Flow Meter is also removed in favor of a MAP sensing system (prior generations used a MAP sensor only for the purpose of the factory boost gauge and determining overboost fuel cut). Various increases included injector size (540 cc), boost (13 psi), overboost fuel cut limit (18 psi), intake cam lift (), throttle body size (), and a increase in exhaust ports. Exhaust valve lift is retained at . In late 1997, the block casting was revised with added support around the head to prevent block cracking problems. The C20b turbo found in this generation is backwards compatible with the second generation motors, however not the first generation. Further improvements include a factory oil catch can. Compression is reduced down to 8.5:1 however power is improved to and . Fourth Generation The fourth-generation engine uses a proprietary CT15B turbocharger. This generation was used in the Toyota Caldina GT-T AWD Wagon (ST215). The exhaust housing is actually cast into the cylinder exhaust manifold, rather than the normal practice of a separate turbine housing after the cylinder exhaust manifold. Due to this, the CT15 is backwards compatible with the third-generation 3S-GTE cylinder head only, not either the first or second generation. Intake charge was cooled by an air-to-air top-mounted intercooler fed through a new side-feed intake manifold. This generation utilizes a coil-on-plug ignition system and 550 cc injectors. Boost remains at 13-14 psi, however overboost fuel cut is increased to 21 psi. Compression is increased to 9:1 and produces and . Fifth Generation The fifth-generation engine uses the same turbo as the fourth generation model. This generation was used in the Toyota Caldina GT-Four (ST246). There are only minor differences to this engine compared to the previous version and due to only limited markets receiving the ST246, very little is known and very few are aware of the engine. Differences include longer injectors to be closer to the intake ports. The intake manifold returns to a center-feed type fed by an air-to-air top-mounted intercooler. This intercooler is slightly smaller than the previous generation and is oriented slightly different than any of the previous generations. It is tilted more towards the front of the car. The coil-on-plug ignition is different in this generation and it is not compatible with the ST215 ECU. The valve cover is different as for the first time in the 3S-GTE series as the oil filler hole is on