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