From experience, sjcrss knows his diff well. It was cheap to make, and I would highly reccommend it. The stock diff is junk!! Also, since credit is being gave here, was it not my idea to put the 1/8 directly into the case dude? LOL

gotta bust my chops eh...it was YOUR idea...I just implemented it...lol, and figured the in' & outs on how to make it work...Thanks T

So just to make sure we are clear: neweuser came up with the idea, mistercrash created it all, and sjcrss ripped it off and tried to take credit for everything? sounds about right :wink:

Anyway, just got the last required parts today for the Thunder Tiger hybrid version. Hopefully will start the build soon, so expect some questions all you guys who've already made one of these.

LMAO, thats a good one....hehehehe.... Newe and I we talking and he had a idea to put a 1/8 scale diff in the erevo, but kinda like the original slipperential, I then decided to see if i could make one fit into the erevo tranny, and did some fitting ect. and came up with the design I used and supplied to MC, he made a great tutorial on how to make the diff...however MC did come up with some design tweeks of his own, that i will not take credit for, cause they were his idea's.... this about sums it up...

[QUOTE=simplechamp;316590]So just to make sure we are clear: neweuser came up with the idea, mistercrash created it all, and sjcrss ripped it off and tried to take credit for everything? sounds about right :wink:[QUOTE]

Delusions of Grandur right there nooby...if you peep sjcrss's sig, you can plainly see there the ideas. In fact, I wanted to stick a 1/8th diff in an FLM tranny case for years. Just never took the time to do it and Mike came out with the slipperential anyways, so there was no need for one.

[QUOTE=neweuser;316700]Delusions of Grandur right there nooby...if you peep sjcrss's sig, you can plainly see there the ideas. In fact, I wanted to stick a 1/8th diff in an modded FLM tranny case for years. Just never took the time to do it and Mike came out with the slipperential anyways, so there was no need for one.

thanks T, well i think enough about who did what or when...I can supply info as well as MC...... I think credit needs to go where credit is due....so here goes.....
Original Idea 1/ scale diff in FLM case...newe
1/8 scale diff in erevo tranny ( I made up theplans ect. and did all the test fitting ect.) ...sjcrss
shaft re-design's and other gear mods...ect plus new ideas for the cd design...MC
this being said everyone is getting credit where it is due.....

IMO, who cares! lol It works!

[QUOTE=neweuser;316701]It was a joke, hence the little winking icon.

I just started making my center diff. Today I ground down the center spur gear. It was suggested to me to use a nut and bolt assembly to chuck the spur into a drill press, then use an angle grinder while the drill press rotated the spur. I didn't have an angle grinder, so what I did was chucked the spur/nut/bolt assembly into a hand drill and used that to spin the spur while I ground it down against a bench grinder. Probably took longer than using an angle grinder, but it worked out fine.

Not sure if I took off enough yet, but I was concerned about grinding too much off of the outer lip and making it too weak/brittle. Is this going to be a problem if I left the modified spur like this?

http://i47.photobucket.com/albums/f1...3/P1020350.jpg

It looks ok to me, one thing i did, is I determined the cap overhang, per the gear mounted to it, but it looks good so far

Not sure what I want to do next, maybe cut and drill the Traxxas output shafts. Thinking of sourcing a local machine shop to drill and tap the holes in the cap because I don't want to screw it up and bust off a tap in the hardened steel.

are the spurs made from hardened or high speed steel?
cause i could use the lathe instead.

The Thunder Tiger spur used in mistercrashes revised design is hardened steel, which is what I am using. I'm not sure what type of steel is used in sjcrss' original Hyper 7 version.

I think it's hardened steel as well,....thats what my machinist told me at least...

I am pretty sure that all good diffs and center diffs like Ofna, Thunder Tiger, Losi, Mugen and so on use hardened steel spurs and ring gears. That CD is starting to look good simplechamp, if that lip is still too thick and you run into fitness problems in the tranny, you can take off a little more and I'm sure you won't have any problem. The lip I left on my CDs are like half a millimeter thick, it's just there to center the piece on the diff case.

I wish someone could make these gears for $5 each :mdr:

http://i177.photobucket.com/albums/w..._gear_top1.jpg http://i177.photobucket.com/albums/w...ar_bottom1.jpg

Nice mistercrash! I was actually planning on trying out just the two mounting screws instead of four, we'll see how well it holds up, my main reason was to have less holes to drill and tap. Also was debating countersinking the holes where the mounting screws go, but not sure if the material is thick enough.

You pretty much read my mind on that drawing!

EDIT: Can I get some advice on drilling the pin holes in the cut-down output shafts? What size bit is used? (I have a bunch of SAE bits, not so many metric) How do you drill the holes exactly on-center? How far from the end should they be drilled?

