Saab Sonett MK II 97
|Also called||Saab 97|
|Predecessor||Saab Sonett I|
|Successor||Saab Sonett III|
|Engine||841 cc Saab two-stroke I3 1,498 cc Ford Taunus V4 engine|
In the early 1960s, Björn Karlström, an aircraft and automotive illustrator, and Walter Kern, an engineer at Massachusetts Institute of Technology, independently suggested a two-seat roadster with Saab components and a two-stroke engine. Two prototypes were developed: the Saab MFI13 by Malmö Flygindustri, and the Saab Catherina by Sixten Sason.
After some modifications, the MFI13 was put into limited production (28 units) in 1966 as the Sonett II, manufactured at the Aktiebolaget Svenska Järnvägsverkstäderna (ASJ) in Arlöv. Inside Saab, it was designated model 97. A further 230 units were assembled in 1967, but as the two-stroke engine became increasingly uncompetitive in the US market, a switch to the Ford Taunus V4 engine was made in the middle of the 1967 production year, and the model was renamed the Sonett V4. Apart from the engine and related drivetrain, the Sonett II and Sonett V4 share a high percentage of components. Approximately 50 percent of the Sonett II production has survived, preserved or maintained by museums, collectors, and race enthusiasts.
Like the Sonett I prototype, the Sonett II fiberglass body was bolted to a box-type chassis with an added roll-bar to support the hard top. The entire front hood section hinged forward to allow easy access to the engine, transmission, and front suspension. Equipped with a three-cylinder, two-stroke engine generating 60 horsepower (45 kW), the Sonett II achieved 0 to 100 km/h (0–62 mph) time of 12.5 seconds, with a top speed of 150 km/h (93 mph).
Designed as a race car, the Sonett II competed successfully against other small European roadsters, including the Austin-Healey Sprite and Triumph Spitfire, in Sports Car Club of America (SCCA) races of the period. Due to low production volume, Sonett IIs were disqualified from certain competitions. By 1967, the two-stroke engine failed to meet US emission control standards. In 2011 a two-stroke Sonett II achieved 109 miles per hour (175 km/h) at the Bonneville Salt Flats.
The Škoda-engined ÚVMV 1100 GT was based on the Sonett II.
Saab Sonett Sonett V4
When Saab started using the V4 engine in their 95, 96, and Monte Carlo models, an upgrade for the low-volume Sonett II became economically feasible. The Sonett V4 was introduced with a 1500 cc Ford V4 engine in the middle of the 1967 model year. A new "bulge" hood, designed by Gunnar A. Sjögren, was required to clear the larger V4 WWMA engine, with a slight right offset to avoid obstructing the driver's view. This unbalanced hood shape, criticized by both the automotive press and within Saab itself, contributed to the motivation for the 1970 Sonett III redesign.
The Ford V4 engine produced 65 horsepower (48 kW), and—combined with the car's lightweight chassis and fiberglass construction—allowed the V4 model to accelerate from 0 to 100 km/h (0 to 62 mph) in 12.5 seconds, with a top speed of 160 km/h (99 mph).
Following the low-volume 1966–67 Sonett IIs, Saab ramped up Sonett V4 production to meet minimum SCCA requirements, assembling 70 units in the 1967 transition year, 900 units in 1968, and 640 units in the final 1969 production year—a total of 1,610 Sonett V4 vehicles.
While the Sonett V4 was assembled in Sweden, nearly the entire production was exported to the United States, with a Manufacturer's Suggested Retail Price of between US$3,200 and US$3,800 ($20,033 to $23,790 in today's dollars). In addition to its unusual fiberglass body, the Sonett V4 featured advanced safety features for its day, including a roll bar, three-point seat belts, and high-back bucket seats to protect against whiplash injury. Sonett V4s also sported a few oddities compared to standard American sports cars like GM's Corvette, such as front wheel drive; a freewheeling clutch that disengaged automatically whenever the engine speed fell below a certain threshold (that is, the accelerator pedal was no longer pressed); and a column-mounted shifter, rather than a typical floor-mounted shifter.
In spite of lackluster Saab marketing, unusual features, and quirky design, the Sonett V4 found a niche market in the US, propelled by the outstanding SCCA racing performances of the Sonett II. Its primary competitors were British roadsters, including the MG Midget and MG MGB, the Triumph TR5, the TVR Grantura, the Austin-Healey Mark IV, and the early AC Cobra.
The Clear Air Act of 1970 forced engineering modifications to the Ford V4 emission control system that were difficult to reconcile with the Sonett II/V4 body style. This regulation, along with earlier criticism of the bulge hood, led to the Sonett III redesign.