Toyota 3S-GTE engine
The 3S-GTE is an in-line 4-cylinder 1998 cc engine from Toyota, based on the 3S-GE with the addition of under piston oil squirters and a reduced compression ratio to accommodate the addition of a turbocharger.
There are four generations of this engine, which started manufacture in 1986 and was built until 2007. The turbochargers used in the 3S-GTE engines are Toyota designs and use an internal wastegate design. Depending on where the engine was intended to be sold the exhaust turbine is either ceramic (Japan) or steel (US and Australia). It was fitted to the MR2, Toyota Celica GT-Four, and the Caldina GT-T and GT-Four.
|3S-GTE usage in Toyotas|
|1||1986–1989||Celica ST165||185PS(182HP) @ 6000rpm
190HP @ 6000rpm (North America)
|250 N·m (184 lb·ft) @ 4000rpm
258 N·m (190 lb·ft) @ 4000rpm (North America)
MR2 (1990-1992 Turbo)
MR2 (North America 1991-1995)
|200HP @ 6000rpm (North America)
205HP @ 6000rpm (UK/Australia Group A Rallye)
225PS(222HP) @ 6000rpm (ST185/MR2)
235PS(232HP) @ 6000rpm (ST185 RC)
|271 N·m (200 lb·ft) @ 3200rpm (North America)
281 N·m (207 lb·ft) @ 3200rpm (UK)
275 N·m (203 lb·ft) @ 3200rpm (Group A Rallye)
304 N·m (224 lb·ft) @ 3200rpm (ST185/MR2)
304 N·m (224 lb·ft) @ 4000rpm (ST185 RC)
MR2 (1993+ Turbo except for North America)
|245PS(242HP) @ 6000rpm (MR2)
255PS(251HP) @ 6000rpm (ST205)
|302 N·m (223 lb·ft) @ 4000rpm (ST205 Group A)
304 N·m (224 lb·ft) @ 4000rpm
|4||1997–2001||Caldina ST215 (GT-T)||260PS(256HP) @ 6200rpm||324 N·m (239 lb·ft) @ 4400rpm|
|4.5||2002–2007||Caldina ST246 (GT-Four)||260PS(256HP) @ 6200rpm||324 N·m (239 lb·ft) @ 4400rpm|
Its cylinders are numbered 1-2-3-4, cylinder number 1 is beside the timing belt. The Dual Over Head Cam (DOHC) 16-valve cylinder head designed by Yamaha is made of aluminum alloy. The pent-roof combustion chambers are complemented by a cross flow intake and exhaust layout. Spark plugs are located in the middle of the combustion chambers. A distributor based system is used to fire the cylinders in a 1-3-4-2 order.
The crankshaft, located within the crankcase, rotates on five aluminum alloy bearings and is balanced by eight weights. Oil holes are located in the middle of the crankshaft to provide oil to the connecting rods, bearing, pistons and various other components.
A single timing belt drives the intake and exhaust camshaft along with the oil and water pumps. The cam journal is supported on 5 points between the valve lifters of each cylinder and on the front of the cylinder head. The cam journals are lubricated by oiler port located in the middle of the camshaft. To adjust the valve clearance in the first two generations, a shim over bucket system is employed. In the following generations a shim under bucket system is used.
The pistons are made from an aluminum alloy designed to withstand high temperatures. An indentation is incorporated into the pistons to prevent the pistons from “knocking” into the valves. Piston pins holding the pistons in place are locked by snap rings.
The first compression ring and the oil ring is made of steel, the second compression ring is made of cast iron. Compression ring 1 and 2, prevents gas leakages from the combustion chamber while the oil ring works to clear oil off the cylinder walls, preventing any excessive oil from entering the combustion chamber.
The first-generation Toyota CT26 utilized a single entry turbine housing and a single wastegate port design. It was fitted to the first generation ST165 Toyota Celica GT-Four. The intake charge was cooled by a water-to-air intercooler and the intake manifold design is Toyota’s T-VIS. It has 8 independent ports and benefits from the inertia build up to improve engine torque at low and medium speeds by closing 4 ports below a certain RPM and throttle position to increase air speed and maximize fuel atomization and opening all 8 at higher engine loads for better air volume. Air metering is through an Air Flow Meter and there is no factory BPV/BOV in this generation. Fuel delivery is through 430cc injectors while air is fed through a 55mm throttle body and 7.15mm intake and exhaust valve lift. Compression ratio is 8.5:1 and produces 182-190HP and 190 lb-ft with a factory 8-9psi of boost. Fuel cut is at 12psi.
