Different Strokes ....
Jim are you comparing to US Impulses or OZ/NZ ones? Because you also mention a LSD, well in the U.S. the LSD was listed as an option, but so far I have been told it never actually existed on the U.S. models. This from people like Bob AND a Isuzu Impulse guru I know as well.
I thought the Turbo/Non-turbo were the same up to the late 89 Lotus suspension version (w/ independant Rear end).
Guess when I did the project so many years ago I went with what was in the junkyard.. very little research at the time.
Charles - et al,
The Isuzus here are 2nd hand Japanese home market ones so it is becoming clear that the smaller rear discs may not have been exported to the U S A
I have one 1985 Turbo torque tube diff which has the larger vented rotors on it but all the others I have seen had the smaller solid disc. Note: I did say "Turbo" with the torque tube diff too! 1986 - 89 Turbos did have the five link diff here too - Isuzu must have found that 180 ps shortened the life expectancy of the torque tube diff!
Of the seven Piazzas that have gone through my hands only one has had an LSD - an automatic, 1984, "Nero" top of the line model which also had the twin cam motor.
The Aussie ones were sold as "Holden" Piazzas with the turbo motor and only 156 were imported. They actually had the Holden "Lion" insignia in the grilles and "Holden" on the rear.