Fully adjustable plate-type LSD tutorial

[RC 2NR]

EDIT: Requires all wheel drive

Well, the other day I had the idea to make an LSD that used plates (like many drift cars do). The advantage of this is that it's adjustable by tightening the three screws. I used the AWD ball differential, but I guess you could use one of the gear diffs with a little modification. This mod (if done with the ball diff), is fully reversable, if you don't like it.

The "plates" I used are three metal washers, you can see them in the pic below, here are the specifications:

-Width: 3/8"
-Thickness: 1/32"
-The interior diameter isn't very important, but it's 3/16"

I took out the middle peice of the diff, as well as the five ball bearings.

One of the most important steps is to use some good lubricant between all the plates. Otherwise it will be too tight, and will basicaly be a locked dif. I used this lubricant (http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=64-2301).

These are all the peices I used:

[RC 2NR]

The great thing about this is that it's adjustable from as free as the ball diff, to locked. :D

You must turn all three screws the same amount.

As you can see from the pic all you have to do is take one wheel off to adjust it. :)

[Silent_NightR34]

i like the idea...maybe you could put a piece of paper in between each one to act as a fricton disk...where did you get the washers from?

[RC 2NR]

The washers have enough friction in between them, especially because you can increase the friction by tightening the screws.

The washers are just some that happend to be lying around, I was lucky that they were the exact width and thickness I needed.

[suprafreak33]

cool idea

[NissanGTR01]

thats a good idea but what i did with mine is i left the balls in and just took the little mounts that the screws go into and shaved them down a bit and you get the same effect but if you want fwd then all you do is pull the one tire off and loosen them up and voila fwd or you can go almos as tight as locked it all depends on how much you shave down the little mounts

[neurokinetik]

This is a good mod. http://www.tinyrc.com/forums/images/icons/icon14.gif

[RC 2NR]

Originally posted by neurokinetik
This is a good mod. http://www.tinyrc.com/forums/images/icons/icon14.gif

Coming from you that says a lot. Thanks. :)

[RC 2NR]

I meant to upload this earlier, here is the diff installed.

[spinitsidewayz!]

not to kill the idea or anything but if you loosen the lsd enough wouldnt it slip and lose power instead of sending it to the wheels? i am running tamiya washers that are 1/4th inch in my stock gear diff with all the gears in. its fully adjustable. b4 when i ran it w/o the gears and the plates inverted the thing just slips:rolleyes:

[spinitsidewayz!]

heres the set up im running now. ive been messing with gear diffs for a while. ive never worked with a ball diff so i wouldnt know how it would work but thats a nice diff you have there;) all we need now is a fully adjustable suspension:D

[RC 2NR]

Originally posted by spinitsidewayz!
not to kill the idea or anything but if you loosen the lsd enough wouldnt it slip and lose power instead of sending it to the wheels? i am running tamiya washers that are 1/4th inch in my stock gear diff with all the gears in. its fully adjustable. b4 when i ran it w/o the gears and the plates inverted the thing just slips:rolleyes:

Well, the reason I even have the ball differential is because I have the AWD kit :rolleyes:. When I loosen the diff. more power goes to the front wheels, reducing oversteer, and increasing understeer. When I tighten the diff. there is less slip between the back two wheels, which increases oversteer, and decreases understeer.

When tightening or loosening the diff. a very small amout will drasticaly change how the car handles. It takes a lot of experimenting to get the desiered amount of slip.

[spinitsidewayz!]

yeah it does take alot of adjusting to get that desired setting. hmm i c now how you set it up. kind of like a front biased all wheel drive. so ur rear diff is also doubling as a center differential sort of in a way as it adjusts power distribution between the front and rear. nice. i didnt think of that lol. im running rwd. GO 2WD GO!!:D

[RC 2NR]

Originally posted by spinitsidewayz!
so ur rear diff is also doubling as a center differential sort of in a way as it adjusts power distribution between the front and rear.

Yeah, just not that versitile. You aren't actualy giving the rear more torque, it oversteers more because the rear wheels are locked or almost locked, which is why it oversteers.

[spinitsidewayz!]

so what are ur suspension/tire/diff settings right now and on what kinda surface?

[RC 2NR]

Originally posted by spinitsidewayz!
so what are ur suspension/tire/diff settings right now and on what kinda surface?

It depends on what I want to do:

Drifting:
-Suspension: Stock
-Tires: Hard slicks
-Differential: ~0-5% slip

Racing:
-Suspension: Stock
-Tires: Soft slicks
-Differential: Hard to say exactly, you have to experiment

Both are on a smooth concrete slab.

[Vagabond]

For racing, i would suggest that you leave the diff loosen a bit. This will help with the turning radius. If you prefer understeering, you can tighthen it, or loosen it if you want oversteer. It's all up to your driving preference.

