LST diff in a revo...
 

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:

http://i206.photobucket.com/albums/b...p/DSCF2796.jpg

http://i206.photobucket.com/albums/b...p/DSCF2795.jpg

http://i206.photobucket.com/albums/b...p/DSCF2794.jpg

http://i206.photobucket.com/albums/b...p/DSCF2793.jpg

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.

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! :mdr:

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.

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

me: hide your girlfriend

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

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?

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

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.

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.

could you post some pics of the inside of the bulkheads

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

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.

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?

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

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.

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.

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.

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.

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

thats cool, im planning on doing the same thing and i would love to see how you did it before i start doing mine

I just purchased two LST2 diffs, aluminum case, for a total of 56.00 (shipping included).
I would like to know which different gear ratios will fit that housing. If anybody has a list out there for me that would be great.

linc, any update on this mod? Thanks.

Following Linc's lead on this, I ordered a couple LST2 diffs on ebay. Total cost was $52 shipped to me in Canada. Here are the updated pics of the rear bulkheads. Sorry for changing this post, the old links would not have worked anymore anyway.

http://i177.photobucket.com/albums/w...LST2_diff2.jpg

http://i177.photobucket.com/albums/w...LST2_diff3.jpg

http://i177.photobucket.com/albums/w...LST2_diff4.jpg

http://i177.photobucket.com/albums/w...LST2_diff5.jpg

http://i177.photobucket.com/albums/w...LST2_diff6.jpg

That is alot of material removed... I used a plastic muggy case to do the one I did... I will have to compare the plastic cases to an al case...

I also modded the rear bulk first to fit the LST2 aluminum case. I broke out in some spots, not to worried about the bulkhead breaking yet. I'll be running steel center shafts with Traxxas steel CVD's. I hope they work because I ordered two more for one of my other revo's.

mistercrash I just checked your photos of the lst in the revo bulks, I didn't take that much material out of the side walls on mine, they are thin near the pinion, but the area buy the ring gears is still mostly there. I also ground the rear boss of the lst diffs as much as I dared to reduce the amount of clearance on the rear of the bulk. I will try to get some pics up later.

Well looking at my first attempt after I came back from work tonight, it was now obvious that I screwed it up. I removed way too much material. My only excuse is that I was in a hurry. I redid the whole thing with another set of bulkheads I had and it looks much better. I will post pics tomorrow morning. One thing is for sure about this mod, I hope not to break a bulkhead after :oh: It's a pain to make another set.

I changed the pics in my post #19. They now show the second set of rear bulkheads I did yesterday night. They're much better. I'm now waiting on Traxxas stub axles to use as out drives on either side of the diffs and two 8mm bore Steel Revo drive shaft coupler from RC Monster for the center shafts. I have to rebuild the diffs, one is very notchy and I'm sure it's because it's not shimmed right. Anyone running these diffs can recommend what weight lube to put front and back?

Thanks.

To who ever is interested. I did the front LST2 diff intall. It's done, both front and rear bulkheads are ready to try out on the BL ERevo when it comes in. Only time will tell if the bulkheads hold up after removing so much material from them. I know some of you are using LST diffs already and you had no issues yet so I'm confident it will be ok. Here's a few pics of what I did to the diff cases, the stub axles and the completed front installation.

http://i177.photobucket.com/albums/w...LST2_diff1.jpg

http://i177.photobucket.com/albums/w...T2_diff2-1.jpg

http://i177.photobucket.com/albums/w...T2_diff4-1.jpg

http://i177.photobucket.com/albums/w...T2_diff5-1.jpg

http://i177.photobucket.com/albums/w...T2_diff3-1.jpg

http://i177.photobucket.com/albums/w...iff_front1.jpg

http://i177.photobucket.com/albums/w...iff_front2.jpg

http://i177.photobucket.com/albums/w...iff_front3.jpg

http://i177.photobucket.com/albums/w...iff_front4.jpg

Looks good MC. I should be doing this soon for my latest erevo build. Since I sold all of mr revo diffs I am stuck with the lst diffs! I have had zero problems running the lst diffs in the lst, which is a larger, heavier truck with bigger wheels/tires.

Thanks and good to know the LST diffs are strong.

I just finished my front bulks last night. I hope to be punishing mine soon. I plan on running a neu 1515 1.5d on 6s (yes thats 59,000 rpm's). Need the rpms since the lst2 has such a slow gear ratio. Might have it running this weekend.

No, you don't need more RPMs, you need to simply gear up. I wouldn't run more than 5S on that motor. Most likely 4S.

Oh come on, dont be scared. Wouldn't you like to know just how good a Neu motor really is? Has anyone heard of a Neu exploding do to RPM's? They are rated to 60,000 its not like a gas motor were high rpm tends to try and pull things apart. I do realize I can gear up, but I really want to see how long it will run on 6s.

Hopefully your bearings will stay intact :rofl::rofl:.

I feel like an idiot, I never stopped to think about the LST's diff ratio compared to the ERevo's diff ratio. I don't even know what both ratios are. Is there a big difference between the two? What spur and pinion would be good to run with LST diffs?

LST-43/13
Revo-37/13

the LST uses the same ratio as the hybrid diffs that Mike sells for buggys, and playing with your spur/pinion ratios will offset the diff ratios

Thanks for the info, I appreciate it. Now I feel a little less like an idiot. :lol:

I ran my 1.5D on 5s and it handled it just fine, but it didn't hit full throttle for much more than 1-2 seconds before it ran itself out of room. On 4s that motor (despite the 30k fluid in my CD) would put my Muggy back on it's wing with the front tires ballooned waaay out (40 series look spectacular when they're ballooned that hard :lol:) and on 5s I was able to backflip it over the wing. Max motor temp I ever managed to get out of it on 5s was 150 degrees, but it thermalled my MGM 16018 (160-180).

Ok so i have the Diffs mocked up in an extra set of bulkheads, but im wondering what i can do for a driveshaft to fit the LST diff and get on to the traxxas gearbox? Any suggestions. I toyed with using a set of driveshafts for a ofna buggy but im not sure if they are long enough. What is everyone using/planning on using?

I plan to use stock erevo sliders, and these to attache the sliders to the 8mm pinion of the lst diff.

Not sure if I will use the stock wheel driveshafts or not...

For center driveshafts I will be using Kershaw Design steel drive shafts. I have RC_monsters 8mm drive cups on the LST diffs and traxxas cups on the erevo tranny.
I'm also running traxxas cvd's at all 4 corners. I have respect for the guys that can keep the plastic stuff alive. I couldn't, trigger finger must be to heavy I guess. I will be trying traxxas new summit axle shafts very soon behind a Neu 1515 1y on 4s. I hope they work, becasue that revo is set up with the long travel rockers and adjustable wheelbase set all the way back. Not a rock crawler but I wanted that truck up in the air.

Oh dear! What have I done :whistle:

I was worried that with the material taken off the inside of the bulkheads, they would become too fragile so I did the best I could to reconstruct on the outside with melted Nylon Composite from a scrap bulkhead. I believe those rear bulkheads are now very strong but it looks absolutely awful. :lol:

fugly bulkheads


I need a plastic welder really bad.

Looks good:whistle:

You have the right idea though! Urethane Supply Company make some really good plastic welders, and their uni-rod is similar in material to the bulks, so it would be a good item to add for strength.