Nissan S15 Turbo
There are two turbos that came out on the S15. They are both the same apart from the fact one is a ball bearing turbo and the other is a standard plain bush bearing turbo. There has been plenty of discussion on various forums about which cars came out with which turbo. It seems the earlier cars did come out with ball bearing and the later model cars came out with the non ball bearing. Either way the turbo selection didn't seem to have a noticeable affect on performance.
It looks like cars 6 speed manual cars built between Jan 1999 and Oct 2000 got the ball bearing turbo and cars built after this got the non ball bearing turbo. Indications are that a 6-bolt housing means it's ball bearing and a 4 bolt housing means it's non ball bearing. The best way to check though is to look at the part number on the turbo. It's a small plate in between the compressor and turbine housings.
- 14411-91F00 is ball bearing
- 14411-69F00 is plain bearing
- 14411-75F00 is plain bearing, used Nov 2000 onwards
The factory spec turbo is T28
- Turbine - 53mm T25, 0.64 A/R, 62 trim 38.5mm outlet, Inconel wheel
- Compressor - 60mm Exd, 46.5mm Ind T3, 0.60 A/R, 60 trim
The factory spec turbo is pretty much the same as the Garrett GT2560R and is good for a little over 200kw at the wheels