996/997 GT3 Diff Rebuild: Anyone Done it?
Discussion
Hi Folks,
It seems fairly clear now that the diff plates on these cars are made from chocolate; finest 70% coco variety I'm sure, but chocolate all the same. The method to test for a worn out diff appears to be inconclusive, but despite this, I am concerned that there's little or no assistance from my diff when coming out of light speed. I'm still getting lockup out of the corners, but the diff is far from aggressive in any way and the car is very nervous under hard braking (despite a recent geo set-up at JAZ).
Conclusion: the diff's f
ked.
Now, where do I get it sorted (I'm London based)? Anyone got experience of this? The car's still under warranty (although my friendly OPC has since drawn a blank on any notion of an FoC rebuild), so on that basis, I'd rather have the standard LSD rebuilt with stronger internals than do anything too drastic.
I've heard that the 'Cup' internals are the way to go? Thoughts?
It seems fairly clear now that the diff plates on these cars are made from chocolate; finest 70% coco variety I'm sure, but chocolate all the same. The method to test for a worn out diff appears to be inconclusive, but despite this, I am concerned that there's little or no assistance from my diff when coming out of light speed. I'm still getting lockup out of the corners, but the diff is far from aggressive in any way and the car is very nervous under hard braking (despite a recent geo set-up at JAZ).
Conclusion: the diff's f
ked.Now, where do I get it sorted (I'm London based)? Anyone got experience of this? The car's still under warranty (although my friendly OPC has since drawn a blank on any notion of an FoC rebuild), so on that basis, I'd rather have the standard LSD rebuilt with stronger internals than do anything too drastic.
I've heard that the 'Cup' internals are the way to go? Thoughts?
If it's under Porsche warranty then its down to them to sort it out - but it'd be nice if you could just pay the cost different to change to the Motorsport part. I believe the part cost is similar but it requires a little more time & skill to set up correctly - but it is indeed much better quality.
sleep envy said:
thegoose said:
If it's under Porsche warranty then its down to them to sort it out.
To replace a consumable part?Edited by GentlePersuasion on Tuesday 12th February 12:23
Pretty much everyone with a non garage queen milaged GT3 should have had diff rebuilds. It's nothing to be concerned about. As you are aware, the street plates aren't very robust and track driving will finish them off in short order. Just use some of the Cup discs instead of the regular street ones when you rebuild. Fwiw the Cup also uses more discs in its diff stack so mostly you don't want it rebuilt actually to Cup spec or else you may wrestle with the diff on the street.
There is an actual test you can do to check, Porsche give the exact values for brakeaway torque so its not anything mystical that's involved to confirm. .
Instability under braking is the first sign of one being worn from the drivers seat however.
Mike at Sports and Classic would get the usual nod but he may be too far up North for you.
There is an actual test you can do to check, Porsche give the exact values for brakeaway torque so its not anything mystical that's involved to confirm. .
Instability under braking is the first sign of one being worn from the drivers seat however.
Mike at Sports and Classic would get the usual nod but he may be too far up North for you.
Rebuild mine myself last year with Guard internals (Guard Transmission).
It's not hard to do, but if you want it done 100% correct you have to take a measurement first to get plates with a perfect fit as the stack height is slightly different for each differential. I recommend you check out the LSD Buster thread on 6speedonline and/or contact Matt at Guards to get all the info you need for this.
It's not hard to do, but if you want it done 100% correct you have to take a measurement first to get plates with a perfect fit as the stack height is slightly different for each differential. I recommend you check out the LSD Buster thread on 6speedonline and/or contact Matt at Guards to get all the info you need for this.
gt3nor said:
Rebuild mine myself last year with Guard internals (Guard Transmission).
It's not hard to do, but if you want it done 100% correct you have to take a measurement first to get plates with a perfect fit as the stack height is slightly different for each differential. I recommend you check out the LSD Buster thread on 6speedonline and/or contact Matt at Guards to get all the info you need for this.
Thanks,It's not hard to do, but if you want it done 100% correct you have to take a measurement first to get plates with a perfect fit as the stack height is slightly different for each differential. I recommend you check out the LSD Buster thread on 6speedonline and/or contact Matt at Guards to get all the info you need for this.
I've read about the Guard diff. Any idea on prices vs the Porsche Motorsport stuff?
I paid US$1123,- including overseas shipping for all parts needed from Guards. Don't know the exact price on the Cup parts, but I think they cost more.
Note that you have to measure the ramps inside the diff before you order to get plates that are the correct size, as far I understand Guard is the only company that will send you internals that are correct for your ramp size - they are not all the same. You either have to leave the diff out while waiting on the new internals, or you have to do the job twice - but it will be correct doing it this way.
Note that you have to measure the ramps inside the diff before you order to get plates that are the correct size, as far I understand Guard is the only company that will send you internals that are correct for your ramp size - they are not all the same. You either have to leave the diff out while waiting on the new internals, or you have to do the job twice - but it will be correct doing it this way.
From your post in the other thread (for others reading)
Whether or not you feel it is enough is a whole other deal.
GentlePersuasion said:
Not any more than they'd do the clutch (on the premise that Porsche considers the diff to be 'in spec' at >8 lbs torque) which to a normal human being, more often than not means it's fked.
Not that I'm bitter, you understand.
That is the specification for the stock diff. With it removed and one end held in a vice the other side should provide a torque figure of between 5-15Nm (3.5 - 11lb ft). If it achieves this your diff is working as intended. ked.Not that I'm bitter, you understand.
Whether or not you feel it is enough is a whole other deal.
Dave 321 said:
Cup plates are a great upgrade, first did mine in 2009.
But as they are a race part and not road your gear oil needs much more regular changes. There is a coating on the plates that contaminates the oil.
I change mine every 5k miles
I've not heard of this before, where did you get your information from?But as they are a race part and not road your gear oil needs much more regular changes. There is a coating on the plates that contaminates the oil.
I change mine every 5k miles
Cunno said:
I've not heard of this before, where did you get your information from?
Experienced the oil contamination by just changing the oil & put it on another forum.Well respected porsche specialist with a lot of Porsche racecar experience commented saying about the coating on the plates contaminates the oil
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