Is LSD same as Ball Diff?
 

Im just curious...

I mean, if I'm using ball diff which is partially tightened,
do I experience the Limited Slip Diff effect?

Is LSD good for 4wd or front wheel drive or rear wheel drive?

A ball diff behaves more or less in the same way as a limited slip diff. The "limited slip" effect can be adjusted by running the diff tight or loose. Most people prefer a loose (free) diff.

loose diff wont cause d car lose acceleration speed?

Of course a loose diff will affect the acceleration, because there will be no enough friction to prevent the diff from spinning, i.e. the power will not be completely transferred to the drive shaft. I guess what he meant was under the same condition, people prefer to have a little loose diff so that the differential function can work freely.

ok thanks

tight diff give more steering than loose diff rite?

Yes and no. Sometimes a tight diff gives more steering and sometimes it dosen't. I find a tight diff works better in high grip and a free or loose diff works better in low grip. Generally you start with it free (just tight enuf to resist slipping under normal loads) and tighten up a bit at a time if you think you need it.

Ok. Let me get this straight, it's preferred to use a little loose diff
setting? Won't it defeat the purpose of LSD? So a normal differential
would be better? Like the gear diff of a TT01? Why is that LSDs
are used in race cars anyway when an ordinary diff (loose) is preferred?

@Airflow

it depends where you will be putting your diff. if you'll be placing it up front, most of the time racers prefer it to be a little tighter than usual. if you'll be using it for your rear, it's almost always set to loose to prevent your car from spinning under high acceleration.

I was going to say whatever you do if you want to bias your diffs make sure always that you have more traction (in the diff) up front than rear, never the other way around.

if loose, i think d tyre wont spin but the diff is slipping tremendously rite?...

For stability reasons.. that's always the way to go. However it works just like a real car.. get that front too tight and you will start to understeer somethin aweful. This is especially true under power.

Here's some info on LSD:

http://www.usdoj.gov/dea/images_lsd.html

Absolutely. A very good analogy is to think what happens when you lock the diff on a real car when it's RWD and then FWD and this will actually give you a good idea about two extreme points of adjustment. You need to be somewhere inbetween depending on your conditions.

Yeah.. it's so funny how even on this scale.. you can tune these cars like you would work on a real car. They essentially act very similar minus aero which isn't quite the same given scale and viscosity of the air. :)

But it amazes me how a front spool works for RC. If you think in terms of real cars, you would never attempt to use a locked diff for the front.

I think that works for you guys in the US where you race foams on carpet. Everyone I know who ever tried one here in oz with rubber on carpet said it was absolutely horrendous

Made some research and a 1.5 way LSD is what race cars use generally.
Kinda like it acts like a normal diff but under torque it tightens automatically,
something like that, I think it's adjustable as to when it tightens. Also,
LSDs cure torque steers from rear wheel drive cars.

Im not into RC drifting because I dont like the idea of using plastic tyres
so I dont lock my rear diff. Street racing is what I do so traction and
stability in the straights is important plus good handling for dog fights.
But I also drift when needed. So I just want to apply some race car technology to my rc cars for better performance.

The surface we race on is typical flat street concrete with some slippery
spots because of dust or sand build-up so the condition is loose to medium
traction. When I first got my RTR TC4, its front diff is fully tightened like
a spool and after months of running, it began to have straight line issues,
it would wander left and sometimes right. But when I loosen the front diff,
it tracks straighter than ever before. Surprisingly, my TT01D with stock
gear diff runs the best on straight line, I mean you can point it to the
direction that you want and just let go of the steering wheel.

So basically, an LSD gives you grip on corners? Which will be beneficial
in quick launches, loose, tight or mildly tightened diff?

1.5 way LSDs are open off-throttle and limit slip on acceleration.

Spool is NEVER used with foam on carpet. On the other hand, Europeans are doing fine wit spools on carpet rubber.

LSD is a acid :eek::eek::eek::weird:

well, when i said loose.. it's not "loose" as in the diff would be slipping, but "loose" as in the diff can have/execute differential action easily.

settings diffs for races is more than just "loose for low grip surfaces and tight for high grip tracks". in my case, it has always been just try to drive your car around the track then adjust your diffs according to what you want. i just use the quoted statement above for a good starting point for my diffs.


@Airflow

yes, generally, a looser diff would have much more grip but at the price of speed. the looser you set your diffs, the more it will be prone to slippage, and thus loss of speed. so if you want to have quick launches, then have it "tighter", but again, compromising maneuverability.

I think you're a bit confuse. RWD cars don't suffer from torque steering.

A FWD car needs an LSD on the front to sure understeer not torque steering. The torque steering is somewhat tamed by an LSD but that's not its first purpose. The reason it does cure torque steering to some extent is because LSDs typically induce more drag between gears.

Historically LSDs were used to transfer power to the loaded wheel in street racing when under hard cornering inside wheels tend to lift and unload therefore all torque was transferred to the unloaded wheel making little use of the engine's power.

These days there's a number of LSD and torque biasing diffs used in cars such as Quaife or Torsen. Look them up on the web and you'll see their function and applications. Most FWD cars really benefit from Quaife diffs (such as Peugeot 205 GTIs with hotted up engines and so on). RWD cars also benefit form torque biasing action but that's because in hard racing they tend to lift rear wheels so in such situations a Quaife is the solution (such as on BMW 2002). There are also a number of production cars that come equipped with Quaife diffs from factory such as Celica GT-Four (rear diff).

In the world of R/C there is an italian company that makes Torsen diffs but not for electric 1/10 cars.

Also, as long as you have all wheels on the ground you don't rally need limiting action. In R/C you need some limiting action because you want to correct under/oversteering effects induced by other components in the transmission train, such as more powerful motors, tires, etc.

Tight diff in a FWD RC works best IMO.
when you stear left your right tire wouldn't slip as much as if it was loose. when your stear right your left tire won't slip as much.

4WD cars I would think a loose rear diff would give you more stearing and a more stable feel.

I think a spool runs good on outdoor low grip tracks.