JZA80 CT20 Turbochargers

Japanese CT20 Ceramic Turbocharger Specs

The Japanese CT20 Ceramic Turbocharger specifications and detailed information.

Below you will find detailed specifications and facts on the JDM JZA80 CT20 ceramic turbochargers along with known limitations of these turbochargers.

The CT20 turbocharger is found in pairs on the 2JZ-GTE, which is commonly found in the JZA80 Supra and the JZS147 Aristo. There is the misconception that the JDM turbochargers are CT12B’s – this is incorrect and I will explain why below.

CT12B Series Of Turbochargers Details

The CT12B series of turbochargers use a 7.5mm turbine shaft while the CT20 series use a 10mm turbine shaft. The dimensions on the turbine wheel are identical to that of other CT20’s found on such vehicles as the LJ70 Series Landcruiser (2LT – 2.4ltr Turbo Diesel), LN60/61 Hiace & LH51 Hilux which run a CT20 with identical turbine wheel dimensions, shaft diameter and blade count.

toyota-six-speed-dual-clutch-transmissionThe CT20 utilises an aluminium compressor wheel and a ceramic turbine wheel and uses bronze bushing bearings and carbon seals. The turbo itself generates around 10lbs in standard form on the 2JZ-GTE and they have been known to successfully run around 18lbs and above, however the general consensus is that 18lbs is the absolute limit for this turbocharger if you want any form of reliability from them and even then it’s a gamble, for ultimate reliability 14.7lbs (1 bar) is the number to run them at.

The A/R of the exhaust housing on CT20 is .35 while the compressor housing runs an A/R of .36, although this is a small A/R Toyota has done this so the turbochargers offer minimal lag and maximum response. The turbine housings are of high nickel content and utilise a 3 stud inlet flange and a 5 stud outlet flange.

The turbochargers themselves are identical in size with the exception being the rear turbochargers exhaust housing which is 23.7mm longer and does not contain a wastegate, instead it contains an exhaust bypass valve which is used in the sequential operation to transition this turbocharger online with the primary (#1) turbocharger so both turbochargers are producing equal amounts of pressure and flow.

It is to note that the secondary turbocharger has a slightly larger outlet pipe (4.8mm larger) in the cast elbow however this slight gain in diameter is offset by the restriction of the EGCV located further down the dump pipe.

If you feel this is information is in any way incorrect or you can provide further information please do not hesitate to sign up on the forums and provide some useful feedback so I can make this article as accurate and detailed as possible.

*Secondary turbocharger does not utilise a wastegate, it is an exhaust bypass valve used to match compressor speeds with the primary turbo prior to the second turbocharger being brought online.

Manufacturer Toyota (Hitachi)
Type CT-20 (PN: 17201-46020 (Front), 17208-46020 (Rear)
Turbine size (Outlet diameter) 48mm
Turbine size (Inlet diameter) 59.8mm
Turbine blade count 10
Turbine material Ceramic
Turbine Housing Inlet (ID) 36mm
Turbine Housing Outlet (ID) 50.1mm
Turbine Shaft Diameter 10mm
Turbine housing A/R 0.35
Compressor size (Inlet diameter) 37mm
Compressor size (Outlet diameter) 62mm
Compressor blade count 10
Compressor material Aluminium
Compressor Housing Inlet (ID) 49.8mm
Compressor Housing Outlet (ID) 32.4mm
Compressor housing A/R 0.36
Bearing ID 10.05mm
Bearing OD 15.9mm
Bearing Width 8.96mm
Bearing material Bronze
Bearing oiling holes (per bearing) 6
*Wastegate size (ID) 26mm
**Maximum Wbastegate size (ID) 28mm
Actuator spring rate 10lbs

*Secondary turbocharger does not utilise a wastegate, it is an exhaust bypass valve used to match compressor speeds with the primary turbo prior to the second turbocharger being brought online.
**This is the maximum allowable ID before the wastegate flap itself needs be replaced with a larger item. The viability of doing this would be only beneficial if you were doing this modification yourself and even then the gains are negligible

  • Turbine outlet (Cast dump) #1 turbocharger (OD):  47.8mm
  • Turbine outlet (Cast dump) #2 turbocharger (OD):  52.6mm
  • EGCV outlet housing – outlet for #1 turbocharger (OD):  46mm
  • EGCV outlet housing – outlet for #2 turbocharger (OD): 50.3mm
  • EGCV outlet housing OD: 56.3mm
  • O sensor hole (OD): 15.5mm

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