Alvis Speed 20

Speed Twenty and 3½-litre
Speed Twenty and 3½-litre
	1935 Speed Twenty SC
Overview
Manufacturer	Alvis
Layout
Configuration	straight-six
Displacement	SA & SB 2,511 cc (153 cu in); SC & SD 2,762 cc (169 cu in); 3½-litre 3,571 cc (218 cu in);
Cylinder bore	SA to SD 73 mm (2.9 in); 3½-litre 83 mm (3.3 in);
Piston stroke	SA & SB 100 mm (3.9 in); SC & SD 110 mm (4.3 in);
Cylinder block material	4-bearing balanced crankshaft with torsional vibration damper
Cylinder head material	alloy pistons
Valvetrain	pushrod overhead valves camshaft drive by duplex chain patented multiple valve springs
Combustion
Fuel system	3 SU carburettors supplied by double petrolift hotspot and dual ignition
Fuel type	petrol
Oil system	forced lubrication to main and big end bearings, rockers and pushrods
Cooling system	water, thermostatic radiator shutters, centrifugal pump
Output
Power output	SB 95 bhp @ 4,000 rpm; 3½-litre 102 bhp @ 3,600 rpm; SA to SD 19.82 tax horsepower; 3½-litre 25.63 tax horsepower;
Chronology
Predecessor	Silver Eagle

Alvis Speed 20
Alvis Speed 20
	1933 Speed 20 SA sports 4-seater by Vanden Plas
Overview
Manufacturer	Alvis
Production	1932–36; 1165 made;
Body and chassis
Class	Mid-size
Body style	4-door sports saloon; 4-seater drop head coupé; sports 4-seater; chassis for bespoke body;
Layout	Front-engine, rear-wheel-drive
Powertrain
Engine	SA & SB 2,511 cc (153 cu in); SC & SD 2,762 cc (169 cu in); 3½-litre 3,571 cc (218 cu in); Straight-6
Transmission	4-speed manual transmission
Dimensions
Wheelbase	SA 123 in (3,124 mm); SA option 132 in (3,353 mm); SB-SD 124 in (3,150 mm); SD option 130 in (3,302 mm); 3½-litre 127 in (3,226 mm); track 56 in (1,422 mm)
Width	65 in (1,651 mm) SA ; 66.5 in (1,689 mm) SB-SD
Kerb weight	3,528 lb (1,600 kg) (4-door sports saloon)
Chronology
Predecessor	Alvis Silver Eagle
Successor	Alvis Speed 25

The Alvis Speed 20 is a British touring car that was made between late 1931 and 1936 by Alvis Car and Engineering Company in Coventry. It went through four variants coded SA to SD.

In October 1935 the Speed 20 was supplemented by a 3½-litre car initially sold alongside their Speed 20 SD and named 3½-litre SA. After their Speed 20 was dropped from their catalogue the 3½-litre car was given a shorter wheelbase and named Speed 25 SB.