[30ONA]

I've seen threads where people specially modify the front and rear diffs as there is no bolt on option do for GVs, but can you get or make a center locking diff like on a lot of Toyota? How would this compare of road to only a locked rear. The Toyota I've seen with a center lock seem extremely capable.

[Gwagensteve]

Your vehicle is part time 4wd. That means when 4wd is engaged both front and rear axles receive the same drive- there is no differential to lock. As such, 4wd can only be used on low-traction surfaces like dirt because when you corner the different distance covered by the front and rear axles can be dispersed as slip.

Vehicles with a centre differential are constant 4wd - hard surfaces are no problem. However, on low traction surfaces the centre diff will direct drive to the axle with the least traction, so a lock is provided. This just makes a constant 4wd car the same as your GV once engaged- drive is equally distributed to each axle.

Hope that makes sense b

[30ONA]

That makes sense thanks.

So I guess my friends land cruiser out wheeling me in the sand is probably more to do with the larger geometry of his car (mainly wheels) and nothing to do with a center locking diff.

[henno]

It's probably more to do with clearance and/or the lack of body armour under the GV. The front crossmember of the GV is like a snow plow and is horrible in deep-ish ruts.

With slightly bigger rubber (for more clearance) and a bash plate (to skid rather than dig) my shorty GV was an absolute weapon on the softest of sand.

Conversely, my 100 Series Landcruiser (with 'larger geometry') just plain sucks in comparison.

[watermouse]

To a large extent: Power to ground pressure ratio.
If you can substantially increase your tyre footprint on the sand by reducing tyre pressure, (easier with a less stiff tyre, and lengthways more than sidewall bulge) you will quickly find extra performance in sand driving.
You will hear 18-20psi as recommended pressure in sand driving literature but in my experience for Suzuki 10psi or less.
On a recent club trip I had a newcomers sierra, on super stiff Buckshots, down to 5psi before we were getting the performance I expected of a light car in soft sand. It was only then he could keep up with the big guys with 200+kw

[30ONA]

Found this awesome link.

http://www.lcool.org/technical/diffs/diffs.html

So on a GV with rear solid axle and front independent, if you could only lock one, diff would you choose? My understanding was that the solid axles are less likely to hang up and spin as independent. If this is correct and you only have the option to lock one diff you would lock the front?

[Gwagensteve]

Always the rear first.

Front end is weaker, asking the front to drag the rest of the car up an obstacle is hard on the driveline. Additionally, you most need a locker when climbing. It makes sense to lock the axle that has the most traction- which is the rear, because that's where the weight transfers. (Weight=traction)

Steering is also impeded with the front locker engaged.

[30ONA]

Gwagensteve wrote:

Always the rear first.

Front end is weaker, asking the front to drag the rest of the car up an obstacle is hard on the driveline. Additionally, you most need a locker when climbing. It makes sense to lock the axle that has the most traction- which is the rear, because that's where the weight transfers. (Weight=traction)

Steering is also impeded with the front locker engaged.

Thanks.

[ZUZUKI]

ARB Air Locker diffs are available for this car - about $1100 each end, plus air compressor $200, plus installation = around $2000 for for the rear & $3500 to do both (need to change the L/H/F driveshaft for one out of a late Vitara).

I'd find some traction from more suitable tyres before looking at locking the diffs, but if you have money to burn, go for it. Flat, soft beach sort of sand is where cross axle diff locks are probably at there least useful. Climbing lumpy sandy hill are a different matter, but on flat sand, I run out of clearance before I run out of traction that would be helped by my diff locks.

Also in relation to the front cross member, it will be hitting the 'crown' of deepish sand tracks & throwing sand all over the place in the engine bay. The engine is not particularly well sealed from sand, so a skid plate is highly recommended, otherwise the bellhousing can fill with sand & you'll shortly have front & rear crank seal leaks.

