Convert C 4 box to C2
10-11-2017, 04:17 AM
#125
Burning Brakes
one remark to the show functionality of the PDAS as differential lock.
How is the status of the friction discs? I guess, this discs wear out during the time?! Perhaps, a gearbox overhaul with refreshing the friction plates (from valeo if i am right) could help here?!
Very interessting experiences, you`re gaining here...
How is the status of the friction discs? I guess, this discs wear out during the time?! Perhaps, a gearbox overhaul with refreshing the friction plates (from valeo if i am right) could help here?!
Very interessting experiences, you`re gaining here...
10-11-2017, 04:33 AM
#126
Rennlist Member
Originally Posted by koenig_roland
one remark to the show functionality of the PDAS as differential lock.
How is the status of the friction discs? I guess, this discs wear out during the time?! Perhaps, a gearbox overhaul with refreshing the friction plates (from valeo if i am right) could help here?!
Very interessting experiences, you`re gaining here...
How is the status of the friction discs? I guess, this discs wear out during the time?! Perhaps, a gearbox overhaul with refreshing the friction plates (from valeo if i am right) could help here?!
Very interessting experiences, you`re gaining here...
10-11-2017, 10:19 AM
#127
Burning Brakes
I would be tempted to forget the rear diff altogether tbh. First it doesn't lock on deceleration which is the main bonus of a LSD on a 911 and second it could well be the PDAS system is constantly trying to lock/releas the rear diff which could be the cause of the drive shaft failure?
10-11-2017, 01:01 PM
#130
Burning Brakes
When the diff locks it gives the car much better stability under heavy breaking as the two rear wheels are rotating at the same speed.
PDAS works only on acceration and not deceleration hence my comment that the diff isn't locked.
PDAS works only on acceration and not deceleration hence my comment that the diff isn't locked.
10-12-2017, 09:48 AM
#131
Instructor
Ok, thanks.
I think it's for the same reason that the ABS at the rear works together left and right, i.e. if on the rear right is releasing brake pressure the same input is given also to the left.
I think it's for the same reason that the ABS at the rear works together left and right, i.e. if on the rear right is releasing brake pressure the same input is given also to the left.
10-12-2017, 01:58 PM
#132
Burning Brakes
The aim of the ABS is a little different to the diff. The 964 has 3 channel ABS with only one solenoid controlling the two rear brakes. If it senses one of the rears lock (a bad scenario in any 911) then it will release pressure to both rear brake calipers. This offers more stablity but nothing like the stability as a locking diff.
The later 4 channel ABS systems can release the rear calipers individually to achieve optimal braking.
The later 4 channel ABS systems can release the rear calipers individually to achieve optimal braking.
11-20-2017, 08:55 AM
#133
Three Wheelin'
Well all still up in air with my car. just replaced the broken CV joint but not upgraded as yet as it turns out that the C4 diff will not work with the flanges used with the C2 shafts. Also everyone I have spoken to has a different theory as to why it broke. The fact that the PDAS engages the diff constantly has been discounted by checking with a PWIZ diagnostic. Shows all working well and diff engaging and disengaging at the right times.
Gearbox twist on the original C4 gearbox mount was also muted but i have to say that with the RS Engine mounts I have in place I really can get much movement out of the box, plus it would need to be quite severe movement to exceed the range of the CV joint. So don't think this is the issue.
The guys looking at it with me currently, RSR here in the UK, think it is more than possible that it was already fatigued after 120,000 miles. These size of shaft and CV joint is the same as used on the 944 turbo so in theory it should be ok with about 250hp at least.. my car should have maybe 30 more than that but still you would just expect quicker wear rather than an immediate break.
Anyhow have a track day booked for 1st December but very weary about going with the 964 in case it breaks again, the issue is more the pain of having to pay to get it recovered and taken home. So not sure how i will proceed at this point. i think ultimately it will come down to C2 shafts and a mechanical LSD. Both items wghiuch would have been need if using a C2 box in any case.
11-22-2017, 11:45 AM
#134
Burning Brakes
The C4 shafts are also the same ones that are used in 204 HP Boxsters...
I had also a driveshaft failure this year... well. Replaced it an proceed trackday driving...
I had also a driveshaft failure this year... well. Replaced it an proceed trackday driving...
12-06-2017, 07:30 AM
#135
Three Wheelin'
Update on my C2 conversion using the C4 box - this time it was a success!!
Still using C4 shafts because using C2' would mean changing the diff.. the flanges on the PDAS C4 diff are unequal lengths. Also wanted to see if the PDAS was working or not.
One unexpected outcome, despite the fact that the diff does not work when car is off throttle.. is that the braking felt more composed than when it was a C4.. i think having engine braking only on the rear wheels helps with stability?
Still using C4 shafts because using C2' would mean changing the diff.. the flanges on the PDAS C4 diff are unequal lengths. Also wanted to see if the PDAS was working or not.
One unexpected outcome, despite the fact that the diff does not work when car is off throttle.. is that the braking felt more composed than when it was a C4.. i think having engine braking only on the rear wheels helps with stability?