User:Cloverleaf II/Alfa Romeo Transaxle platform

The Alfa Romeo Transaxle platform was a front-engine, rear-wheel-drive automobile platform developed by Italian car manufacturer Alfa Romeo, which debuted on the 1972 Alfa Romeo Alfetta and later underpinned almost every Alfa Romeo rear-wheel drive car introduced in the following two decades.

History
By the late 1960s Alfa Romeo designers were starting to look into a successor for the Giulia. Development of the car that would became known as the Alfetta started in 1967. According to Giuseppe Busso, director and chief designer at Alfa Romeo, the new rear suspension layout was chosen in June 1967 after pitching three cars in a testing session on the hill roads around the Futa Pass: a pair of V8-engined GTA development mules each fitted with different independent rear suspension types, and the Alfa Romeo 2000 Sportiva, taken out of storage after 10 years for the occasion; in the end, the peculiar De Dion tube layout of the venerable 2000 Sportiva was preferred both by Busso and by driver Consalvo Sanesi.

Description
Body structure was unibody, constructed of stamped steel panels. The engine was placed longitudinally between the front wheels, while the transmission was placed at the back in the transaxle layout.

Front suspension was of the double wishbone type. The lower link was an A-arm, while the upper one consisted of a transverse link and one tubular radius rod, adjustable for caster angle. The elastic elements were longitudinal torsion bars, in place of the usual coil springs, actuated by the innermost side of the lower A-arms and connected to the chassis by a single transverse crossbeam. Slanted hydraulic dampers passed though a hole in the upper suspension link. An anti-roll bar was fitted.

Rear suspension was of the De Dion tube type. The axle was shaped like an isosceles triangle around the transaxle unit. Two tubular conical torque arms made up the triangle's legs and, linked to the body by a crossmember, located the axle longitudinally; the third side in the triangle was the De Dion tube. A Watt's link on the rear part of the tube located transversally the axle. Coil springs, hydraulic dampers and an anti-roll bar completed the setup.

Clutch, 5-speed gearbox and differential were all grouped togeter in a single transaxle unit. Rear disk brakes were inboard, the callipers bolted to the differential. The transaxle was supported at the front by the same crossbeam to which the De Dion tube was attached, and by a bushing at the rear of the differential housing. Steering was by rack and pinion.

2510 mm wheelbase

 * 1972–1984 Alfa Romeo Alfetta
 * 1977–1985 Alfa Romeo Giulietta
 * 1984–1987 Alfa Romeo 90
 * 1985–1992 Alfa Romeo 75

2400 mm wheelbase

 * 1974–1987 Alfa Romeo Alfetta GT, Alfetta GTV, GTV and GTV6

Alfa Romeo SZ and RZ
The last transaxle Alfa Romeos were the 1989 and 1990 Zagato-designed SZ and RZ specialty sports cars. They had a composite body built on the 75 platform, to which several changes had been made. Coaxial coil springs and dampers with hydraulic lifters were employed on both axles, replacing the torsion bars at the front and the separate springs/dampers at the rear. This entailed the adoption of a different triangular beam, designed to give the rear wheels negative camber angle.