The other big tip with a GV (I assume that it is a 2.5litre V6?), is to keep the boot into it - the fuel consumption will be horrendous (like 20+l/100 km, but you really need to be around 3500rpm in soft stuff, to minimize the engine 'bogging down' & allowing for a quick down change if it does start to bog down - I don't mean the car sinking, but rather the engine falling off it's torque curve and labouring - it's always going to be hard work in sand below 2500rpm.

Good luck with it.
Rgs, Michael

[30ONA]

ZUZUKI wrote:

ARB Air Locker diffs are available for this car - about $1100 each end, plus air compressor $200, plus installation = around $2000 for for the rear & $3500 to do both (need to change the L/H/F driveshaft for one out of a late Vitara).

I'd find some traction from more suitable tyres before looking at locking the diffs, but if you have money to burn, go for it. Flat, soft beach sort of sand is where cross axle diff locks are probably at there least useful. Climbing lumpy sandy hill are a different matter, but on flat sand, I run out of clearance before I run out of traction that would be helped by my diff locks.

Also in relation to the front cross member, it will be hitting the 'crown' of deepish sand tracks & throwing sand all over the place in the engine bay. The engine is not particularly well sealed from sand, so a skid plate is highly recommended, otherwise the bellhousing can fill with sand & you'll shortly have front & rear crank seal leaks.

The other big tip with a GV (I assume that it is a 2.5litre V6?), is to keep the boot into it - the fuel consumption will be horrendous (like 20+l/100 km, but you really need to be around 3500rpm in soft stuff, to minimize the engine 'bogging down' & allowing for a quick down change if it does start to bog down - I don't mean the car sinking, but rather the engine falling off it's torque curve and labouring - it's always going to be hard work in sand below 2500rpm.

Good luck with it.
Rgs, Michael

For $2K I'LL STICK WITH A SNATCH strap and wheeling buddy.

Mine is 2L 4cyl, I find on flat in sand it needs to be sitting on our about 3k. I also have a front sump guard. Planning on getting at grabbers when my highway tyres run out if tread.

[Gwagensteve]

You'd only say that if you haven't driven a car with a rear locker. Quite literally, the performance increase between open diffs and a rear locker is similar to the difference between 2wd and 4wd.

It's THAT significant.

The difference a second (front) locker makes is much smaller. Still significant, but smaller.

[alien]

^^ what he said.

Air lockers are brilliant. Open diffs on the road so it behaves like a normal, and selectable offroad - so you can drive the entry tracks in 2wd high, then if it's getting a bit rutty but still lots of traction you can bung on the locker and keep on going without having to touch 4wd. Then when it gets really tough in 4wd, those lockers save you having to even think about recovery gear.

Now, that said - lockers do get you further than you'd have gotten without them, which also means you get get further into a boggy bit, or further up a shoddy cross-slope before getting stuck anyway and needing a more involved recovery than if you'd gotten stuck 10-20m earlier unlocked =)

[Gwagensteve]

I'm not sure if your experience relates to sand, but that's not how I use a selectable locker at all.

In don't use 4H at all and wouldn't lock a diff in 4H or 2wd.
I drive the car open diffed until I anticipate a locker is required and then lock the car to clear the obstacle.

Happy to agree that sand is a completely different ball game.

Although my current car is spooled rear, airlocker front, my use of the front locker follows the same practice.

[alien]

I've used 2wd rear locked on fast gravel sections in order to utilise the oversteer. Likewise as I said on entry tracks, on the fly just hitting the button to pop over a rut that you're going to lose traction on rather than hoping 4wd will give that traction and not just spin front and rear. Basically i'm using the locker before i lose traction and rip up the track spinning my wheels, unless spinning my wheels (with the locker on) is the goal =)

I use mine the same as you when i'm "actually wheeling" - Open diffs up until an obstacle, assess, lock rear or front & rear depending on what line i'm going to take, and re-open diffs to move to the next section.

I have VERY limited experience on sand with my current setup, however i have found that rear locked works best on sand. Front locked doesn't seem to be as useful due to the way it impacts steering.