This is how I do it.

If you're going to have a machinist make the holes in the spur gear and thread them, maybe he/she can make the holes in your shafts also.

That's something that had crossed my mind. Probably would be the best. Do you have a measurement for how far from the end of the shaft the hole needs to be?

Modded the plastic spur tonight and it turned out well. All I have left to do is cut down the output shafts and then after the long weekend I'll call around to a few shops to see what they'll charge to do the drilling and tapping. Unfortunately I have a feeling this is going to turn into a $90 center diff, but no turning back now!

It will be worth it, trust me....you will notice a difference

You are so right scjrss, the 8th scale diff in the ERevo is so efficient, tough and so tunable. According to my my calculations, the center of the hole in the shafts are 0.229'' from the tip.

Mc, any updates on the aluminum slipper disk?

yep! I'm still running the same disk I made, it wore down by about 1/2 of a millimeter. I had to readjust it a couple times when it started slipping too much. It is still working awsome and I love it.
remember that Losi center diff I made with the three aluminum posts, I plugged two of the holes in the diff cap with JB Weld and made a new hole to install the TRA3985X output gear with only two posts like the last CDs I made. Now I have two CDs made with the heavy duty Losi LST XXL diffs. I will see if the JB Weld plugs hold up. I have been running this last Losi heavy duty CD with the two aluminum posts and TRA3985X output gear every day since I made it and it's working really really well. I'm happy about it.

thats great news, hopefully everything will continue to hold up well. Mine is still holding on strong, and no leakage that i can tell, but after the summer ends, im due for a complete teardown anyways

Just need to contact a machine shop now to have them do the drilling and tapping. Once that's done I'll drill the two holes in the plastic spur and assemble it all. Slid the shafts into the spur/case just to test alignment and everything lines up perfectly. I bored out the center of the plastic spur and then also counter-bored a larger section to allow the metal cap to sit flush on the spur.

http://i47.photobucket.com/albums/f1...3/P1020356.jpg

http://i47.photobucket.com/albums/f1...3/P1020352.jpg

Lookin Good Jason !!!!
For a realive newcomer to the Hobby your jumping in with both feet, Great job Bro !

I used a lotta jb weld on mine. I had my friend mill out the weld for placement of an internal bearing inside the case. It is ultra sturdy and i've bashed the crap outta this thing and it's still hella strong never had to rebuild it at all except to put in 500k oil:

If I use an 8x12 bearing on the diff cup side and a 6x12 on the spur side it should fit in the stock trans case without any mods right? (except a little shimming)

Urgeoner did you use the JB Weld so you could have a larger bearing?

I wanted to use the bearing that fits around the steel end of the diff case so yes. I shimmed a bit much initially and it wasnt that strong so I JB'd it up.
I also used a bit of the 3/4" black plastic spacer found on the regular fixed output shaft. You can see it in the first picture, it helps with the end play by further reinforcing the output shaft.

SC, thats correct, use the 8X12 on the diff cup side, and into the tranny case, and use the 6x12 on the gear side and use a few shimms to take up any play between the gear and the bearing, and you should be all set. This was originally set up to be a easy design for anyone to be able to make a 1/8 Cd for the erevo tranny. What is everyone's input on this..... Did I manage to make it simple enough, with the exception of drilling & tapping the ring gear, and the 2 holes for the output shafts? Let me know....

I'm not very experienced in the workshop but it's been smooth sailing so far (with the help of all you guys of course). I'd say the reason I'm not doing the drilling/tapping myself is half lack of experience and half lack of proper tools. If I had access to all the tools a machine shop has I'd probably give it a shot myself.

I'm a little more comfortable with the idea of drilling the shaft pin holes, but since I'm going to use a machine shop for the hardened cap I might as well let them drill those too, since they can better ensure a dead-center hole. Also, costwise it will probably be the same, since it's such a small job and they'll probably have a min charge of 1-2 hrs labor which should be plenty of time to do the work.

I think it would be good to start a new "official" Revo hybrid center diff thread that could even get stickied. Right now there's lots of info floating around, but it's scattered through many different threads. We should work on a new write-up and bring everything together into one.

I agree, all the info would be nice if it was organized into a single thread & stickied as well, that way a person can find the info easier and build one themselves. Also a big thanks to MC for his ideas and improvements as well. Fortunately for me I was able to have a friend, who works in the machine shop where I work , and he was able to drill & tap the holes for me, and I was able to do the holes in the shafts myself

+1 :yes:

I started a official thread for the info, let me know here if i missed anything, and I'll add it to it...Hope i got it all and that it is helpful to everyone as well