“The 911 SC is as good as it can be made,” opined one Car and Driver scribe. “Porsche has massaged, refined, reworked, and improved on it until the car is as near perfection as it can be. And that’s why it will go away. Innovation and challenge are very important at Porsche. The 911 no longer provides either. It has outlived its usefulness, and as attrition takes the die-hard traditionalist, the 911 will finally outlive its demand.”
Despite being “as near perfection as it can be,” a fair chasm existed between the performance of the SC and its 930 big brother. Seeing an opportunity to bridge the gap, Porsche quietly set to work on the company’s very first “factory tuning kit” intended for road use. Enter Rolf Sprenger and his Department of Special Requests at the Kundenzentrum (Customer Center). Sprenger — the father of Bosch mechanical injection in Porsche’s road cars — would soon make another indelible mark on the 911 lineage with the Flachbau (Flat-nose) 930. However, on this SC-based project, the work of his team flew almost entirely under the radar. Their goal? 210 hp — the same as the revered ’73 Carrera RS.
Politics necessitated secrecy. With the 928 envisaged as the standard-bearer of Porsche’s future, it was important to position the 911 appropriately from a performance standpoint. Factory performance figures quoted 0–62 mph for the 240-hp V8 sled at 6.8 seconds for the five-speed and 8.2 seconds for the automatic, with top speeds of 143 and 140 mph respectively. Low and behold, the five-speed SC 3.0’s numbers came in at 7.0 seconds and 136 mph. The political tap-dance meant that any works-produced performance kit for the SC could not receive the press attention that would otherwise be afforded it. Inside Kundenzentrum, lips were zipped.
Sprenger’s team took the stock 930/03 engine seen in RoW SCs (930/09 for MY1980) and bored it from 95.0 to 97.0 mm, the same as the 3.3 Turbo motor. This yielded 3122 cc with the stock 70.4-mm stroke. The compression ratio was increased from 8.6:1 to 9.5:1, which necessitated the use of premium grade fuel (98 RON). An upgraded fuel distributor was employed, while pistons and cylinders were sourced from Mahle. To handle any additional cooling needs, a larger oil cooler — likely left over from the racing program and similar to the eventual 3.2’s unit — was mounted in the right front fender. Finally, a taller fifth gear of 0.759:1 (rather than 0.785:1) pushed top speed higher. In the Kundenzentrum, technician Elmar Willrett assembled the engines under the supervision of master engine mechanic Helmut Pietsch.
Output from the 3.1 rose to 210 hp at 5800 rpm and 206 lb-ft of torque at 4700. This met the goal and represented a healthy power increase of 17 percent over the ’78–’79 powerplant and 12 percent over 1980’s uprated 188 hp RoW 3.0. 0–62 mph fell to a claimed 6.5 seconds while top speed rose to a claimed 143 mph. Given the political climate, these figures were conservative. The special engine required a trip by Porsche to the TÜV for certification; of course, additional taxes and insurance requirements would be borne by the eventual buyer. While Porsche honored the standard warranty for the SC’s powertrain, buyer documentation warned that repairs to the powerplant might be difficult for dealerships to complete due to a scarcity of parts. Instead, owners were encouraged to contact the factory directly in the event such repairs were necessary.
This seemed a prescient recommendation since Sprenger’s team had no way to gauge how many examples of the 3.1 SC-L (Leistungsgesteigert or “increased power”) might be built. After all, the desire to keep the project from publication meant the motor upgrade was never an official option. As such, no option code ever existed for the 3.1. Porsche knew that certain potential SC buyers would be put off by the lack of power in the 3.0, so dealers were instructed by Ernst Bret in Sales and Customer Service to quietly mention the availability of a factory-installed power kit whenever such shoppers voiced displeasure. Thus, news of the DM 7,500 option (approximately $3,750 in 1978) was spread entirely by whispered word of mouth. That news never extended across the pond, since the 3.1 was made available first to the German market and then remaining RoW markets. It was never offered in the U.S.