The KKK K26 turbocharger
K26-6 and K26-8: which charger sits in which Turbo, how to tell them apart and what defines the design.
In short: Up to 1988 the Turbo has a K26-6; from the 1988 Turbo S onwards a K26-8 with a larger turbine that holds boost to higher revs.
Design
The charger has a water-cooled bearing housing; an electric pump circulates the coolant. It sits on the side of the engine away from the exhaust and is fed by an insulated crossover pipe – which noticeably lowers inlet temperatures.
K26-6 or K26-8?
A simple feature helps: the K26-6 has a square flat spot of about one inch on the turbine housing, visible with a torch next to the oil dipstick, looking from the front at an angle. The K26-8 lacks it.
On modified cars the charger may have been swapped. Without records, the car’s history does not tell you which charger is fitted.
Care
The charger works together with boost control, wastegate and intercooler – see their own articles. The electric after-run pump should run after shutdown (see the water pump article).
Technical values
Only work with the workshop manual and the correct tools. Do not use unverified values without checking them – wrong tension values can destroy the engine.
Sources
- Secondary source 944 Turbo (951) FAQ
Secondary source on the Turbo: charger, boost, wastegate, model years. Some figures quoted from the workshop manual, unverified here.
- Secondary source K26 Turbocharger Identification
Telling K26-6 from K26-8.