TURBO ENGINES

The 2.2 & 2.5 engines began in 1981 as a carbureted engine only. The first turbo engine was in 1984 with port fuel injection and a Garret air research turbo charger had a rating of 142 hp. This was done with 2 computers one being called the logic module located in the passenger side of the car to the right of where passenger foot well is, and a power module located beside the battery.
1985 there was some upgrades one being upgraded logic and power modules and a better vacume controlled wastegate controller. Power was up slightly to 146 hp. And torque was up to 168. 1985 had the same Air research turbo but was upgraded to being water-cooled.
1986 was the first year for the Turbo II engine with intercooler and new intake manifold. All 86 engines had a swirl heads to decrease emissions and had the larger head bolts (they went from 10 mm to 11mm) for better clamping force. 86 was the first year for the 2.5 TBI engine, this was the same basic engine with increased deck height and incorporated balance shafts. There were some small upgrades done to the computers but nothing major.
1987 most things stayed the same except for moving the map sensor from being in the logic module to under the hood; the other thing that changed was the use of a 3 lead oxygen (from a single lead) sensor. The L body cars did not get either of these changes.
1988 saw even more changes; one being all turbo engines were fitted with the high-rise blow through intake manifold. All engines were fitted with roller cam followers to decrease emissions and to get better idle quality. The turbo I engine received Mitsubishi turbo chargers for increased bottom end torque, while the turbo II engine still used the Air research turbo. This was the first year that the 3.0 was available with auto or 5 speed. The big change for electronics was the use of a SMEC (single module engine controller). This was the same function as other years but they combined both the logic and power module in one case located beside the battery.
1989 was the first year for the common block. This is great news for the people trying to push the horsepower past 300. It was greatly reinforced and all engines (2.2 & 2.5) shared the basic block turbo or not. 2.5’s once again had balance shafts and 2.2 turbo II engines did not. Turbo I engines were 2.5’s with Mitsubishi turbo chargers. The way to identify one of these blocks is the cast over fuel pump mount. Also in 1989 was the first year for the VNT (variable nozzle turbo) turbo. This was built to get of turbo lag, horsepower was the same but low-end torque was increased. All 1989 cars were equipped with SBEC (singe board engine controller) but no major electronic changes. This is the wiring harness that the super 60 package was built for. This is the first year for the 2.5 turbo I mini van.
1990 saw a larger production of the 2.2 turbo IV (VNT) engine. I believe this engine had balance shafts like the 2.5. The SBEC connector was changed to a single connector. All other engines stayed the same, this is the last year for the 2.5 turbo I mini van.
1991 saw the introduction of the turbo III, this was a DOHC engine with 224 hp. It had a head made by Lotus and had DIS (distributor less ignition system) This engine was available in the Sprit RT only. There was no VNT turbo or Turbo II engines.
1992 saw very little changes except that the Daytona IROC could be fitted with the turbo III. Still you could get a turbo I.
1993 only had one turbo engine available, it was the Turbo III in the Daytona only. The 2.2 and the 2.5 were available in TBI form only. This was the last year for these engines. The 2.0 and the 2.4 engines were fitted in the new cars.