In the early 1960s Rolf Mellde, Per Gillbrand and Karl Rosenqvist began work on a new 1.2 L inline four for the upcoming Saab 99.

[4]: 47, 48  A consequence of this is that the "front"-mounted water pump would be facing the firewall/bulkhead and be inaccessible, prompting it to be relocated to the top of the cylinder block.

While the B engine carried features like bore centers and bearings over from the original Triumph design, it was a substantial redesign.

Other changes from the Triumph slant-four included a new cylinder head with bigger valves, enlarged ports, a new combustion chamber shape, and a camshaft assembly redesigned for better lubrication.

[6] Intake systems for the Saab 99 had included fuel injected versions from as early as the 1970 model year, and this continued with the B engine, along with both single- and dual-carburettor setups.

The early B engine was one of two (the other being the Honda CVCC) that were able to meet the stringent emission requirements set by the state of California for 1975 without resorting to a catalytic converter.

A key member of the team that developed the Turbo engine was Per Gillbrand, who earned the nicknames Turbo-pelle (Turbo-Pete) in Swedish and Mr.

[9][10] Mellde was also on the development team, and he and Gillbrand were also joined by Bengt Gadfelt, who came to them from Scania where he worked on turbocharging Saab-Scania trucks, and Englishman Geoffrey Kershaw, who had apprenticed at Rolls-Royce and would go on to found Turbo-Technics Ltd.[1] Saab's emphasis was on torque, rather than maximum power.

An alternative-fuel version of the Saab 99 GL called the Petro was developed by the joint venture Saab-Valmet and built at the Valmet factory in Uusikaupunki.

[15] 1975-1981 Driver Stig Blomqvist won the 1976 Belgian Rally Boucles de Spa in a specially prepared 16-valve Saab 99.