LST diff in a revo...

[lincpimp]

Ok, so a few people asked me to look into this. A very nice man (JThiessen) sent me a piar of revo bulkheads to experiment on. Here is the result:









Needs a slight amount more work to get the bulks to touch without a little bit of flexxing. This is definately the cheapest way to get good diffs in a revo. Expect my 1521 powered revo to have lst diffs...

For anyone who is not familiar with lst diffs, they are 1/8 scale 6 spider design diffs. You can get a variety of different ratios for the ring and pinion, and a variety of different materials for those gears. Losi make a nice heavy duty plastic cup with steel inserts for the cross shafts. That cup is lighter than an all al cup and has plenty of strength. The also have tin coated ring and pinion gears in 13/43 ratio (stock lst ratio). 8b and 8t gear sets will fit the cups too. Big bearings for the pinion, which has an 8mm shaft. I may detail the varieties of lst diffs in another thread, for those interested. These are stout diffs, and cheap on ebay, usually 20 bucks for the diff in the case. There are a few different trucks that use these so parts are easy to find.

[gtxracer]

Wow....great tech info linc! I never had problems on 4s in my two E-Revos, but I could see how a 1521 and high voltage could make some diffs explode. Way to go!

[lincpimp]

Originally Posted by gtxracer

Wow....great tech info linc! I never had problems on 4s in my two E-Revos, but I could see how a 1521 and high voltage could make some diffs explode. Way to go!

Thanks, I will get a diff built for the case and see how well the center driveshafts line up. The stock lst diff outputs should fit most cvds. The input will require a 8mm id cvd cup, or mike's adapter to use the stock sliders. I have those adapters so I will give them a try. I will test with a stock revo chassis and an erevo chassis.

[_paralyzed_]

noob: is there anything Linc won't put an LST diff in?

me: hide your girlfriend

[Semi Pro]

nice job, looks like they are going to work out nicely

[JThiessen]

Looking good Linc. Looks like you should be able to just clamp the two bulks together and run a drill into the input shaft hole to open it up. Could you mic that input casing on the LST?

[lincpimp]

Originally Posted by _paralyzed_

noob: is there anything Linc won't put an LST diff in?

me: hide your girlfriend

Linc: what? no lst diffs in bed? What kind of rule is that

Originally Posted by Semi Pro

nice job, looks like they are going to work out nicely

I think so. My only question is clearance for the center driveshafts. I know cvds will fit fine, but I am not 100% on sliders yet.

Originally Posted by JThiessen

Looking good Linc. Looks like you should be able to just clamp the two bulks together and run a drill into the input shaft hole to open it up. Could you mic that input casing on the LST?

Thanks. Not sure if I have a large enough drill to do that, plus addl material needs to be removed in key areas to allow the cases to fit. Bit of trial and error involved. I will assemble the diff and put the lower skid on the bulks. I want a tight fit, but do not want to distort either the bulkheads or the diff case.

[Semi Pro]

could you post some pics of the inside of the bulkheads

[jayjay283]

you used that heavy duty lst diff thing ? does it work as cool as it looks, i still havent opened the others lol

[lincpimp]

Originally Posted by Semi Pro

could you post some pics of the inside of the bulkheads

Let me get them finished and I will take a few snaps. Depending on what I can get figured out, I may make up a few sets, if anyone is interested...

It is not a difficult mod to do with the right tools, but there is not a ton of material to work with, and specific areas are very hard to get right.

Originally Posted by jayjay283

you used that heavy duty lst diff thing ? does it work as cool as it looks, i still havent opened the others lol

I had a good look at it, and it seems just like the hpi version, which never wears out. It is definately a big improvement over the stock plastic cup. These are not really needed for a r/c with light, small tires. But a MT with big tires and thick diff fluid puts alot of strain on the cross shafts, so having the steel inserts will spread the load and cut down on wear at the same time. Plus it is lighter than the nova rc diff cups, and light is good IMO.

Was thinking about doing the exact same mod, but don't have any spares lying around and I don't feel like taking my e-revo or muggy apart right now. I do have a revo and muggy diff case and measured the dimensions of both. Differences in lenght, width or height is no more than 2mm.

Revo outer diff case width / length / height: 35mm / 54mm / 43.3mm
Muggy outer diff case width/ length / height: 37mm / 55.5mm / 43mm

So, subscribed to this thread to see your progress. For it to be a cheap mod it would require to keep the stock front, rear and center driveshafts. Centers are probably covered with Mike's couplers. But how about front and rear driveshafts?

[BL_RV0]

Looking good. Hope to see more progress.
Off-topic: how is the rotor wrapping going?

[blueb8llz]

hey linc. what ever happened to the lst diffs for the 3905? were you ever able to get those to fit? werent you gonna make them for sale? if so, id be very interested.

[lincpimp]

Originally Posted by drkdgglr

Was thinking about doing the exact same mod, but don't have any spares lying around and I don't feel like taking my e-revo or muggy apart right now. I do have a revo and muggy diff case and measured the dimensions of both. Differences in lenght, width or height is no more than 2mm.

Revo outer diff case width / length / height: 35mm / 54mm / 43.3mm
Muggy outer diff case width/ length / height: 37mm / 55.5mm / 43mm

So, subscribed to this thread to see your progress. For it to be a cheap mod it would require to keep the stock front, rear and center driveshafts. Centers are probably covered with Mike's couplers. But how about front and rear driveshafts?

Font and rear diff to wheel driveshafts are easy. Just mod the stub axles from the revo (cut off the threaded portion) and replace the lst output cups with them. Also the case size is not realy the reason it takes alot of modding to fit.

Originally Posted by BL_RV0

Looking good. Hope to see more progress.
Off-topic: how is the rotor wrapping going?

Thanks, I have put the rotor wrapping on hold as I needed to clean up my workbench, and that required building a new charge station, moving my grinder, drill press and band saw. Plus I had to finish up the 6x6 maxx and fix a few lipos. So I will get back to that this weekend if time allows.

Originally Posted by blueb8llz

hey linc. what ever happened to the lst diffs for the 3905? were you ever able to get those to fit? werent you gonna make them for sale? if so, id be very interested.

I have about 3 hrs on the lst diffs in the maxx and it is working well. I really need to have the front case support machined from scratch, as all of the other existing case supports are too thin to mod to the correct id and do not really have enough material to accept the cuts I need to make. I may weld some steel ones up, as that would offer the strength I need without being extra difficult to machine.

[BL_RV0]

Ok. Hope to see more progress soon in both areas.