The next size up from the T25, the T28 series of turbochargers are more serious items. They are used in twin form on the Nissan Skyline GT-R and singularly on the Pulsar GTi-R, S14 and S15 series Silva/200SX. They make a decent upgrade for the S13 series of cars when more than 150kW are reliably expected to be produced.
Car of Origin: Nissan S14 200SX pre-1996
Engine: SR20DET
Flange: Four-bolt, same as the T25 series.
Max. Power Rating: Approximately 170kW
Max. Boost: 1.2bar (17.4psi)
Cover Size: Exhaust 0.64 AR, compressor 0.60 AR
Comments: The ultimate OE bolt-up to the S13 series of cars, the best part is that it bolts straight on. A good little all-round mid-range turbocharger that has proven itself to be extremely reliable in service.
Cost: Expensive due to their fitment to an Australian-delivered car. Their price starts at $650 for a second-hand unit.
Rating: Three out of five
Car of Origin: Nissan S14 200SX post-1996, S15
Engine: SR20DET
Flange: Four-bolt, the same as the T25 series
Max. Power Rating: Approximately 170kW or slightly more
Max. Boost: 1.2bar (17.4psi)
Cover Size: Exhaust 0.64 AR, compressor 0.60 AR
Comments: While the housing are the same as the earlier S14 turbocharger, the latter item has sophisticated Garrett ball-bearing internals, which guarantee a faster ramp-up to boost than the previous model. This is the pick of the T28 series.
Cost: They're hard to find second hand due to the relative scarcity of the S14 black rocker cover engines. Normally, you are best off to buy these new from a turbo supplier.
Rating: Four out of five
Car of Origin: Nissan Skyline R32, R33 GT-R
Engine: RB26DETT
Flange: Four-bolt, the same as the T25 series
Max. Power Rating: Approximately 150kW
Max. Boost: 1.3bar (18.8psi)
Cover Size: Exhaust 0.48 AR, compressor 0.60 AR
Comments: They are really only good for use on stock GT-R engines due to their relatively small exhaust housing. For some reason, they seem to be able to handle more boost before turbine failure, but there are still plenty that have let go.
Cost: Anything with a GT-R part number is expensive!
Rating: Two out of five
GARRETT RB20/25 SERIES
Even though many tuners refer to the RB20 and VG30 (single) turbochargers as being a T3, this is not the case. Being a Nissan-branded item and having only Nissan identification markings on them (no AR markings etc.) can make identification difficult. All of the ball-bearing turbos have a telltale 'fatter' centre core section, as well as a bolt through the centre housing, which looks as though it has an effect on the thrust bearing pre-load. Overall, these turbos are very good performers.
Car of Origin: Nissan Skyline R31 GTS
Engine: RB20DET NICS (ribbed rocker cover)
Flange: Four bolt T3 style
Max. Power Rating: 140kW
Max. Boost: 1.2bar (17.4psi)
Cover Size: AR not identified
Comments: A poor-performing turbocharger that was only used on a handful of engines by Nisan before being replaced with the newer technology ball-bearing units. Top-end power is far from good, and the actual response (boost-response time) is also quite poor. It's one to steer away from.
Cost: Dirt-cheap, as they are not in any demand. They have been seen to be as low as $100.
Rating: One out of five
Car of Origin: Nissan Skyline R32 GTS-t
Engine: RB20DET ECCS (silver rocker cover)
Flange: Four bolt T3 style
Max. Power Rating: 160kW
Max. Boost: 1.2bar (17.4psi)
Cover Size: AR not identified
Comments: A big step in the right direction from both Nissan and Garrett. A truely nice turbocharger, complete with modern aerodynamics and ball bearing construction. It's a perfect choice to get the best from an internally stock, standard injector/management set-up. On a CA18 with a custom manifold, they are really good things.
Cost: Reasonable, with some examples floating around the importers for as little as $400. You have to be quick thoughm as they tend to sell fairly quickly.
Rating: Four out of five.
Car of Origin: Nissan Skyline R33 GT25-T
Engine: RB25DET
Flange: Four bolt T3 style
Max. Power Rating: Approximately 185kW
Max. Boost: 1.2bar (17.4psi)
Cover Size: AR not identified
Comments: The big daddy of the range makes the RB25 turbocharger good for almost any mild six-cylinder application. Sparkling boost response in the low-rpm range and a reasonably hard-hitting top end make this the most common upgrade found on the RB20DET. It's highly recommended.
Cost: Being very difficult to get hold of makes them highly variable in price. Sometimes about $700, sometimes more.
Rating: Five out of five.
Car of Origin: Nissan Gloria, 300ZX
Engine: VG30DET
Flange: Four-bolt T3 style
Max. Power Rating: 190kW
Max. Boost: 1.2bar (17.4psi)
Cover Size: AR not identified
Comments: Apparently, these are slightly larger in exhaust housing size than the RB25, but have a fractionally smaller and different trim compressor. Information on these is sketchy, but due to their almost unknown application they are easier to find than the RB25 roller. A good choice, particularly if you put the RB25 compressor and cover straight on. In excess of 200kW have been produced with this combination.
Cost: Fractionally cheaper than the RB25 turbo and not as hard to get. They have been advertised at $650.
Rating: Four out of five