Twin turbo Carrera engine and trans in Boxster
10-19-2005, 10:50 PM
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Racer
Join Date: Sep 2003
Location: San Antonio, TX
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all of the boxster turbo applications i have come across used the wet-sump M96 block. however, the dry-sump GT3 engine has been swapped into at least two boxsters in the US and several by tuners in germany.
the wet sump and dry sump engines have drastically different bolt patterns mating to the transmisison, so a 986/996 tranny wouldn't work. one of the US GT3 boxsters used a custom hewland transmission to mate up correctly. a GT3 transmission would work if the pinion gear was modified in order to transfer power the other direction, so you don't have 6 reverse gears and 1 forward gear. and there are obviously linkage issues to be worked out.
the physical dimensions of the dry sump engine are also a problem as the boxster's engine compartment is very snug around the front upper part of the engine due to the space required to store the convertible top in the down position. the GT3 engine has a larger intake manifold that requires either the removal of the convertible top or a custom manifold that does not intrude on that space.
i'd love to see more dry-sump boxsters! but it seems that the amount of custom work drives the costs too high at this point. i'm hoping tuners will experiment with this swap in the cayman S as the engine cover could easily be modified to accomodate the larger GT3 manifold. it's such a shame that porsche does not offer the "track-worthiness" and reliability of the dry-sump block in a mid-engine car (besides the CGT).
the wet sump and dry sump engines have drastically different bolt patterns mating to the transmisison, so a 986/996 tranny wouldn't work. one of the US GT3 boxsters used a custom hewland transmission to mate up correctly. a GT3 transmission would work if the pinion gear was modified in order to transfer power the other direction, so you don't have 6 reverse gears and 1 forward gear. and there are obviously linkage issues to be worked out.
the physical dimensions of the dry sump engine are also a problem as the boxster's engine compartment is very snug around the front upper part of the engine due to the space required to store the convertible top in the down position. the GT3 engine has a larger intake manifold that requires either the removal of the convertible top or a custom manifold that does not intrude on that space.
i'd love to see more dry-sump boxsters! but it seems that the amount of custom work drives the costs too high at this point. i'm hoping tuners will experiment with this swap in the cayman S as the engine cover could easily be modified to accomodate the larger GT3 manifold. it's such a shame that porsche does not offer the "track-worthiness" and reliability of the dry-sump block in a mid-engine car (besides the CGT).
