didn't have any 20K oil and I was too lazy to mix some up, so I put in 30K oil instead. Based on what I saw when I opened the center diff, the 30K oil should shear down to 20K pretty quickly anyways. So, 30K oil is good for popping wheelies on dry concrete, if there's anyone looking for that kind of action. I left the front diff completely open because it still handles corners better that way; just thickening the oil in the center diff improved acceleration off-road quite a bit.

I noticed a longer runtime with the new setup. Not sure if it's because I'm not using the cheap Hobbywing ESC anymore, or if the 30K oil in the center diff is keeping the truck from wasting power; probably some of both.

I'm learning that when the truck traction-rolls in a corner, the best thing to do is keep the steering turned and stay on the throttle; the truck will usually roll far enough that the wheels touch the ground again, and then they can grab and pull the truck upright again. But if you let off the throttle and straighten the steering, and then try to use the truck's own power to flip it upright after the fact, it almost never works.

In any event, I'm still really happy with this truck.

[CM9000]

the center diff stock.. its not filled well. causing the front tires to spin faster off road.

I went to the sandpit rc race facility this past weekend on Saturday for a points race but nobody showed. so I had more than enough time to beat the hell out of it in blown out farm dirt race track outside. and then of course the oval.

after I found one more weakness... the front bumper

I broke it or somebody else did driving it. idk.

the truck jumps awesome without the spare tire.

I think it needs a pro4 and a gen 2 rx8 esc...

I ran holeshots on the indoor track and traction rolled only on the bank once.

it goes through woops with ease.

stiffer front sway bar, and longer ends on rear for adjustability is in need.

I think 20k or 30k will be good as well for center. I might do 10 in front after I get my truck back from mscs.

[fyrstormer]

I got an email back from Horizon. The front and rear shocks both use 30wt oil. On my Yeti I had to use 45wt in the front and 10wt in the rear, and the suspension still didn't work the way I wanted it to. Amazing what a difference a properly designed chassis can make.

I still think the front diff works best when lightly greased instead of filled with any kind of silicone oil. Really light silicone oil like shock oil might work, but it wouldn't provide enough lubrication for the internal gears. According to industrial manufacturers of silicone lubricants, silicone is not suitable for metal-on-metal lubrication, but we use it inside diffs anyway because the limited-slip effect is a worthwhile tradeoff for shortened gear lifespan. But as open as the front diff needs to be (in my opinion, of course), it's better to use grease instead. The truck doesn't really need any limited-slip action in the front diff anyway, because the locked rear axle can move the truck forward just fine by itself, as long as the center diff is stiff enough to actually transfer a useful amount of torque to the rear axle.

Opening the front diff helps to reduce the need for a stiffer front swaybar. Also, adding a little preload to the front shocks helps too. Its fine to let this truck lean backwards when driving, because there's no chassis plate in the back to drag on the ground.

[ser3100]

I like both of your points! Ill keep them in mind next time im out. Havent really driven them as of late. Been too hot and too busy with other things.

[CM9000]

mine looks beat to hell right now and needs a good cleaning. I don't think anything else can break on mine..

and a touch on shock oil in the front diff...

I use 50wt shock oil in my gear diff on my 22sct 2.0 "kit" truck. the truck rocks! so I don't think it would actually be a problem if we did the same for the front diff in the rey.

[wrightcs77]

So mad.....ordered from horizon hobby. Tracked it thru fed ex and I knew it required a signature, so was expecting to get home, grab the tag, go to the fed ex shop, sign for it and take it home. That apparently is not an option? HH sent it and required I be home to get it, I can't go pick it up at the fed ex local center? I work 150 miles away from home, not sure what the hell to do now......................

[LGrocks]

Originally Posted by wrightcs77

So mad.....ordered from horizon hobby. Tracked it thru fed ex and I knew it required a signature, so was expecting to get home, grab the tag, go to the fed ex shop, sign for it and take it home. That apparently is not an option? HH sent it and required I be home to get it, I can't go pick it up at the fed ex local center? I work 150 miles away from home, not sure what the hell to do now......................

Is it FedEx? If so, did he leave a door tag?
I was pissed too. Mine was supposed to be here today too. Signature reqd', nobody home, so FedEx guy left a tag that I can sign and put back on the door. So he can leave it tomorrow. Maybe you can sign the tag?

[wrightcs77]

Originally Posted by LGrocks

Is it FedEx? If so, did he leave a door tag?
I was pissed too. Mine was supposed to be here today too. Signature reqd', nobody home, so FedEx guy left a tag that I can sign and put back on the door. So he can leave it tomorrow. Maybe you can sign the tag?

FedEx.....tag said had to be home, can't sign tag and leave it, can't pick it up at the fedex office.......can't do crap.

[Rjohn929]

Call them and tell them what's going on. There has to be something they can do. Worst case, they send it back to horizon who will have to send it again. Not the end of the world but kinda expected if it was sent signature required.


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[fyrstormer]

Do you have someone who can pick it up for you? You should be able to send an "authorized agent" to pick up the package for you as long as you sign the slip.

Also, holy crap, get a job closer to home or move closer to your job. A 300-mile daily commute is insane. No amount of money is worth that much driving.

[Arctic Cat ZRT]

The hole signature crap is why I don't order from direct from horizon anymore. At least with most other sellers I can opt out the signature requirement at my own risk. Also UPS lets you sign electronically if you sign up for My Choice.

I've heard of similar situations in which you call FEDEX and they will hold it at their local terminal for you to come pick it up there. You could also try and send it to your work if they don't frown upon it.

[TTDRIVER13]

Hey guys new to the site, you guys have the most active baja Rey thread I can find and I am a baja Rey owner as of today so I joined to share my experiences and learn what I can witch I have read this whole thread and gained a lot already. Absolutely love the truck, only have driven it for like 10 min and now it's in 1000 pieces.. I could not stand the movement in the steering so I spent some time tonight tinkering with it and have found a band aid fix but we will need a more permanent one moving forward and hope losi steps up after I contact them tomorrow.
Here's a couple pictures.

[fyrstormer]

Nice cutout job on the windows, but my motor doesn't get hot enough that it's painful to touch, so unless you're really bogging-down your Baja Rey, the extra airflow won't do much.

There's also a thread on RCTech, and a few individual-member threads on URC. Probably the same few people participating in all of them, though.

[ser3100]

Quick question for you guys. Whats the effect on the car if i swap the pinion gear to the optional 10t that comes with the truck? Im using the one that came with it as box stock. Im also running 3s. Thanks!

[Rjohn929]

I run the 10t on 3s. I don't need it to be uncontrollable fast and I have a few 3s floating around. I prefer not to bash with my 2s race packs.

What steering issue are you talking about? I changed my servo and drag link the day I bought it. It feels pretty good to me now.


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