I've been using a rubber O right from Tamiya's Mini 4WD, just cut it to a desire size and put it in the diff.

[RC 2NR]

Originally posted by Vagabond
For racing, i would suggest that you leave the diff loosen a bit. This will help with the turning radius. If you prefer understeering, you can tighthen it, or loosen it if you want oversteer. It's all up to your driving preference.

I've been using a rubber O right from Tamiya's Mini 4WD, just cut it to a desire size and put it in the diff.

Of course you have to have it slip when racing and when you have grippier tires on, or else the car will understeer badly.

As for tightening or loosening the diff, actualy it's the other way around, as you loosen the diff. each back wheel won't have enough friction against the middle plate, so the lost power goes to the front wheels. As you tighten the diff. the back wheels barely slip (or don't slip at all) which causes oversteer. The reason is when turning, the diff. forces both wheels to go at almost (or the same) speed, that causes oversteer.

[spinitsidewayz!]

The reason is when turning the diff. forces both wheels to go at almost (or the same) speed, that causes oversteer.

from my experience you also get heavy understeer with a tighter diff, mostly at higher speeds when you try turning in off throttle. the diff fights to keep the wheels at the same speed. could be a rwd thing.

[RC 2NR]

Originally posted by spinitsidewayz!
from my experience you also get heavy understeer with a tighter diff, mostly at higher speeds when you try turning in off throttle. the diff fights to keep the wheels at the same speed. could be a rwd thing.

No, it's not just a RWD thing (it's worse with AWD), you have to put less grippy tires on the back and stickier tires in the front, also moving the batteries to the front helps.

With drifting, I just use hard slick all the way around...the oversteer is essential when drifting with accel off and power over (the styles I use).

[geofroley]

So all you do in this mod is replace the bearings in the diff with the washers?

[RC 2NR]

Yeah, basicaly.

[civic freak]

for quicker adjustment i leave the wheel on and just stick my screwdriver through the spokes or whatever you call 'em;)

[slideways]

to anyone who cares, i have diff plates for sale they're a little pricey but it's because of the material. they are custom machined out of a high temp alloy called inconel. this metal is really tough, they use it on space shuttles and air force jets. the plates look really cool they are 3/8" wide, 1/32" thick, 1/8" center hole, and eight 1/32 holes around the center hole. i wish i had a good digital cam to take a good pic of these.

if u r interested in this product email me at krylonkid@msn.com

btw, to the members of this forum, i will sell these cheaper than i would on ebay. thanks

[aperson]

what would happen if you left the balls in?

EDIT: nice mod. nevermind the question. and the other 2 that i deleted. damn dialup. takes so freaking long for pictures to load.

[geofroley]

She'd get pregnant:D :D . You wouldn't be able to perform this mod with the ball bearings.

[aperson]

Originally posted by geofroley
She'd get pregnant:D :D

ROFLMAO


ahem, im ok now. he he he.

[aperson]

how about putting one in the front and rear? i just got another AWD kit today (front u joints, diff and cone gears wore out) and i was wonering what it would do? just give me even more adjustability right? did you leave the washers that were originally in the ball diff in or did you take them out?

[aperson]

well i did some testing yesterday and this is awesome. i used one in the front and rear, and i tighened them both up well the wooden deck was wet and the thing flew. before this mod two of the tires would spin and the car would go nowhere, but now all 4 tires spin and the thing freaking flies. when it dried up i loosend them up a bit, just enough so that one tire can spin the whole system.

[xmodrifter]

i just performed this mod on my supra. it is RWD and something doesnt sound right. it sounds like the pinion is rubbing the diff pretty bad. since the middle plate is gone, the pinion hits the 3 screw shafts as they come around. what should i do?

[lancer11]

i got a question wat is LSD

[spinitsidewayz!]

xmoddrifter: does your car lag alot on launches? i think you have excessive gear play involved too... you might want to stick to a gear type lsd for a 2wd xmod so you dont get that slip and lag.

lancer11: LSD is, Limited Slip DIfferential, basically an lsd tries to keep both drive wheels spinning at the same speed or at a limited difference, hence the name limited slip differential. why would you want this?
-first you want to know why we have differentials.. basically when you turn the inside wheel turns slower then the outside. if you had no diff just a solid axle youd have alot of wheel hop and would find it hard to turn... if it snows where you live u'll find urself sideways into trees and such too... most street cars are equipped with open differentials. basically free gear diffs.. open diff does have its disadvantages...
-if you notice on cars not equipped with lsd, open diff the inside tire wants to spin from loss of traction due to the weight being shifted to he outside tire.. this usually gets you scrubbing tire and really messing up track time. drag racing and burnouts youll notice your car will want to leave only one tiremark..
-why not just have no diff and go locked? its really a pain to drive around with a locked (usually welded) differential. car vibrates and wheel hop. u'll notice in xmods the car will corner very unpridictably... and so lsd's bridges the gap.
there are different types of lsd's as well.. viscous, helical, clutch and so on... which in almost all cases will cost you a pretty penny... good ones usually run about 1k. they all pretty much have the same purpose... prevent pegleg burnouts and diffing out.
-if you want to take it to extremes, drifters use lsds to keep both rear wheels spinning and to keep slides going... (with open diff. all you are doing is dragging one wheel and burning the other....) (goddamit i want the 1.5 way kaaz unit!!! >__<. ill stop ranting now:))

