BMW 320 E21
1975 - 1981
|Inline 4 SOHC|
|109 bhp at 5800 rpm|
|4 spd. man / 3 spd. auto|
Although the BMW company's reputation was built on its large saloon and sports coupe models, since the 1970's its major source of revenue has been supplied by the company's bread-and-butter family saloons.
Typical of these models was the 320 range, introduced during mid 1975. The 3-series model replaced the 1602/2002 series which for many years had proved the mainstay of BMW's production.
In appearance the 320 model was vaguely reminiscent of the larger and more expensive 5-series, a clever marketing plan which gave the car an instant glamorous image not normally associated with medium-sized saloons.
The 320 was powered by a four-cylinder single-overhead-cam-shaft 1990 cc engine which developed 109 bhp (DIN) at 5800 rpm. A more powerful version of the 320, designated the 320i, was also available.
The power produced by the 320i engine was 125 bhp (DIN) at 5700 rpm. The main reason for this power increase was that the 320i had a compression ratio of 9.3 to 1 compared with the 320's 8.0 to 1.
In addition, the 320i was fitted with a Bosch fuel-injection unit whereas the 320 made use of a single Solex twin-choke carburettor. The four-speed Getrag gearbox had the same ratios as on the previous 2002 range and also used Borg Warner synchromesh.
Automatic transmission, by means of a three-speed ZF unit, was also available. Steering was by rack-and-pinion while the front suspension was independent and used coil springs, MacPherson struts and an anti-roll bar.
The rear suspension comprised coil springs and semi-trailing wishbones. Braking was much better than on previous iterations, one of the improvments to both front and rear systems being that they had separate circuits. The front brakes were 10 inch discs, drum brakes were fitted at the rear.
The interior design marked the introduction of a new design concept, with the center console angled towards the driver. This feature has become part of BMW’s interior design philosophy for many years. As a sign of passive safety, all edges and control elements within the interior were rounded off and padded.
In all, the 3-series model was much smoother and quieter than its 1602/2002 predecessor. In addition, the steering was lighter and more precise while performance was really exceptionally good for a small 2-litre saloon. A factory authorised cabrio version was also built by Baur. To draw clear visual distinction within the new model series, the 320 models came with dual headlights, while the 316 and 318 had single round headlights.
BMW 320 Quick Specifications
Engine: Front-mounted, water-cooled straight-four. 89.0 mm (3.5 in) bore x 80 mm (3.15 in) stroke - 1990cc (121 cu. in). Maximum power (DIN) 109 bhp at 5800 rpm; maximum torque 116 lb. ft. at3700rpm. Cast-iron cylinder block and aluminium head. Compression ratio 8.1:1. 5 main bearings. 2 valves per cylinder operated via rockers by single overhead camshaft. 1 Solex 40PDSi carburettor.
Transmission: Single-dry-plate clutch and 4-speed manual gearbox. 3-speed automatic optional. Ratios (for manual) over- all, 1 st 3.76, 2nd 2.02, 3rd 1.32, 4th 1: 1. Hypoid-bevel final drive. Ratio 3.640:1.
Suspension: Front-independent by coil springs, MacPherson struts, anti-roll bar; rear, independent by coil springs, semi- trailing arms.
Steering: Rack-and-pinion. Turns from lock to lock 4.1.
Brakes: Servo-assisted discs (10.0in) front and drums (9.8 x 1.57 in) rear. Handbrake operating on rear wheels.
Wheels & Tyres: 5 in x 13 in steel. Tyres 165SR x 13.
Body/chassis: 2 door, 5-seater saloon.
Dimensions and weight: Wheelbase 8 ft 4.9 in; track- front 4 ft 5.7 in, rear-4 ft 6.2 in; length 14 ft 3.4 in; width 5 ft 3.4 in; height 4ft 6.3in; ground clearance 5.7 in; fuel tank capacity 11.4 gals; turning circle between walls 33ft 6 in. Weight 2271 lb.
Performance: Maximum speed 106 mph; Acceleration: from 0-50 mph 7.3 secs. Fuel consumption overall for both town and country driving 28.0 miles per gallon.
Models at Release: At the E21's release, three models were available: with 316 (1.6 litre), 318 (1.8 litre) and 320 (2.0 litre) versions of the BMW M10 four cylinder engine. At the 1977 Frankfurt Motor Show, BMW unveiled its new variants of the E21, featuring the new six-cylinder M20 engines. The four cylinder 320 model was replaced with the 320/6, featuring a 2.0 litre version of the M20 engine. The 323i model was introduced, featuring 2.3 litres and 143 PS (105 kW; 141 hp). The braking system was also upgraded, with the 323i featuring disc brakes on all wheels. For the 1979/80 model year, the four-cylinder models were upgraded: the 1.8 litre power unit was revised and entered the market as a 90 PS (66 kW; 89 hp) carburetor engine in the 316, while addition of Bosch K Jetronic fuel injection to the 1.8 litre engine raised the 318i to 105 PS (77 kW; 104 hp). Since there was now also room for a new entry-level model, the 315 powered by a 75 PS (55 kW; 74 hp) 1.6 litre M10 engine made its appearance in 1981.