ANF Posted 17October, 2016 Report Share Posted 17October, 2016 Hoping someone out there, maybe Bruce Buchanan, can help me with this puzzle.....My 1983 928 S has vacuum advance and vacuum retard on the distributor. The retard side (well I assume it is the retard side?) is connected to the base of the throttle body. The advance side is currently blocked off by a rather eloquent bolt! I would assume that this is not a Porsche factory mod!I have a vacuum chart that says both of these should be connected to the base of the throttle body, I am still to find a place for the advance line, but my puzzle is that if both sides of the vacuum diaphragm are connected to the same location, will this not cancel out any vacuum effect??The car runs ok at higher revs but is lacking down low....Any help greatly appreciated. Link to comment Share on other sites More sharing options...
tazzieman Posted 17October, 2016 Report Share Posted 17October, 2016 As you know mine is an '82 ; this is my TB port setup. Is yours different? Link to comment Share on other sites More sharing options...
ANF Posted 17October, 2016 Author Report Share Posted 17October, 2016 I think it looks the same.... yours only has one vac line to distributor, is that retard or advance?I think you are on the right track and I may connect both.....Thanks Link to comment Share on other sites More sharing options...
tazzieman Posted 18October, 2016 Report Share Posted 18October, 2016 I think it looks the same.... yours only has one vac line to distributor, is that retard or advance?I have one line from the distributor vac advance canister to the rear of the TB. The retard port comes off the other side of the dizzy body and goes to the front of the TB..It was disconnected when I got the car , was connected for a while but I recently disconnected and plugged the retard line with no ill effect except improving my idle. Which as you know is very sensitive to vac leaks and other things! Link to comment Share on other sites More sharing options...
Buchanan Automotive Posted 18October, 2016 Report Share Posted 18October, 2016 The Australian delivered leaded version of the 4.7L 928S ( K - Jet ) had special emission requirements to meet , so it had the same "emission " ignition distributor vacuum set-up that only one other country received ( in that era only ) and that other country was Sweden So the Australia & Sweden version had = Centrifugal advance & Vacuum Retard ( Vacuum advance NOT connected )The Vacuum advance port on the distributor was blocked off with a red coloured blanking plug ( part number 911 110 297 00 )--------------------------------Other countries that received the leaded K-jet 928S had a different set up = Centrifugal & vacuum advance & retard mechanism, meaning both the vacuum advance & retard were vacuum connectedRegardsBruce BuchananBuchanan Automotive Link to comment Share on other sites More sharing options...
ANF Posted 18October, 2016 Author Report Share Posted 18October, 2016 The Australian delivered leaded version of the 4.7L 928S ( K - Jet ) had special emission requirements to meet , so it had the same "emission " ignition distributor vacuum set-up that only one other country received ( in that era only ) and that other country was Sweden So the Australia & Sweden version had = Centrifugal advance & Vacuum Retard ( Vacuum advance NOT connected )The Vacuum advance port on the distributor was blocked off with a red coloured blanking plug ( part number 911 110 297 00 )--------------------------------Other countries that received the leaded K-jet 928S had a different set up = Centrifugal & vacuum advance & retard mechanism, meaning both the vacuum advance & retard were vacuum connectedRegardsBruce BuchananBuchanan AutomotiveThanks Bruce. Is there anything to be gained by now connecting the vacuum advance?Cheers Link to comment Share on other sites More sharing options...
TrevMcRev Posted 19October, 2016 Report Share Posted 19October, 2016 The Australian delivered leaded version of the 4.7L 928S ( K - Jet ) had special emission requirements to meet , so it had the same "emission " ignition distributor vacuum set-up that only one other country received ( in that era only ) and that other country was Sweden So the Australia & Sweden version had = Centrifugal advance & Vacuum Retard ( Vacuum advance NOT connected )The Vacuum advance port on the distributor was blocked off with a red coloured blanking plug ( part number 911 110 297 00 )--------------------------------Other countries that received the leaded K-jet 928S had a different set up = Centrifugal & vacuum advance & retard mechanism, meaning both the vacuum advance & retard were vacuum connectedRegardsBruce BuchananBuchanan AutomotiveBruce your knowledge about these cars never ceases to amaze me! Link to comment Share on other sites More sharing options...
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