A second-generation 3S-GTE
The second-generation Toyota CT26 used a twin entry turbine housing with dual wastegate ports. It was fitted to the second generation ST185 Toyota Celica GT-Four as well as the SW20 MR2 Turbo. The intake charge is cooled by an air-to-air intercooler either top-mounted in the Celica or side-mounted in the MR2. The rally homologation Celica (known as Group A Rallye in Australia, RC in Japan and Carlos Sainz Limited Edition in Europe) used a top-mounted water-to-air intercooler and is distinguished by a hood vent rather than a hood scoop as found in the non-homologation ST185s. This generation retains the T-VIS intake manifold and the Air Flow Meter. A factory BPV is included in the SW20 MR2 Turbo but not on the Celicas. Compression ratio is 8.8:1 and produces 200-232HP and 200-224 lb-ft. This generation retains the injector size and throttle body size from the previous generation. However, boost is increased to 10-11psi in the ST185 and MR2 while it is increased to 16psi in the ST185RC. Intake and exhaust valve lift is significantly increased to 8.2mm. This generation also is known for the infamous Hose from Hell (HFH) and Hose from Hell on Earth (HFHOE) as two small coolant hoses are known to require replacement sometime after 100k miles and is sandwiched in all directions by components.
The third-generation engine uses the (enthusiast-dubbed) Toyota CT20b turbo, which was of the same design as the second-generation but with a slightly improved turbine housing and larger compressor wheel. A factory BPV is installed on all applications. The intake charge is cooled by a water-to-air top-mounted intercooler similar in shape to the ST185RC WTA. One can tell the difference as the ST205 WTA is black while the ST185 WTA is silver with a black centre. This generation does away with T-VIS and uses a normal 4 runner intake with the same port shape and size as the NA engine (but with larger injector holes for side feed). The Air 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 (540cc), boost (13psi), overboost fuel cut limit (18psi), intake cam lift (8.7mm), throttle body size (60mm), and a 10mm increase in exhaust ports. Exhaust valve lift is retained at 8.2mm. In late 1997, the block casting was revised with added support around the head to prevent block cracking problems. The CT20b 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 245-255PS(242-251HP) and 304 N·m (224 lb-ft).
The fourth-generation engine uses a proprietary CT15B turbocharger. This generation was used in the 1997-2002 ST215 Caldina GT-T AWD Wagon. 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 550cc injectors. Boost remains at 13-14psi, however overboost fuel cut is increased to 21psi. Compression is increased to 9:1 and produces 260PS (256 hp) and 324N·m (239 lb-ft).
Fifth Generation (also known as Gen4.5)
The fifth-generation engine uses the same turbo as the fourth generation model. This generation was used in the 2002-2007 ST246 Caldina GT-Four AWD Wagon. 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 of the 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 top of the exhaust camshaft instead of the intake. Other differences include the first time that there is no oil cooler in this generation as well as OBD2 diagnostics. Despite the downsize in various components of this generation, power is retained at 260PS (256 hp) and 324N·m (239 lb-ft).
|Gen 1||Gen 2||Gen 3||Gen 4||Gen 4.5|
|Capacity||1,998 cc (2.0 L)|
|Bore x Stroke||86 mm (3.39 in) x 86 mm (3.39 in)|
|Variable Performance Mechanism||T-VIS||Traditional|
|Valve Material||Steel-Alloy||Heat-Treated Steel with Nitride|
|Intake Valve Diameter||33.5 mm (1.32 in)|
|Exhaust Valve Diameter||29.0 mm (1.14 in)|
|Intake Valve Lift||7.15mm||8.2mm||8.7mm||8.75mm||8.4mm|
|Exhaust Valve Lift||7.15mm||8.2mm||8.2mm|
|Injector Size||Top-Feed 430cc||Side-Feed 430cc||Side-Feed 540cc||Top-Feed 540cc||Extended length Top-Feed 540cc|
|Turbo (All Single Turbo)||Single-Entry CT26||Dual-Entry CT26||Dual-Entry “CT20b”||Cast-in-manifold Single-Entry CT15B|
|Intercooler||WTA TMIC||ATA TMIC/SMIC (ST185RC – WTA)||WTA TMIC/SMIC||ATA TMIC|
|Factory Boost||8-9 PSI||10-11 PSI||13 PSI|
|Fuel Cut||12 PSI (ST185RC – 16 PSI)||18 PSI||21 PSI|