all i know that they are smaller than all the other nissan factory t28's(s14,s15). r33 ones were bigger. my mate bought one cheap for his ca but found out it wasnt worth the hassel of swapping.
here found this:
Nissan/Garrett RB26DETT (T28 style)
The Skyline GT-R engine uses a pair of T28 turbochargers to achieve its 206kW claimed output.
Just one of these turbochargers can be employed on engines making about 120kW, so long as the ceramic turbine isn't pushed beyond its limits. A single R32 GT-R turbo is ideal for, say, a 1.5 litre four cylinder with a few breathing mods.
The GT-R compressor inlet is 53mm diameter but, again, we were unable to measure the discharge nozzle diameter. The compressor is marked with a 0.48 A/R ratio. On the opposite side, the GT-R turbo uses a 38 x 50mm turbine passage and a 63 x 93mm mounting flange. The turbine housing is also marked with a 0.54 A/R. The mounting flange and dump pipe are 4-bolters.
Note that this turbocharger uses the same turbine mounting flange as the S14/S15 200SX, Pulsar GTi-R and various other Nissan turbos. This makes conversions easy.
found it here
hope it helps
