900 Turbo 8-Valve Intercooler Installation

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Project description

Skill level: Intermediate

Time to complete: ~20 hours

Special tools: None.

Much of the turbo plumbing and intake system is disassembled during this project. Some engine components are relocated and the coolant must be partially drained. New brackets and ductwork is installed which may require some drilling. Here is a breakdown of the major issues:

Eliminate decel bypass system (manual transmission models only) The deceleration system is a valve that bleeds vacuum from the intake system when the car is in gear with the throttle closed. This causes the fuel injectors to close during deceleration and reduces exhaust emissions. Eliminating the decel. system will not effect the drivability or performance of the engine however it will effect it's deceleration emissions.

Eliminate preheat system The preheater system is a simple airbox and hose that allows warm air from the exhaust area of the engine to enter the intake to assist in cold-weather starting/running. There is no data on what effect removing this system may have in very cold-weather startup conditions. This author has never experienced a cold-start issue due to the loss of the preheater.

Move Oil Cooler The stock oil cooler must be removed from its position under the left headlight and moved under the right headlight. There are two choices here: The stock oil cooler can be relocated (it's lines must be lengthened) or a 16V oil cooler with 16V lines and fittings can be installed. The stock oil cooler was fitted with longer lines and relocated for this project.

The oil cooler in it's stock location. Note that oil supply lines cross directly over the area where the intercooler will reside.

The oil cooler removed exposing direct path to fresh air from the front of the car and allowing room for the intercooler installation.

Moving the oil cooler does two things. First, it allows the 900 Turbo 16-valve intercooler to fit in it's stock location using stock brackets and ductwork. Second, it allows fresh, cold air from the front of the car to reach the intercooler without having to pass through the oil cooler first.

Horn The horn must also be relocated to make room for the repositioned oil cooler.

Lower radiator hose It is also necessary to replace the lower radiator hose with one from a early 16-valve 900 Turbo. The stock 8-valve hose will not allow the clearance necessary to fit the intercooler. This will require a partial draining of the coolant system.