[carslothe]

I made a lsd for my x-mod by packing grease in the dif-case. If you use hevey enuf grease you will get a lsd. I used the stock grease that came with the car and find it to light.I'm considering
going to crapy tire to buy thicker stuf and maybe try 5th wheel grease. If you try this becarefull not to get any grease outside the case. It would be like pouring tar in your car motor, so clean the out side of the diff-case before installing it in your car. this is one way you could make a lsd for your x-mod on the cheap.
the other guy's method useing plates sounds like a viscuse clutch diff and might be better than my idea. good luck.:p

[spinitsidewayz!]

grease in the differential has already been tried. doesnt pack enough lock and wears out quickly. metal plates/disks work much more effectively yet sometimes not as smooth. and for note: viscous lsd = "liquid lsd". found optional on some rwd cars and doesnt lock for crap...

[carslothe]

yea your'e right about the grease I used being to light but the trucking industry has a grease for their 5th wheel plates (the big flat greasy on the back). This stuff is thick and your goal is not to lock your dif but put resitance in it.

[RacinSkillZ101]

i honestly like this mod, im using it up front and in the back, whats great about a plate type lsd is i can adjust each diff form no power transfer to fully locked... also allows you to switch between FWD, RWD, AWD and NWD "No wheel drive" in other words have both diffs opened completely so no power is transfered and your motor just revs, i know its not practical but it would be cool

[color0]

Originally posted by spinitsidewayz!
grease in the differential has already been tried. doesnt pack enough lock and wears out quickly. metal plates/disks work much more effectively yet sometimes not as smooth. and for note: viscous lsd = "liquid lsd". found optional on some rwd cars and doesnt lock for crap...

i have a liquid lsd... except i used silicone sealant... it locks pretty readily. but if the liquid you refer to is like grease or vaseline, etc. then yea, it's ineffective.

but silicone works well, provided you don't put in too much and lock the diff up.

[carslothe]

ofna rc has dif locking oil from 1000wt to 120 000wt.

[color0]

which weight would seem appropriate for xmod diffs?

i read that satokatsu or one of his friends used 30,000 weight oil i think. not sure, need to check the website back.

*edit* driver was R.P.K.48, and the 30,000 weight oil is confirmed.

[Silentbob343]

I've got some questions:

I just installed the AWD kit and was wondering what is the difference betwen the two red diffs in the kit.

I know the rear diff uses ball bearings and I'm guessing that the front diff uses cone gears like the old white rear diff. Am I guessing correctly?

What would happen if I put ball bearings in the front diff? I was thinking of doing the washer mod to the rear diff and using the ball bearings in the front.

[RacinSkillZ101]

ball bearing diff is a lil more limited than the gear diff. the washer mod is superior to any rs diff, and is adjustable.

putting the bb diff in the front is a good idea because it will offer good straigh line speed, but is open enough to still let u turn

[color0]

ok, so now i'm experimenting with thin sheets of silicone, maybe this will give some lsd effect.

[L0ne wolf 72]

another really cheap way to make a locked diff. super glue the gears together. =P they'll never move and you'll have a fully locked diff!! lol i might actually try taht...

[bFranck]

what is the minimum inner diameter that could be used?

[color0]

inner diameter? 3mm, probably. it's gotta fit around the xmods shafts.

[nerobro]

when experimenting with the diffs on my mini-x and mini-z I foundthat vaseline was an excelent diff lube. It provides dampening that most other diff lubes don't.

Those "locking diff lubes' that wre mentioned are for gear type differentials. Not ball differentials. for the reccord, this kind of modification should be for ball diffs only. :-)

I will be adding a small o-ring to my ball diff tonight to see if I can get some semblance of adjustablitity out of it. Most ball diffs use a single screw through the middle to hold them togother, and then there's a spring of some sort to provide some progression to the force on the diff.

The ball diff as it comes from ratshack is very very poorly designed, they also tell you to put it in the wrong end of the car.

In a 4wd car without a center differential, you should be running an almost free (as in very loose) differential, or even a one way bearing up front, instead of the very tight ball diff out back, and a gear diff up front.

[NEO-R]

too bad yu can't do this on an EVO car 'cause the rear gear diff is pressed together so yu can't even pull it apart without completely ruinin' it.