911 Turbo S2 Engine

The 964 based Type M30/69 3.3 liter turbo engine was an extension of the 930/68 engine used in the previous 1989 911 Carrera turbo with added characteristics of the 964 engine. Mounting bosses, crankcase bolts and head fins all mirrored the 964 design. As with 964 engine there was no engine-mounted oil cooler on the engine the oil cooler mounted in the right front wheel arch. The exhaust system had two tail pipes, one from the final muffler and one from the wastegate muffler. Finally, engine power was lifted to 315HP by use of a less restrictive catalytic converter, a new larger intercooler, and an improved digital ignition.

s2engine-1Based upon this new specification then head of Porsche’s customer racing department Roland Kussmaul developed a series of turbo engines for the IMSA Supercar series. These engines featured special camshafts, enlarged and polished induction ports for frictionless flow at slightly higher boost pressures, a different K27 turbo charger (a Type 7006 later used on other 964 Turbo S models), and a modified intercooler (thicker). To meet IMSA regulations this same engine was to be issued in July 1991 as part of the specification of the 1992 Turbo S2. IMSA classes.

 

 

 

 

 

The Turbo S2 was not officially issued a specific engine Type, which could have raised NHTSA scrutiny, only a modification parts list. Officially rated at 322HP, only 7HP more than the standard 315HP M30/69 3.3 liter engine – and often incorrectly speculated to be the same as the Type M30/69SL engine of the later model 1992 Turbo Leichtbau – the engine was based upon the 355HP X33 type M30/69S engine which had been an available upgrade on the 1991 Turbo from late spring 1991 (X33 option cars – 22 produced in 1991 and 170 in 1992). Although it has been referred to as Type M30/69S, that designation is ‘officially’ reserved for the X33 option which features a different parts list.

 

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The 911 Turbo S2 parts list featured 964 cam shafts, a modified turbocharger and intercooler but retained stock cylinder heads. It differs from the X33 M30/69S WLS (Werks LeistungsSteigerung or Factory Power Increase) option which retained the stock turbo charger and intercooler but added special 930 cam shafts and modified cylinder heads. The following information on the 911 Turbo S2 is from the factory technical bulletin.

911 Turbo S2 Parts

X33 Option M30/69S WLS Parts

 

The 911 Turbo S2 engines were never officially dynomometered but the engine’s performance was heavily biased toward maximum power at high rpm, at the expense of low-end torque, which was congruent with the philosophy behind turbo charged Porsche racing engines. It is not clear if the engines received the same porting and polishing treatment of the race engines or if this labor intensive treatment was skipped as the engines otherwise had stock cylinder heads.