The CT20B turbocharger that is one of the most sought after upgrades for the 3S-GTE engines in MR2’s and Celica’s, it came standard on all GEN III 3S-GTE motors. The CT20b is designed by Toyota and manufactured by Hitachi.
The CT20b has a working pressure of 11.9 – 16.7psi which is very similar to the CT26 but still higher, the main advantage of using a CT20b over the CT26 is that the CT26 has a steel shaft and wheel where are the CT20b uses ceramic. Due to a revised and more efficient compressor wheel the CT20B will spool slightly slower but has more top end gains and although the ceramic is lighter and spools faster it is severely weaker than steel. The CT20b will hold boost right through to red line where as the CT26 starts to drop off at about 5500rpm, Max boost on a CT20b is 18-19psi but that is well outside of the efficiency range of the turbo and being over its limits it increases the chance of breaking the wheel and snapping the shaft.
The CT20b is rated at 400hp which is close to 280-300 rwhp so all in all it’s a excellent bolt on upgrade as 15-16 psi is approximately a 37 percent power increase over stock which is perfect for those who prefer a mildly worked street-able car.