[Gwagensteve]

I agree that sand is a perculiar challenge for locked diffs. In turns the relative speed difference makes the inside wheel dig at low speed, which is pretty inefficient.

[alien]

But inversely, in a straight line, the locker tends to help the wheels float by not allowing just 1 wheel to dig =)

[Gwagensteve]

Yeah agreed.

Most of my sand experience has been with heavy/big cars where the effect of turns when locked is very obvious.

I agree that driving locked rear on fast dirt is appealing. My cars with selectable rear lockers haven't been the sort of car you'd drive that out of shape. Piggles is quite good fun with a spooled rear on fast dirt through.

I'm not sure I'd drive a GV in 2H with the rear locked for bulk oversteer though.

[henno]

Gwagensteve wrote:

I'm not sure I'd drive a GV in 2H with the rear locked for bulk oversteer though.

Hell. No.

The GV by design (in my experience, at least) seems to tend towards bulk understeer into snap oversteer already; the last thing I'd want is to exacerbate the rear end trying to drive around the front.

[Gwagensteve]

I wonder if that's a legacy of the positive roll axis inclination problem vitaras share. At least with a vitara though, suspension lift helps to flatten it out because of the rear a frame. (Which fixes roll centre irrespective of lift). For the GV rear roll centre will rise with lift, perhaps meaning the problem isn't lessened with lift as it is in a vitara.

Interesting.

[alien]

Well, that's what happens when manufacturers consider your car in the same range as a household appliance versus a driving machine. It can play cat videos off the internet and keep your ass warm, but ask it to turn a corner at speed and it might try to kill you =)

The head of VW in the USA quoted the other day:

“That's an acknowledgement of the shifting priorities of younger car buyers. They are less infatuated with driving thrills like taking tight turns and more excited about features like seamless smartphone integration embodied through a system VW”

Pitiful.

[30ONA]

I'm not saying I would get a locker, but that I can't afford one.

[Gwagensteve]

Sure, there are other, cheaper alternatives though to an air locker.

[30ONA]

Auto lockers seem ok performance wise but they click the whole time. Kind of like a mechanical lsd from what I understand.

[alien]

bang for buck offroad performance increase without affecting on-road in any way, airlockers are the #1 solution.

Save your pennies =)

[Zook_Fan]

henno wrote:

Gwagensteve wrote:

I'm not sure I'd drive a GV in 2H with the rear locked for bulk oversteer though.

Hell. No.

The GV by design (in my experience, at least) seems to tend towards bulk understeer into snap oversteer already; the last thing I'd want is to exacerbate the rear end trying to drive around the front.

I got the exact same as that running in 4H at speed with a spooled rear end. If I was driving a GV on the road I don't think I'd want any diff locking mechanism I couldn't unlock.

[30ONA]

On an air locker, when you engage it the compressor turns on to activate, does the compressor need to hold the pressure to keep the diff engaged? I.e. is the compressor running the whole time you have the locks on?I would imagine a good system would have no leaks so it hold pressure after a short burst from the compressor then a solenoid would release the air when you turn off?
I'm thinking about fitting a compressor for camping and 4wding but also having the option of a locker later. Does it matter if I mount under the bonnet, making an air line to the rear longer?

[fordem]

No the compressor does not run for the entire time the lockers are engaged, and you can mount the compressor where ever you choose, the length of the line does not matter.

Out of curiosity, why would you need a compressor for camping?

[Zook_Fan]

The compressor does not run but it is turned on. If it is turned off the locker solenoid will release unless you modify the wiring.

The compressor kicks in for a short burst as you said and a good system won't leak much at all but the compressor will more than likely kick back in eventually for a few seconds unless you have you system really sorted.

[30ONA]

fordem wrote:

Out of curiosity, why would you need a compressor for camping?

Pumping up tyres after deflating and to pump up my jumping castle.

[Gwagensteve]

I hope you're camping for a while because even an air bed takes forever to air up with a compressor suitable for tyres. Tyres need pressure. Toys need volume. Different tools for different jobs.