Mojave Why are so many swapping to an open diff from LSD on their Mojave EXBs?

[Knightfall]

I see many threads and videos about how to swap to an open diff from an LSD, but I haven't caught on as to why. There are some videos I've watched about the difference between open, LSD, and even locked diffs, but many of these lead me to believe LSD would be better for the Mojave. And I'd assume Arrma thought so as well if they changed to LSD for the EXB from the open diffs in the RTR.

Can someone "explain like I'm 5" why so many want to make their rear diff open?

 

[SrC]

I prefer all 3 of my diffs to be OPEN. I use the RTR open diffs ( 6s only) Best control. Easier to work on and dial in. With Open diffs ( RTR's), the Diff oil thickness is used to dial in a good balance of front, center, and rear Power Bias. Running 60k F/500K Center/ 30 k Rear CST oil is best. What I use in my RTR Mojo, Kraton and Noto. Many run this in Open diffs.

With LSD diffs, it is the Staging of the LSD Plates that control the diff action. There are 2 staging positions for adjusting the "Slip"( Diff action)
Not so much the Thickness of the Oil (CST). LSD diffs run thinner oil weight for this reason. Harder to control. Driving feel is way different.
Absolutely an Open Rear diff is where to start first if considering, Then the center next. IMHO.

But.... to me, the main advantage of the LSD diffs are that the LSD (EXB) F and R Main and Input gears are very robust and stronger than the RTR Open diffs. Probably most important at the Rear. Since Rear main/input gears wear out first from my experience. More so with 8s electrics.
You have Two options here for Open diffs:

1. Get the Arrma Option LSD "Open Shim Kit" to convert LSD's to Full Open. Maybe best for 8s Power. Need to thicken the oil considerably when doing this.

2. Just use the RTR standard Open diffs. They cost much less FWIW. At JennysRC. Complete RTR open diffs.
Hope this helps.

 

[Knightfall]

I prefer all 3 of my diffs to be OPEN. I use the RTR open diffs ( 6s only) Best control. With Open diffs ( RTR's), the Diff oil thickness is used to dial in a good balance of front, center, and rear power bias. Running 60k F/500K Cneter/ 30 k Rear CST oil is best. What I use in my RTR Mojo, Kraton and Noto.

With LSD diffs, it is the Staging of the LSD Plates that control the diff action. Not so much the Thickness of the Oil (CST). LSD diffs run thinner oil weight for this reason. Harder to control. Absolutely an Open Rear diff is where to start first if considering, Then the center next. IMHO.

But.... to me, the main advantage of the LSD diffs are that the LSD (EXB) Main and Input gears are very robust and stronger than the RTR Open diffs.
You have Two options here for Open diffs:

1. Get the Arrma Option LSD "Open Shim Kit" to convert LSD's to Full Open. Need to thicken the oil considerably when doing this.
2. Just use the RTR standard Open diffs.
Hope this helps.

So there is no rough equivalent between an open diff and an LSD at all? I would think an open diff with 30k would be the same as maybe an LSD with the minimal resistance setup and 10k or something.

It would be nice if there was a chart or something comparing the two. (If I had the coin and time to buy a bunch of oil weight and another diff I'd consider this.)

 

[Surchaufeur]

I kinda like the tune Lsd peovide for the center diff. The front idk. I don't do LSD in the rea but i might on my notorious. A bit of understeer and rolling over

 

[21STalion]

LSD or open doesn't matter too much. Hardcore tuning the open is far superior because it stays more consistent. I find the LSD to be less predictable and therefore less tunable.

Won't make much difference either way

 

[Matt05]

I’ve been setting my lsd diffs in the open configuration using the method I think @HZRDOS came up with? Uses a combination of shims/washers and the lsd star plates.

On edit it might have been @Engineer idea.

 

[SrC]

So there is no rough equivalent between an open diff and an LSD at all? I would think an open diff with 30k would be the same as maybe an LSD with the minimal resistance setup and 10k or something.

