928 S2 manual gearbox into an S4
12-15-2018, 05:07 AM
#1
Instructor
Thread Starter
928 S2 manual gearbox into an S4
Does anyone have any experience of converting a euro 928 S4 1987 auto to a manual. All of the manual parts I can get are from an 1983 S2.
i don’t want to buy the stuff if it won’t fit, so I’m hoping someone can tell me, and any other issues I’m likely to encounter? Tia.
i don’t want to buy the stuff if it won’t fit, so I’m hoping someone can tell me, and any other issues I’m likely to encounter? Tia.
12-15-2018, 07:02 AM
#2
Rennlist Member
I can only advise you what I uncovered when investigating such a project and decided it was just not worth the effort for me personally.
As I understand the earlier gearboxes are prone to wear of the synchros so mating with the S4 motor will not improve matters. Other than that I understand grafting such a unit into the S4 is distinctly possible even if it is not desirable compared to the later model gearboxes. If doing such I would also want a LSD diff unit in the transaxle.
Presumably you understand that what you are contemplating is no minor task, it has been done before and you will need to fit the plate that carries the clutch mechanism to the S4 body not to mention the pedal rail, slave cylinder etc etc.
As I understand the earlier gearboxes are prone to wear of the synchros so mating with the S4 motor will not improve matters. Other than that I understand grafting such a unit into the S4 is distinctly possible even if it is not desirable compared to the later model gearboxes. If doing such I would also want a LSD diff unit in the transaxle.
Presumably you understand that what you are contemplating is no minor task, it has been done before and you will need to fit the plate that carries the clutch mechanism to the S4 body not to mention the pedal rail, slave cylinder etc etc.
12-15-2018, 08:11 AM
#3
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Does anyone have any experience of converting a euro 928 S4 1987 auto to a manual. All of the manual parts I can get are from an 1983 S2.
i don’t want to buy the stuff if it won’t fit, so I’m hoping someone can tell me, and any other issues I’m likely to encounter? Tia.
i don’t want to buy the stuff if it won’t fit, so I’m hoping someone can tell me, and any other issues I’m likely to encounter? Tia.
http://www.landsharkoz.com/tech/stu/conversion.htm
12-15-2018, 08:53 AM
#4
Instructor
Thread Starter
Hi Fred, thanks for the quick reply. I’m lucky that my car was specked with an LSD when ordered new, and I agree, is a great combo with the manual.
can you elaborate on the ‘plate that carries the clutch mechanism’ What I am possibly buying is ‘everything’ to convert includes pedals, flywheel, clutch, starter, slave cylinder, torque tube, etc etc. No mention of the plate you refer to though!
It’s a Porsche, in my experience of them, there’s no such thing as a simple task!
can you elaborate on the ‘plate that carries the clutch mechanism’ What I am possibly buying is ‘everything’ to convert includes pedals, flywheel, clutch, starter, slave cylinder, torque tube, etc etc. No mention of the plate you refer to though!
It’s a Porsche, in my experience of them, there’s no such thing as a simple task!
12-15-2018, 09:09 AM
#5
Instructor
Thread Starter
Great info! Thanks. Need to see about the bulkhead plate viability/sourcing. If I can’t locate that plate, do you think I could reinforce the area and fit a motorsport type master cylinder instead?
12-15-2018, 01:27 PM
#6
Rennlist Member
Hi Fred, thanks for the quick reply. I’m lucky that my car was specked with an LSD when ordered new, and I agree, is a great combo with the manual.
can you elaborate on the ‘plate that carries the clutch mechanism’ What I am possibly buying is ‘everything’ to convert includes pedals, flywheel, clutch, starter, slave cylinder, torque tube, etc etc. No mention of the plate you refer to though!
It’s a Porsche, in my experience of them, there’s no such thing as a simple task!
can you elaborate on the ‘plate that carries the clutch mechanism’ What I am possibly buying is ‘everything’ to convert includes pedals, flywheel, clutch, starter, slave cylinder, torque tube, etc etc. No mention of the plate you refer to though!
It’s a Porsche, in my experience of them, there’s no such thing as a simple task!
12-15-2018, 01:38 PM
#7
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The piece of firewall is the mount for the clutch master cylinder which need only be riveted and glued over the new hole you cut in the existing automatic firewall. (yes Porsche had two chassis ) You also need to fit the smaller flywheel to the S-4 crankshaft but need it to be custom so it has the correct trigger wheel for the S-4 timing sensor....... that ring must be correctly indexed and tack welded in place.
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12-15-2018, 04:01 PM
#9
Rennlist Member
The piece of firewall is the mount for the clutch master cylinder which need only be riveted and glued over the new hole you cut in the existing automatic firewall. (yes Porsche had two chassis ) You also need to fit the smaller flywheel to the S-4 crankshaft but need it to be custom so it has the correct trigger wheel for the S-4 timing sensor....... that ring must be correctly indexed and tack welded in place.
Is there some reason one cannot use the S4 manual flywheel with the correct ring?
12-15-2018, 05:04 PM
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12-15-2018, 10:10 PM
#12
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I tell everyone the same exact thing:
"If you have a 928 with an automatic transmission and you really have to have a 928 with a manual transmission....sell your automatic and go buy a manual."
"If you have a 928 with an automatic transmission and you really have to have a 928 with a manual transmission....sell your automatic and go buy a manual."