Don't do handbrake turns in your AWD Subie

Ratbag

Ratbag

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Joined
Jan 1, 2012
Messages
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Location
Bayside, Melbourne, Vic
Car Year
MY06, MY10
Car Model
Forester SG & SH
Transmission
5MT/DR & 4EAT Sports
Gidday Folks

Last week I had the chance to inspect a centre diff after the owners had been doing handbrake turns in their car. The damage is not a pretty sight!

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Probably a good manoeuvre to avoid, by the look of this ... :puke: :puke:.
 
^ I don't think it would.

Driving a car usually involves all four wheels going in the same direction, albeit sometimes at very different speeds.

During a handbrake turn under power, wheels can possibly be turning in different directions. This would place enormous strain on any LSD, whether viscous or mechanical.

A two wheel drive car differential may be capable of withstanding this, however the centre diff in a constant AWD car is not designed to cope with this kind of strain. Basically the equivalent of axle wind up in a conventional 4WD vehicle with no centre diff.

The result is pretty horrible damage, in either case.

When I accidentally left my LC in 4WD when I pulled out of a dirt road onto a bitumen road, one of the front drive shaft universal joints tore itself apart within about 50-100 metres.

That universal joint was quite capable of withstanding the forces put on it in normal use with a ton in the back and towing a 2 ton horse float. It could not withstand the forces put on it by simple axle wind up caused by being used on a bitumen road.
 
Yep, every Subie owner needs to know never to do a handbrake turn, no matter how much fun lol.

However this only applies to a manual using a viscous LSD. Not sure how the auto handles it with its different centre.

Those lucky enough to have a DCCD can safely do handbrake turns if they've wired in the handbrake to the controller (Venom!!! :lildevil: ). A welcome side effect of Subarus rally development :)
 
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Well last winter I would of done atleast 30x hand brackies. No issues as of yet and fun factor was high.
I have 2x spare centre diffs, one being a 20kg so I'm prepared.
 
I did 1 today and must have done at least 20 in total but never under acceleration.

Feint, braking drift and lift off oversteer will pretty much cover any situation you might be tempted to handbrake except the tightest of turns.
 
It doesnt matter if you're accelerating, its to do with the front wheels turning fast & the rears suddenly locked up with the centre diff connecting the two.

There are people who complain they dont get drive to the rear wheels when they're going up a steep hill or dune. Thats what happens when you bugger the centre diff, it becomes like an open diff.

I seriously recommend if you have a manual with a viscous centre diff, dont use the handbrake while moving. That is if you want it to keep working lol :poke:
 
and to play it safe with an auto, insert the "FWD" fuse then go play ;-) Never tried it but should give excellent hand brake turns (only on private property of course!).
 
Aw :-( that would explain why my mechanic said my diff was destroyed :-(
 
^ That's why I started the thread, Twink.

Too late for you, but might help others avoid the same fate.

Sorry to hear about your diff ... :(.
 
What ur centre diff twinkles?

Sure its not ur rear. That is real common to go...

My front diff is making a grinding noise under load but I believe the back lash needs adjusting..
 
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Uh, well, apparently all my diffs ( there's three right?) and my gearbox are absolutely dead, quite dramatically so. So I'm upgrading to a custom made gearbox and top of the line LSD'S :-D
 
^ Yup, three's the magic number.

In your model, front and rear are open diffs, and the centre is a viscous LSD.

In the later (MT) models, the front is an open diff, the rear and centre diffs are vLSD.

Nothing wrong with vLSDs, just don't ill treat them. I suppose that goes for almost everything ... :iconwink:
 
It shall be interesting driving the Twinkmobile after it has been rebuilt!
 
^ After the rebuild, it will be even more important not to do handbrake turns. vLSDs have a lot more 'give' in them than mechanical LSDs. They will crap out, but they won't generally break into hundreds of un-numbered pieces ...
 
If I do the rebuild correctly I'll have more fun in the mud and won't want to to handbrake turns!
 
^ Mud. Mud??

Where the heck are you going to find MUD in WA??

If you have a secret stash, you could make a bundle renting it out to Taza ... :biggrin: :rotfl:.
 
Haha, there's plenty around, I just ask the mud caked patrols that come into work o_O
 
Mud is ****. Just look at what happened to your car on one of the previous trips twink.

Wet weather = good old fashion aussie spirit.... in other words drift action.

That gearbox sounds expensive twink. Better make sure you got heaps of cash.
What mods you doing to it? Who is building it? In WA or over east? What type of diffs..? Helical, clutch or torsion? What centre? Dual syncros or taller 5th?
You going to change the main shaft with one that's got a stronger reverse?


How did you manage to f*** all 3 diffs? What exactly is wrong with them? You sure its not just one diff. Even guys with over 300whp dont bust all 3 diffs at once.
Is one whining? Broken teeth?
 
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