It would be nice if there was a chart or something comparing the two. (If I had the coin and time to buy a bunch of oil weight and another diff I'd consider this.)

There is no equivalent functional comparison to be made between these 2 types of diffs. Under load, they operate Differential action differently from each other. They are are dialed completely in different ways.

 

[BashingBrian]

Personally I don’t think these toy car diffs act like real world lsd’s..!!
I run all my exb’s with open rear diffs as I feel it makes the diff behave more naturally and as @SrC says the EXB diffs biggest advantage is the bigger stronger pinion and ring gear..

 

[SrC]

I kinda like the tune Lsd peovide for the center diff. The front idk. I don't do LSD in the rea but i might on my notorious. A bit of understeer and rolling over

+1

 

[Knightfall]

So the take-away I'm gathering is the swap from LSD to open is more about seeing tuning changes better. I'm not seeing anyone saying an LSD has less or more control offroad, or if one has more/less oversteer than another.

Next question...​

For anyone who kept their LSDs as is, what's the highest oil weight you've used? Which plate setup did you go with?

 

[BashingBrian]

I truly think the main reason people changed them originally was because they were broken from the factory at the beginning no one could get parts so everyone needed a solution, I wrote a guide as to how you could make it an open diff with normal shims and came up with a solution for running an open diff at the time.

 

[Surchaufeur]

So the take-away I'm gathering is the swap from LSD to open is more about seeing tuning changes better. I'm not seeing anyone saying an LSD has less or more control offroad, or if one has more/less oversteer than another.

Next question...​

For anyone who kept their LSDs as is, what's the highest oil weight you've used? Which plate setup did you go with?

100k highest

 

[Moirae]

I have 200k in an lsd center diff right now in my stretched typhon. Though half the diff is "open" and the other half has LSD plates lol.

 

[21STalion]

I went open middle and rear on my Talion EXB. Stuck 1M in the middle and it hauls a$$

 

[KevinC]

I had schit luck with LSDS off the bat but I got ‘em dialed in now. Probably because I didn’t pay enough attention to the “rounded side facing in” on the plates.…..that and proper shimming. I also use minimum effect setup on the plates. Set your diffs up dry first and test for binding before putting oil in. (Ask me how I know)

I use 10k rear, mix100/200k centre, and 20k front. The LSDs are cool but there’s more moving parts which sometimes equals more milk that can go sour.

cheers,
kev

 

[SrC]

+1

LSD diff action at the Center makes the most sense. I agree.

 

[Dan B.]

I kept the stock EXB LSD’s in my Mojo. Max effect front and center, min effect rear. I like this setup with stock weights. I did have min center effect, but went to max effect to try and tame front ballooning. It helps a little (nothing like a spool or locker, though) and bashing off road is fine. This setup did seem to make it much more prone to rolling on the street, though. I now keep to the Typhons for any on road use.

 

[wadedog]

I’m running a full locked rear diff with no problems but I’m just speed runs with it was having problems with the open diff

 

[Dan B.]

I’m running a full locked rear diff with no problems but I’m just speed runs with it was having problems with the open diff View attachment 232337

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Interesting. Why? Most seem to prefer an open rear diff for better stability. As for speed runs, many run a locked center, a spool, or super high fluid rates as well as max LSD (on EXB diffs) or very heavy weights on the front. Interested to hear your feedback.

 

[Dan B.]

Personally I don’t think these toy car diffs act like real world lsd’s..!!

I think they kind of do, if we’re talking apples to apples. In the real world, it’s really common for people to refer to torque biasing differentials (like Quaife, for example) and actual LSD’s as the same, which isn’t the case at all, they behave very differently. If I set the plates of the rear LSD diff in my Mojave EXB to max, it’s almost like having really heavy fluid or earplugs in an open diff. Both tires spin equally, even on pavement. On grass or gravel, you’ll see equal length lines from the tires on WOT acceleration. Which of course sucks for handling in anything but a straight line. That’s why I run my rear diff to “min” on my EXB, and run open rear diffs on everything else.