Diff chat: mech LSDs

[SLY33]

ive started this thread as the topic has come up in my suspension thread

please continue...

[Duncan]

Excellent, the other thread was getting out of line

I've got one simple question to get started......why does *anyone* want anything other than a 1 way diff? Under which circumstances do ppl want LSD affect under braking?

[sidewaymambo]

I saw one diagram in one issue of option jap mag suggest that 2 way help drift, since both wheels almost same speed enter apex, then driver will use conter steer to help enter conor..that's use my limited japanese. but maybe mean something else.

Also thanks to Steve post this link

[PRO_32]

Excellent, the other thread was getting out of line

I've got one simple question to get started......why does *anyone* want anything other than a 1 way diff?  Under which circumstances do ppl want LSD affect under braking?

DRIFT....

[Cubes]

How does the conventional diff work?

2 way, 1.5way or 1way?

I would think its 2 way as when compression locking two wheels lock.

Difference is I suppose the conventional diff isn't as tight.

Could a 1.5way diff actually help you corner? Possibly helping the front wheels turn in easier with less understeer? Giving a slight neutral feel if you like?!?

I am in the market for a diff soon. I was thinking about getting the stock diff shimmed up however it makes it basically a locker which is good for drift but no good for general street driving. Any one with experience how tight these shimmed diffs are would be great. I drive to Uni which = lots of U-turns or sharp turns to get in to car parks etc.

[Jay95R33]

Could a 1.5way diff actually help you corner? Possibly helping the front wheels turn in easier with less understeer? Giving a slight neutral feel if you like?!?

G'day Joel,

With my limited knowledge, I would say yes provided you are accelerating.

With my 2 way, there is a definate change between off and on throttle when going around a corner (as SydneyKid has discribed).

Off throttle going into the corner it will understeer a little (but is very easy to control, and on a track you probably wouldn't be driving like that anyway), and once you start to feed the power back on you can feel the back really pushing hard and will induce a bit of oversteer (again, really easy to control).

Sounds hard, but it's very predictable and consistant.

So I'd say that a 1.5 way would tend to understeer less than the 2 way, so for the street and track a 1.5 way would be the best. Although a 2 way would still be better than the stocker.

J

P.S. - the FM901's are getting pretty low on tread of late, and I've been giving them a bit of a hand It's only now I know how predictiable these diff are

[EnricoPalazzo]

well this brings me back to joels question, is the stock diff similar to a 2way, as i was also thinkin of reshimming it.

[Jay95R33]

Nope, the sockie is a LSD (limited slip). So with the stockie it will let both wheels spin at different speeds, but it will just limit the amount of difference between them.

Think of it like this. Stock diff is limited slip, while a 1/1.5/2 way is no slip, it'll lock the wheels to the same speed (if your accelerating enough).

I think that reshimming the stock diff will just make it tighter, so the amount of slip that it lets happen is less ?? Can some confirm this ?

J

[Cubes]

With a stock diff re-shimmed it apparently feels like a locker when turning. Hence the inside wheel chirps and the car squirms around a little. You hear the wheels skipping. Well thats what JMS told me anyhow.

[SLY33]

talking about "lockers" and "LSD's" : why do they seem to go hand in hand with mechanical diffs?

eg: "OS Giken Super Lock LSD" i gather this is a locker diff, so why do they put "LSD" in the title? Isnt it either a limited slip, or a locker?

Re-shimming the stock diff can be customised by the amount or thickness of shims, to give the effect you want. Ive heard of UAS reshimmed diffs over here being great for the street. In probably most conditions other than drifting, i found my stockie to be perfectly adequate for street, and if you dont want a pig of a diff, maybe just get it tightened up a little bit? i think this is possible...

[EnricoPalazzo]

my problem is that it my diff frequenly open wheels when puttin down the power.

Sometimes when i go WOT, i get major traction problems, the car pulls slightly to a certain side to say that they wheels are spining, yet its nothin like an oversteer where the rear end really steps out, it just slighty does. Now in this situation, are both the wheels spinnin, ie can the car pull to a certain side yet only 1 wheeling?

[lindsey34]

when i turn a corner slowly my inside wheel skips and it does not make any noises at all (like clunks), and when going around rounderbouts the car feel like it is pulling back and fowards (a surging feel).

do you think this is locker? I have been told that it may be just a tight cluch, but it skips even when I'm riding the clutch a little.

[Chris32]

Any of you guys running coilovers?

Just thought I'd mention I have recently swapped to a set of coilovers which have been corner weighted and adjusted on the previous car (R32GTSt)

I used to have a problem of spinning one wheel contantly, but after installing the coilovers, the rear seems to be alot better, more even weight on each wheel i guess

It still has its moments though, so I am about to install one of those aluminim cradle bush kits to try and help it put more power through BOTH wheels!!

The diff will be the last thing I look at, as i dont want to transform it into a pig around town and through the hills, as most of my driving is done in either one of those

[EnricoPalazzo]

im runnin tiens. Never ran standard suss, so dont know wat the difference is unfortunatly.

[Cubes]

my problem is that it my diff frequenly open wheels when puttin down the power.

Sometimes when i go WOT, i get major traction problems, the car pulls slightly to a certain side to say that they wheels are spining, yet its nothin like an oversteer where the rear end really steps out, it just slighty does. Now in this situation, are both the wheels spinnin, ie can the car pull to a certain side yet only 1 wheeling?

Mine does the same. Slowly its getting much worse.

Some times it is fine, I can launch with a 4200rpm and only have the wheels chirp all the way through first. Other times it will start then all of a sudden let go.

If give it a little stick on come on to boost in first while turning left, the inside left wheel will spin up and feel very gay as the car doesn't accelerate, doesn't go sideways the slightest & makes lots of noise.

The car's diff 2 years ago used to be really tight. Always sideways never open wheeled on hard cornering etc. But that was 60,000+ km's ago..

[Duncan]

Mine's got stock shocks and lowered springs, and the diff made a huge difference.

For me tho, its not about drifting around the local round about, I'm looking for traction out of corners, and the diff is great there. You can get on the gas far earlier than with my old, worn out stock diff

[Cubes]

Yer wheel spin becomes very annoying. I'd much prefer traction.

Duncan, so you are using what diff?

[Duncan]

Mines a 1 way mechanical, and I'm very happy with it, cost me $500.

Still wondering about benefits of 2 way dif, I take the point that it may be better for drift but surely thats only a small difference (after all you are acellerating - or trying - when you are drifiting...) Any other benefits?

[lwells]

Ducan: Well from what SK was saying in the other thread, if anything a 2way is a disadvantage. Seems like 1.5 is optimal for street/track use.

LW.

[SLY33]

enrico, if the back end steps out, that usually means you are getting drive to BOTH wheels, but in a stock lsd like yours, you may be getting uneven power distribution, eg 70% power to your left wheel and 30%power to the right, and so it steps out just a little. So you may be openwheeling a bit. If both spin together as in a locker, you can feel the back end very consistent, and it will feel a little "floaty" as both wheels have broken traction.