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  • Writer's pictureMatteo Licata

CEM: Alfa's Forgotten Engineering Triumph

Cylinder deactivation technology is quite common in modern cars, especially those equipped with larger engines. But what if I told you that, over four decades ago, you could have bought an Alfetta that seamlessly switched on and off half its cylinders according to driving conditions?


Cleaning up

The onset of tailpipe emissions regulations in the USA during the late 1960s marked the beginning of automobile engineers' ongoing efforts to marry performance and compliance.

Even though Alfa Romeo's share of the US market was minuscule, the Portello's engineers could already see the company needed to prepare for a future of ever-more pressing regulatory demands while preserving the power and drivability its customers so much enjoyed.

Alfa Romeo's first response to US regulations was a mechanical fuel injection system produced by its Spica subsidiary. Meanwhile, work began behind the scenes with the pioneering electronic systems produced by the eponymous German supplier Bosch.

Alfa's classic twin-cam engines employed two side draught double-choke carburetors on short intake runners, which allowed a sportier intake camshaft profile and more significant overlap in the valves' timing.

However, those earliest Bosch EFI systems couldn't yet manage individual throttle bodies and therefore didn't allow Alfa's proud engineers to achieve the engine performance they were after.


Alfa's moonshot

Alfa Romeo's research and development budget could only stretch so far, though, but a public research contract that Italy's Consiglio Nazionale delle Ricerche awarded in 1979 to Fiat's research branch CRF presented an opportunity.


By becoming a subcontractor for the CRF, Alfa could tap into that budget to fund its research on electronic engine management systems and hybrid vehicle technologies.

The Alfetta's classic 1962cc inline-four twin-cam became the platform for Alfa's CEM (Controllo Elettronico Motore). It was a fully integrated electronic engine management system entirely designed in Italy by Alfa Romeo and Spica, featuring one throttle body for each cylinder and cylinder deactivation.


By running on just two cylinders at light engine loads and smoothly transitioning back to four cylinders, the Alfetta 2.0 equipped with the CEM system promised to retain the performance of the standard carbureted engine while improving drivability and fuel economy.


The theory was tested by loaning 10 Alfetta 2.0 CEM to Milanese taxi drivers for six months in 1982, during which each car clocked around 40.000 closely monitored kilometers.

The small fleet performed admirably, leading to a broader experiment involving a 1000 Alfetta 2.0 CEM for sale to actual Alfa Romeo customers.

However, that's where things began to unravel. The company estimated that, for a hypothetical production run of 10.000 Alfetta 2.0 CEM, the system increased the production cost of each engine by around 50%. And that's because Alfa Romeo couldn't count on the economies of scale enjoyed by a company like Bosch, which supplied nearly everyone in the business, including Alfa itself.

994 Alfetta 2.0 CEM were ultimately built, and quite a few still survive in enthusiasts' hands. But the only Alfa Romeo model equipped with the CEM to ever enter regular series production was the Alfa 90 2.0 6V Iniezione, produced between 1985 and 1987 and fitted with a 1996cc version of the "Busso" V6 employing a simplified system without the cylinder deactivation function.

Following Fiat's takeover of Alfa Romeo in November 1986, profitability soon took precedence over costly technical feats, and the CEM was quietly consigned to history.


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