Limited Slip or Welded Differential?, "Pros", "Cons", "How To Dos", and " Options

[Eddie914]

What are the "Pros", "Cons", "How To Dos", and "Been There Done That's" regarding reducing the slip for 914 sideshift differentials?

I have a rebuilt (or so said the PO) 914 sideshift 914 transmission in the 1971 3.2 conversion teener. It works well. It shifts well, all the synchros seem solid, it doesn't make any unusual sounds and stays in gear (after new engine mounts were installed).

Also in my inventory of used parts are a 1986 Carrera 915 Limited Slip transmission and a spare 914 sideshift transmission. The 915 came from a wrecked (nasty side impact with a tree at the B pillar) 911 Carrera with 85,000 miles. The spare 914 Sideshift was purchased on ebay and is of unknown working condition.

Option 1: Install the LSD from the 915 into the 914 SS transmission currently installed in the teener. The local Porsche transmission shop said that the 915 LSD will NOT fit in the 914/901 transmission. Grady Clay indicated on the Bird Board that he has done the swap. Are substantial modifications required? Has anyone BTDT?

Option 2: Weld the differential in the spare 914 SS transmission. Can the differential be welded with out completely disassembling the transaxle (removing the side cover and welding the spider gears while the differential is still installed in the case?

I use the teener mostly for track events. I have not yet autox'd the teener but may do so when my son turns 16 in about 4 months.

The 914 is currently running 944 Turbo CV joints with 914 axles. I also have a set of Sway-Away Slider axles with Carrera CV's that are compatible with the output flanges on the 915 LSD. I think I have all the parts required to utilize both of these options ( and a few variations ...).


Thanks


Eddie