someone school me on lsd please.

[barely legal]

im looking at lsds for my v6 vr wagon. its a street car only.
i know at this stage i don't want a mini spool or a full spool.
i will be driving the car for work and it will be during all seasons. so i don't want to crash my car in the wet just cause i've gone the tightarse option.

so here is where i need help.
correct me if i'm wrong, but i know there is.
Open Centre Diff: spins both wheels until uneven resistance is placed on the wheels, then it will transfer all power to the wheel with the least amount of resistance.
or single spinner?

LSD Centre Diff: spins both wheels but uses a clutch to allow the wheels to move at different speeds if required, ie turning a corner.

and then there is your spools.

what i want to know is what different ratios mean?
whether lsd means both wheels constantly moving.. more or less.
and lastly. can anyone give me a contact for a good diff shop in the s/e suburbs victoria or mornington peninsula area.

thanks. i'm a bit of a noob when it comes to diffs.
but thanks.

[VN_Luke]

Hey mate, you've got it pretty much spot on!

in reality, it's very rare to get even resistance accross both wheels in a single spinner car - meaning that if you hit a slippery surface, you'll be putting your drive towards whichever wheel breaks traction first.

The different ratios are the ratio of turns of the tailshaft:turns of the wheels

i.e. a ratio of 3.08 means that for every 3.08 turns of the tailshaft, the wheels will turn one full revolution.

a ration of 3.45 means that every time the tailshaft turns 3.45 times, the wheels turn one full revolution. (so in this example, the tailshaft (hence engine) needs more revs to drive the wheels at the same speed.)

an LSD will try put equal drive to both rear wheels - essentially (in a simplified way) - it's using clutches to affix the axles to the diff center... so the whole lot is trying to spin as one. - something needs to happen to overpower the clutches (or cones as is the case in the BW lsd), such as a corner, and this allows the wheels to turn at different speeds.

I recommend Steve at Ash Differentials in Carnegie (you can find their contact details on whitepages.com.au) - always been good to me, and great prices.

Rear 363 Neerim Rd Carnegie Phone/Fax 3163
(03) 9569 4846


Be advised that if you're planning to do bulk burnouts - the LSD will not last. It is possible to extend the longetivity of the diff via machining of the cones, and replacement/upgrading of the springs.

for a spaz amount of information on diffs and how they work, check out:

How Differentials Work

good luck and happy diffing.

[barely legal]

are you saying you want a lower ratio?
this is what i struggle to fathom.

EDIT: i read the "how stuff works" and now get that.
"the input pinion is a smaller gear than the ring gear; this is the last gear reduction in the car. You may have heard terms like rear axle ratio or final drive ratio. These refer to the gear ratio in the differential. If the final drive ratio is 4.10, then the ring gear has 4.10 times as many teeth as the input pinion gear."

all that is left to ask is. is it better to go for lower or higher ratios?
and why?

[Clutchy]

are you saying you want a lower ratio?
this is what i struggle to fathom.

EDIT: i read the "how stuff works" and now get that.
"the input pinion is a smaller gear than the ring gear; this is the last gear reduction in the car. You may have heard terms like rear axle ratio or final drive ratio. These refer to the gear ratio in the differential. If the final drive ratio is 4.10, then the ring gear has 4.10 times as many teeth as the input pinion gear."

all that is left to ask is. is it better to go for lower or higher ratios?
and why?

Final drive comes down to a few things.
As for your ratio chice what do you want from your car were is the bulk of your driving going to be done ? and how many revs you want it doing on the highway if ya will be driving it on the highway.

[barely legal]

Final drive comes down to a few things.
As for your ratio chice what do you want from your car were is the bulk of your driving going to be done ? and how many revs you want it doing on the highway if ya will be driving it on the highway.

a fair bit of the driving will be at 80/100 k's but then again alot of it will be built up area driving.

[feistl]

I'm hoping this is helpful,

say you run a "lower" (not sure if thats the right word) ratio like 3.08 that means you might be doing 1400rpm/100kph (random guess here). Now that might be fine for a V8 (lots of torque), but with a "weaker/lower power" engine it might struggle. Bad vibrations etc (imagine driving everywhere in top gear). No acceleration etc, i think its also bad for the engine/gearbox etc but i could be wrong.

Say you run a higher ratio like 4.11 it could mean your doing 2500rpm/100kph (again, pulling numbers out of my arse). The advantage is its easier on the engine, more response, better acceleration etc. The downside is your reving a lot higher, which means more fuel (usually) and more wear and tear.

Normally with a higher ratio (4.11) you'll be changing gears more, as you run out of revs quickly. Whereas a lower ratio (3.08) means longer speed ranges per gear.

3.08 diff, 1st gear = 0-50kph.
4.11 diff, 1st gear = 0-30kph.

It will also effect your top speed (although this shouldn't be an issue for normal driving).

So in summary, you basically want a diff to suit your engine type/power. A powerful V8 can handle a low ratio diff (3.08) as it has a lot of bottom end torque.

Whereas a 4 cylinder 1.3L will require a much higher ratio so its spinner faster all the time (to produce as much power as possible).

Just as a side note, diesel engines normally produce a lot more torque and therefore can handle lower ratios, whereas petrol engines need higher revs to get the same power.

My VR V6 (manual) runs at about 1800rpm/100kph, which basically idles along nicely. Doesnt use much fuel, although has no "get up and go" at that speed/gear.

Personally, for around town id get a higher ratio diff (better acceleration, response). For long highway driving/high speed id consider a lower ratio diff (better fuel economy, less engine revs).

Hope this helped (and i got it all correct :P). If not, please dont flame me

Cheers

EDIT - It also depends on your gearbox... Manual could probably get away with a higher ratio as there are more gears (5 or 6 compared to 4 for an auto). Means you'd be changing gear more but plenty of power. Auto's may struggle with a higher ratio as they would have to constantly rev out/high to accommodate the higher ratio.

[barely legal]

that helps.
so i'm basically going to have to chat to the guy who's doing my lsd.
and go for something in the middle.
so as not to compromise too much response and acceleration. but also to not have my car drinking petrol.

[STEALTHY™]

im looking at lsds for my v6 vr wagon. its a street car only.
i know at this stage i don't want a mini spool or a full spool.
i will be driving the car for work and it will be during all seasons. so i don't want to crash my car in the wet just cause i've gone the tightarse option.

You've been severly misinformed about spools. Anyone with half a clue how to drive has no problems.

And keep in mind, an LSD has the same locking effect, the only difference is when your cornering, so you had better learn to drive, even if you get an LSD.

[Jesterarts]

One the minispool and fullspool... illegal... plus touchy touchy around corners...

Why would you PAY for something that reduces you cars corner handling...lol

On the "ratio" note... PERSONALLY... i got a 3.73 put in my VX 6 and i was happy with that... good up and go and not TOO much fuel lost.

GOod Luck

[STEALTHY™]

Why would you PAY for something that reduces you cars corner handling...lol

People pay for LSDs all the time, whats your point?

[barely legal]

One the minispool and fullspool... illegal... plus touchy touchy around corners...

Why would you PAY for something that reduces you cars corner handling...lol

On the "ratio" note... PERSONALLY... i got a 3.73 put in my VX 6 and i was happy with that... good up and go and not TOO much fuel lost.

GOod Luck

was that auto or manual.
what price did it end up being?
thanks