On-road BL project - Page 2 - RC-Monster Forums

MetalMan · 07.05.2006, 09:38 AM

How about a Mamba Max? It should work very well. Based on what Batfish used, the Mamba Max with the 4600 motor should work excellently.

Batfish · 07.05.2006, 09:54 AM

One other note for you with the Jato - the Mod .8 spur gear that Traxxas uses on the Jato meshes up with standard 32 pitch pinions just fine. I ran regular Robinson 32 pitch pinions on a 48T Mod .8 Jato spur for 3 months with no noticeable wear.
If you wanted to go to Mod 1, the Revo spurs bolt right on to the Jato slipper assembly. It reduces your gearing options overall, but does give you the ability to easily use Mod 1 if you want.

Yet another Mod 1 option is the Associated MGT spur gears. The slipper peg holes line up with the 3 slipper screws for the Jato. This spur will stick out a little further than the stock spurs, so make sure your motor shaft is long enough and the pinion will reach. This option does require two modifications, though. First, the center hole has to be shaved out a tiny bit (maybe 1mm - I did it with my dremel and a sanding wheel) to accomodate the bearing it rides on. Second, one of the screws that hold the rock guard comes up right under the spur gear and will interfere with any gear larger than the stock Jato 48T. If you remove/relocate that screw and cut off the plastic nub, you can use a larger spur.

MetalMan · 07.05.2006, 10:22 AM

I used a MGT spur gear on a Revo slipper clutch unit for quite a while. If you have a 5mm drill bit, you can bore out 3 of the wholes (triangle pattern) on the slipper clutch plate and the spur gear is a nice tight fit - that doesn't stick out far.

BrianG · 07.05.2006, 01:49 PM

Thanks guys. I have a place to start.

Batfish: Yeah, I figured the Jato used 32p teeth from parts in the stores. Not sure yet if I want to stick with that or go Mod1. I guess I'll have to pick up a Jato roller and go from there. I plan on coverting to single speed and use motor brake, so tranny work will be in order. While I'm at it, I'dd do any kind of drivetrain mods I can. To get better runtimes (and less current draw),, I was thinking of a slower motor, using 4s E-Molis and gearing it up, something like a XLBasic 2400?

MetalMan; The Mamba Max package does look like it would work, and relatively cheap too. Seeing the picture, those motors look to be an "S" can, is that right? With a kv of 4600, that's a 6 or 7 turn right? That's gonna suck quite a bit of current too I'm assuming. If I decide to do low cell counts, that will work fine. I'd like a bit more runtime though...

Sorry for all the newb-like questions. I've done two Revo conversions and both are relatively heavy trucks, have quite decent drivetrains, and have room for basically any reasonable amount of cells. The Jato is lighter and only 2wd, so probably has a not-so-robust drivetrain. So, I don't want to throw too much power into it and wreck everthing - then again, I DO want insane speeds (~50mph for me is insane) :)

Batfish · 07.05.2006, 02:10 PM

Quote:

Originally Posted by BrianG

The Jato is lighter and only 2wd, so probably has a not-so-robust drivetrain. So, I don't want to throw too much power into it and wreck everthing - then again, I DO want insane speeds (~50mph for me is insane) :)

Stock 2-speed with a xl4200 and 3s lipo is right around 50mph with a 21t 32p pinion. I can say that the Jato's drivetrain is pretty strong and not at all loose, but it is all plastic gears so you can only put so much torque through it before they start stripping.
It's also nice that the rear axle diff is a geared diff instead of a ball diff. Ball diffs have a harder time coping with large amounts of torque.

squeeforever · 07.05.2006, 02:00 PM

I would go for a 1920 if you can. That would be the ultimate motor for a small light weight truck.

Brian, was that your E-Revo on ebay?

MetalMan · 07.05.2006, 02:35 PM

Just to add this, the XL4200 and the MM 4600 motors should draw about the same current, the 4600 a slight bit more.
If you go by Feigao's turns, the 4600 could be like the loaded kv of a 7s.

The only way to get longer runtimes is to get batteries with higher capacity (Lipo) or go with higher voltage. For higher voltage, extra NiMh cells would add extra unnecessary weight - Lipo's the option for high voltage as well. For 6 NiMh cells, you're going to have a bit of a hard time coming by a motor that's powerful enough yet light enough at the same time - a Feigao 380C 6L would probably be the best choice for 380 motors (and that has a similar kv to the MM 4600 motor).

BrianG · 07.05.2006, 03:47 PM

Squee: Yeah, that's my E-Revo (v1) on Ebay. I like V2 much better so I'm keeping that one. Just curious, what is a good and fair price for something like that? The proceeds from this sale will be going to the purchase of a good Lithium charger and batteries for V2 Revo.

Batfish: I'm glad the tranny and diff is strong. Like the title says, it will be for on-road use only, so it won't be subjected to the same rigors as a normal MT or buggy. Once I get the roller and get a feel for its structural strength/weight/etc, I'll have a better idea if I want to go with 3s or 4s and then an appropriate motor. I know enough of BL to know the relationship be and power. I'm leaning to a slower turning motor at higher voltage, but that depends on the physical space on the truck and the weight.

MetalMan: Feigao's chart is what I'm using to get a rough idea of the kv vs turns ratio and therefore, current draw. I'm hoping that by using higher voltage and less vehicle weight, I can keep current draw to ~80A peaks with ~20A (or less) average current draw. I figure the E-Molis might be a good pick for this. I know and realize that e-molis drop voltage after 30A or so, and I'm actually counting on this a little to help keep the "punch" down a little on take-off to protect the drivetrain.

Thanks for the assistance! Once I get going with this project, I'll post back with my progress and pics...

Batfish · 09:24 PM

Quote:

Originally Posted by BrianG

Batfish: I'm glad the tranny and diff is strong. Like the title says, it will be for on-road use only, so it won't be subjected to the same rigors as a normal MT or buggy. Once I get the roller and get a feel for its structural strength/weight/etc, I'll have a better idea if I want to go with 3s or 4s and then an appropriate motor. I know enough of BL to know the relationship be and power. I'm leaning to a slower turning motor at higher voltage, but that depends on the physical space on the truck and the weight.

Just keep in mind that on-road applications typically have much more traction than off-road. This extra traction can actually be more harmful to a drivetrain than slipping in the dirt off-road.

BrianG · 07.05.2006, 10:28 PM

Quote:

Originally Posted by Batfish

Just keep in mind that on-road applications typically have much more traction than off-road. This extra traction can actually be more harmful to a drivetrain than slipping in the dirt off-road.

Good point.