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Discussion Starter #1
Hi all,

I have been wondering about this for awhile now. If I lock the rear wheels with the parking brake while the car is moving, what is happening in the center diff? Will the clutches eventually fry?

Note: I am only assuming there is some center diff so the AWD can function on dry pavement.

Thanks,
Cole
’05 TX PP manual
 

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Mr. April 2008, Image Master
2005 X
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So long as the vehicle is out of gear or your foot is on the clutch you can use the e-brake to your hearts content. Or at least that's my understanding of it...
 
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Discussion Starter #3
Could I also do that in an automatic as well, like rip the e brake while I'm in neutral???
 

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I imagine you could damage something if the brake was applied continously. I sometimes use the e/hand brake to retard the car on steep stuff by lightly applying, just a couple of clicks, for short periods of time.
 

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Recovering Modaholic
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I beleive its deadly for the center diff IIRC. if you want the rear to slide out on pavement, get a fatter RSB and pump up the rear tire pressure to about 42 psi and keep the fronts at 32psi.
 

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Yep, could cause damage, especially on an Automatic. If you really want to use this feature, and you have an auto, you could design a switch to disengage the electronic transfer clutch (no diff on Autos). I believe the STI with DCCD disables the center LSD when e-brake is engaged. Maybe other Subarus with DCCD or automatic transmissions do the same? Manuals use a mechanical viscous coupling and a true differential, so no way to desengage it.
 

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The Wraith said:
So long as the vehicle is out of gear or your foot is on the clutch you can use the e-brake to your hearts content. Or at least that's my understanding of it...
Can anyone else confirm this?

DOHCammin said:
pump up the rear tire pressure to about 42 psi and keep the fronts at 32psi.
Will that 10PSI difference affect the AWD because the rear diameter might be too big compared to the fronts?
 

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Mr. April 2008, Image Master
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Will that 10PSI difference affect the AWD because the rear diameter might be too big compared to the fronts?
Nope, not a prob.
 

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Do you know how much of a Rear to Front bias you'll need to start messing up the AWD drivetrain due to conflicting rolling diameters?
 

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Mr. April 2008, Image Master
2005 X
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jbleee said:
Do you know how much of a Rear to Front bias you'll need to start messing up the AWD drivetrain due to conflicting rolling diameters?
I have no idea. Though I have run as much as 14psi dif ft & rr before, and can safely say it was no fun... 38ft & 42rr is what I have mine at right now. Makes the rear a bit tail happy but that's the point. :evil:
 

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The Wraith said:
I have no idea. Though I have run as much as 14psi dif ft & rr before, and can safely say it was no fun... 38ft & 42rr is what I have mine at right now. Makes the rear a bit tail happy but that's the point. :evil:
agreed, I ran a 10psi difference for autoX and it worked great...probably not a good idea for daily driving. It was very easy to get the rear to slide, even with RE0-70's
 

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DOHCammin-
Back in the Old Ages, before pavement going AWD and FrontWD vehicles, the way to get oversteer was to set your front tire pressures to factory reccomended maximum, and lower your rear tire pressures progressively to get more and more oversteer. 10 pounds was usually more than enough, in fact, you couldn't compete with 10 pound less than factory recommended tire pressures, as you ran the risk of de-beading your tires while cornering.
While I never knew anyone who wanted to induce more understeer on American built cars "back then" (they had plenty engineered into them), lowering front tire pressures relative to the rears, induce understeer.

The fact that you're able to "induce oversteer" by raising your rear tire pressures by 10 pounds show you how 'upside down' handling gets when you go AWD. It's a VERY difficult engineering feat to make an AWD system perform better than a rear wheel drive system. Notice how much more money is paid for AWD vehicles to improve upon the Honda S2000 (under $40K) and the top line Corvettes (under $60K) g-forces generated in track conditions.
Do we have any modded FXT's or STi's that are kicking S2000 or high dollar Corvette butts?
-Quick
 
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