C4 Diff Lock
Thread Starter
Instructor
Joined: Jul 2011
Posts: 233
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From: Reading, UK
C4 Diff Lock
Can anyone help me with a question regarding the diff lock on my new 964?
When i 'lock' the diif on the car by turning the diff lock switch, am i locking the back from side to side (i.e. now having a lock diif) or locking the front to back, or both?
Also when the diff is in normal position is it a slip diff, or a limited slip diff?
Cheers
Simon
When i 'lock' the diif on the car by turning the diff lock switch, am i locking the back from side to side (i.e. now having a lock diif) or locking the front to back, or both?
Also when the diff is in normal position is it a slip diff, or a limited slip diff?
Cheers
Simon
IHI KING!
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Joined: Aug 2001
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From: Nashua, New Hampshire, USA
When you lock the diffs, you are locking the center (front to back) and the rear diffs. When its in normal position, the computer locks the diffs as it deems necessary using the accelerometers as inputs.
Thread Starter
Instructor
Joined: Jul 2011
Posts: 233
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From: Reading, UK
Another question - if i lock the diifs do they unlock when i chang to a certain gear or reach a certain speed etc?
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Joined: Jun 2010
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From: Detroit (Rock City); 1990 C4
They'll revert to normal behavior above (I believe) 40km/h.
The new secret is that if you hold the lock switch in the 'lock' position for longer than 10s the automatic differential adjustment is deactivated; it won't reactivate until you turn the car off.
Use care.
The new secret is that if you hold the lock switch in the 'lock' position for longer than 10s the automatic differential adjustment is deactivated; it won't reactivate until you turn the car off.
Use care.
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Joined: May 2007
Posts: 2,292
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From: Portland, Oregon
^+1... Not sure if you're new to the 911/964 platform, but I'd get used to the car a bit first before going too far disabling the C4 system. Do it where you have some space like an empty parking lot. The purists will tell you that throttle-off oversteer is awesome, but it's best under controlled circumstances...
I have driven my car for years in the normal C4 mode, and it really never needs manual intervention. I only used the locks once in sand to try it... otherwise when locked the car is the same as a Jeep in 4WD.... all wheels locked together. Otherwise the PDAS system works very well, kicking in when necessary, keeping novices like me out of the weeds.
I have driven my car for years in the normal C4 mode, and it really never needs manual intervention. I only used the locks once in sand to try it... otherwise when locked the car is the same as a Jeep in 4WD.... all wheels locked together. Otherwise the PDAS system works very well, kicking in when necessary, keeping novices like me out of the weeds.
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Joined: Oct 2003
Posts: 1,861
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From: Bay Area, CA
I installed the Green PDAS light in car so I can see when it turns on. I've never driven my car hard enough to see it come on during cornering but do so it come on over bumps sometimes. Looking forward to tracking my car one day to see the PDAS in action.
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Thread Starter
Instructor
Joined: Jul 2011
Posts: 233
Likes: 0
From: Reading, UK
They'll revert to normal behavior above (I believe) 40km/h.
The new secret is that if you hold the lock switch in the 'lock' position for longer than 10s the automatic differential adjustment is deactivated; it won't reactivate until you turn the car off.
Use care.
The new secret is that if you hold the lock switch in the 'lock' position for longer than 10s the automatic differential adjustment is deactivated; it won't reactivate until you turn the car off.
Use care.
I'm new to the 964 and i'm just trying to find out more about it really. I don't necessarily intend to try these things yet. I am doing a session with an advanced instructor in the spring though on a closed track
Cheers
Simon
