Tuning a Toyota 3s-GTE

A Brief History

 Since Toyota stopped building sports cars in favour of minicabs, its easy to forget their turbocharged, rally - bred weaponary. Chief among many is the 3s - GTE despite dating back more than 20 years, this 1998cc, four - cylinder, twin- cam, 16v engine is still a force to be reckoned with. The Yamaha - built engine first appeared in the 1986 Celica GT - four ST165, giving 182bhp. It was then altered for the 1989 Celica GT - four ST185, changing from an intercooler and CT26 turbo. By this time it was producing 201bhp. The biggest leap came in 1994, when 3S - GTEs were upgraded in both the Celica (now the ST205 model) and MR2. The airflow meter was dropped in favour of a MAP sensor, and other modifications including better head design, steel head gasket, bigger injectors and superior chargecooled CT20B turbocharger with increased boost. Tuning requires a varied budget depending on the level of performance you wish to get out of the engine but I will explain seven major steps from spending £550 - 850 all the way to £12,000 in tuning a 3S - GTE.

STAGE 1.

This will give the engine an increase of between 215 to 255bhp and will cost in the region of £550 to £850. So the first place to gain more power from any 3S GTE is to improve its breathing ability and remove the stock restrictions. Start with a free - flowing induction kit, then move on to the exhaust. Any full system should see benefits, but if you're planning on eventually going over 300bhp, look for one with at least 3in internal bore - it'll save you cash in the long term. Most importantly bin the catalytic converter in favour of a decat pipe. The standard elbow after the turbo has a bend of more than 90 degrees. Most decats smooth out this bend, aiding gas flow and adding up to 10bhp. Now the throttle response will be improved but massive performance hikes wont be noticed just yet.

STAGE 2

This will give the engine a increase of between 235 to 285bhp and will cost in the region of £200 to £225. Now it's time to increase boost pressure, and though it's easy to do with a £20 bleed valve, that's a bit agricultural now. A better bet is to fit and set up an electric boost controller. On a rev 3 - onwards model, this allows boost to be raised to 17psi (and 285bhp). Earlier (rev 1 and 2) engines have an airflow meter that maxes out at 12psi boost, but can be increased to 15psi using a fuel cut defender to limit boost pressure.

STAGE 3

This will give the engine a increase of between 300 to 330bhp and will cost in the region of £2,600 to £3,250. This is where its gets intresting ive already explaned how to raise turbo boost to the limits of the standard ECU, so there's a two - step process to achieving Stage 3. The first is to impove cooling to reduce intake temperatures. This is especially necessary on an MR2, which gets pretty hot in the engine bay. One soloution for this is to fit the chargecooler from an ST205 or ST185 RC.  You can then add a fuel controller. With suitably increased boost, the engine should be now looking at 330bhp.

STAGE 4

This will give the engine a increase of between 400 to 800bhp and will cost in the region of £3,250 to £5,000. Although American - tuned 3S - GTEs have been known to produce 400bhp on standard internals, Stage 3 reached the realistic limits of the original bottom end. That's not to say it's weak. All cranks are forged and will take 800bhp no probs. Likewise, the stock con rods are good for 700bhp. That said, most builders fit forged rods while the engine's apart - a good security measure. What will help with the engine is a set of forged pistons. A new clutch for power outputs much above 300bhp will help the engine also.

STAGE 5

This will give the engine a increase of between 350bhp to 400bhp and will cost in the region of £1,400 to £1,800. With the bottom end rebuilt, the engine is now ready to start making more boost and adding the fuel to feed it. There is a wide choice of hybrid turbos out there nowadays but a ball bearing unit would suit the engine better, a fuel injection system upgrade will also be needed for the engine at this stage. Large front - mounted intercooler system will be a wise choice also at this stage.

STAGE 6

This will give the engine a increase of 440bhp + and will cost in the region of £1,500 to £5000. At this stage it's worth looking at the engines top end - gas flowing, porting and polishing the cylinder head. Inside the head fit uprated cams (and adjustable pulleys) with increased duration or higher lift depending on the desired benifits. Stroker kits to increase the cylinder capacity to 2.2 litres is advised. For safety's sake line the cyclinder bores there will be immense torque.

STAGE 7

This will give the engine a increase of 500bhp + and will cost in the region of £10,000 to £12,000. For the ultimate 3S GTE a bigger turbo is needed, roller - bearing units are well respected. These turbos will require a stainless tubular exhaust manifold, enlarged throttle body, reworked chain and titanium valves larger injectors wil help also. Any bigger than 850cc require a top - feed fuel rail. Depending on the mods a properly set - up 3S GTE can gain 80bhp through the use of more detonation - resistant fuels.

HAPPY TUNING!