Official Erevo 1/8 scale center diff thread - Page 4 - RC-Monster Forums

mistercrash · 09.27.2009, 11:13 PM

Well I changed what I called ''the last CD I will make'' for my ERevo. I used Axial posts instead of the Kyosho ones. The Kyosho ones are well suited for a CD made for the nitro Revo tranny because they are 5 mm in diameter and they fit better in the small 28 tooth gear that has to be used. But they have to be cut to the right length. The bigger TRA3985X 33 tooth gear of the ERevo CD works very well with these 7 mm diameter posts from Axial and the posts don't have to be modified in any way. But the output gear is drilled with a 9/32'' bit to slip over the Axial posts.

shaunjohnson · 10.05.2009, 05:49 AM

just ordered the parts to do the LST diff conversion.
going to differ it a little bit by using the OTHER black outdrive gear from the revo and going to make custome posts on the lathe.

simplechamp · 10.05.2009, 12:40 PM

Well I got the hybrid center diff installed no problem. I started to do the F/R RCM hybrid installs but I'm having issues, so I'll probably just keep the stock F/R diffs in so I can get some driving in and then work on the RCM hybrids over the winter. I ended up filling the center hybrid up with 50k silicone oil. I'll report back once I get some driving in, maybe even later today if the weather holds. I want to try to unleash the punch control on the MMM a bit more and see how the center hybrid diff handles it.

shaunjohnson · 10.05.2009, 04:35 PM

you dont understand how close i was to getting a losi smart diff for conversion, same principle just a little more $.
hope to have smart diffs all round one day i think

simplechamp · 10.06.2009, 12:54 PM

Quote:

Originally Posted by shaunjohnson

you dont understand how close i was to getting a losi smart diff for conversion, same principle just a little more $.
hope to have smart diffs all round one day i think

I almost tried an Ofna Spyder diff. Might still do that, or look at a Torsen diff.

suicideneil · 10.07.2009, 12:29 PM

I've seen quite a few people mention the torsen diffs dont handle BL power all that well, plus they work the opposite way to a normal diff; instead of sending excess power to the fronts to prevent wheelies, they send all the power to the rear wheels (if used as a center diff)- not good for handling...

Semi Pro · 03:42 PM

Quote:

Originally Posted by suicideneil

I've seen quite a few people mention the torsen diffs dont handle BL power all that well, plus they work the opposite way to a normal diff; instead of sending excess power to the fronts to prevent wheelies, they send all the power to the rear wheels (if used as a center diff)- not good for handling...

have thouse people tired them?

i have torsen diffs in 3 of my brushless conversions (2 buggys and a truggy)and all of them show very little wear

i think the people who are haveing problems are either building them wrong or not changeing out grease often enuff

and as for putting power thrugh them, im running 5 and 6 cell, when set up right they work the way they should, my 8ight will lift the wheels about 2 inches for only a second when leaveing the line but its a hell of alot faster launch than balloning the front tires.

molak · 03.22.2011, 04:03 AM

Quote:

Originally Posted by suicideneil

I've seen quite a few people mention the torsen diffs dont handle BL power all that well, plus they work the opposite way to a normal diff; instead of sending excess power to the fronts to prevent wheelies, they send all the power to the rear wheels (if used as a center diff)- not good for handling...

Torsens dont work that way, a torsen diff has the ability to bias the torque without any slipage. It can bias up to 3 times more torque to one axle than the other.

On acceleration it will send up to 3 times more torque to the rear. After that ammount the front will start to slip (or lift!) and If an axle is on the air it can transmit any torque and 0*3 = 0. In theory is impossible to pop a wheelie with a center torsen..

A viscous differential will send equal torque to both axles until one loses traction, at that point it will start to send power to the axle with more grip according to the viscosity of the fluid and the difference of speed... And it will do so on and off power, while torsen in off-power acts as an open diff, improving both on and off power turning...

If the available torsens can stand the torque of a MMM they will be ideal!!!

shaunjohnson · 10.15.2009, 05:19 AM

well my LST diff turned up.
my mate got a losi smart diff for xmas pressie to himself for later conversion.
i reckon we'll put that in the front depending on how much we like the LST center diff.

i'm not going to use the carbon fibre on mine as the gear already has one side blocked over with plastic, this is what the carbon fibre would do in the other setup.

i'm going with this setup...
http://s177.photobucket.com/albums/w...t=losi_cd2.jpg

my only concern is that it will be a pain to dissasemble.

mistercrash · 10.18.2009, 11:01 AM

Quote:

Originally Posted by shaunjohnson

i'm going with this setup...
http://s177.photobucket.com/albums/w...t=losi_cd2.jpg

my only concern is that it will be a pain to dissasemble.

That set up is a pain to assemble and disassemble. I suggest you go with the last system I did in post 46.

shaunjohnson · 04:38 PM

Quote:

Originally Posted by mistercrash

That set up is a pain to assemble and disassemble. I suggest you go with the last system I did in post 46.

i began building it that way, but i decided yesterday to change the plastic gear.
rather than using the solid tranny 5 spoke gear, ive switched to the trx revo center diff gear.
that will make things a little easyer for me

more even screw spacing then.
how on earth did you drill holes in your "cap" cause i actualy DE-hardened mine, heated it up then let it cool in cement dust for 24 hours. i can drill mine now.

simplechamp · 10.18.2009, 06:59 PM

Quote:

Originally Posted by shaunjohnson

how on earth did you drill holes in your "cap" cause i actualy DE-hardened mine, heated it up then let it cool in cement dust for 24 hours. i can drill mine now.

As previously posted I actually had my local machine shop tell me they couldn't even do it. Ended up spot annealing and using a pure carbide bit as suggested by mistercrash and it was a piece of cake. I'm kind of interested to see how it would be drilling an un-annealed cap, just to compare it and see how much the annealing helped. Also used a cobalt tap for the threads, but depending on what design you follow you might not need to tap at all.

shaunjohnson · 06:06 AM

Quote:

Originally Posted by simplechamp

As previously posted I actually had my local machine shop tell me they couldn't even do it. Ended up spot annealing and using a pure carbide bit as suggested by mistercrash and it was a piece of cake. I'm kind of interested to see how it would be drilling an un-annealed cap, just to compare it and see how much the annealing helped. Also used a cobalt tap for the threads, but depending on what design you follow you might not need to tap at all.

if un-annealing means un-hardening then it was fine to drill with.
just heat up till red hot, then cool as slowly as possible for 24 hours (cement dust works a treat) and then drill with a standard drill bit.

edit: first LST diff in final stages now, i ended up using the traxxas center diff gear on the LST diff instead as that is what i had on hand. will fill with 100k oil then go try and kill it on 6s

shaun

mistercrash · 10.18.2009, 07:45 PM

Quote:

Originally Posted by shaunjohnson

how on earth did you drill holes in your "cap"

I used carbide drill bits and a carbide counter sinking bit like SC did.

miniGranis · 03:15 PM

Is anyone intersted in selling a 1/8 center diff that will fit a nitro (3.3) tranny ?
I dont have the skill, stuff or time to do one myself.