Updated 17/03/00

GT-R RHF6CB Turbocharger

Turbo Charger cutaway

Turbocharger and Intercooler
The turbocharger was specifically developed for the GT-R application by IHI. The RHF6CB turbocharger has a 62.0mm turbine and a large 65.0mm compressor. By comparison the turbo for the type BPD 1.8-litre engine that powers the 323 4WD GT-R has a 52.5-mm diameter turbine and a 52.5-mm compressor. It is commonly believed that a big turbo is employed for high rpm power. The Mazda and IHI teams have proven with the GT-R turbo installation that this is not necessarily so. They have sought and achieved an optimum balance between high power and quick mid-to-high rpm response. A relatively small "A/R" ratio, a value of 16 to the GT-X's 15, was one of the means they adopted to assure these desirable characteristics. "A" is the turbines smallest scroll area and "R" the distance between the turbine-shaft center and the center of area "A", the two factors used in calculating turbocharger's performance characteristics. 

The turbocharger employs a steel turbine wheel for its proven reliability under the rigors of competition. In Mazda's testing it suffered little in responsiveness when compared with a unit fitted  with a experimental ceramic turbine; the latter may be decelerating too quickly for any appreciable difference in pickup that follows. 

The turbocharger shaft is supported by ball bearings, which improves turbo response by as much as 7 percent by Mazda's testing.The turbocharger is watercooled. Boost is controlled by a dedicated computer map, and it s maximum pressure is 450mm of mercury(Hg).

The standard air-to-air intercooler is about twice the size of the unit fitted in the 323 4WD GT-X (235-mm wide,225-mm high and 65-mm deep), and has a heat dissipating capacity of 6,150 Kcal/hour which is 36 percent more than the GT-X's. It features efficient "zig-zag" fins which increase cooling surface area. The intercooler is located in the nose of the car, immediately ahead of the coolant radiator. the path the boosted air takes to the engines intake system is as direct and short as possible, so that pressure loss is minimized.

Source:Product Information  Mazda 323 4WD GT-R ; Mazda      

RHF6CB turbocharger

Source:Product Information  Mazda 323 4WD GT-R ; Mazda