{{EngvarB|date=February 2018}} {{Use dmy dates|date=February 2018}} {{Infobox automobile |name = Alvis Speed 20 |image = 1933 Alvis Speed 20 SA IMG 2773 - Flickr - nemor2.jpg |caption = 1933 Speed 20 SA sports 4-seater by Vanden Plas |aka= |manufacturer = Alvis<ref name=TT45960>The Olympia Show. ''The Times'', Thursday, 22 Oct 1931; pg. 18; Issue 45960</ref> |production = {{ubl |1932–36|1165 made<ref name=AZ1930>{{cite book |last1=Sedgwick |first1=Michael |last2=Gillies |first2=Mark |title=A-Z of Cars of the 1930s |year=1993 |publisher=Bay View Books |isbn=978-1-870979-38-2}}</ref>}} |wheelbase = {{ubl |SA {{convert|123|in|mm|0|abbr=on}}|SA option {{convert|132|in|mm|0|abbr=on}}<ref name=TT45960/>|SB-SD {{convert|124|in|mm|0|abbr=on}}<ref name=TT46560>Cars Of 1934. ''The Times'', Wednesday, 27 Sep 1933; pg. 5; Issue 46560</ref>|SD option {{convert|130|in|mm|0|abbr=on}}<ref name=BritishCars>{{cite book |last1=Culshaw |first1=David |last2=Horrobin |first2=Peter |title=Complete Catalogue of British Cars |year=1974 |publisher=Macmillan |isbn=978-0-333-16689-5}}</ref>|3½-litre {{convert|127|in|mm|0|abbr=on}}<ref name=TT47201>The Motor Show. ''The Times'', Tuesday, 22 Oct 1935; pg. 9; Issue 47201</ref> }} track {{convert|56|in|mm|0|abbr=on}}<ref name=TT45960/> |length = |width = {{convert|65|in|mm|0|abbr=on}} SA <br /> {{convert|66.5|in|mm|0|abbr=on}} SB-SD<ref name=BritishCars/> |successor = Alvis Speed 25 |predecessor = Alvis Silver Eagle |class = Mid-size |body_style = {{ubl |4-door sports saloon|4-seater drop head coupé|sports 4-seater|chassis for bespoke body}} |layout = Front-engine, rear-wheel-drive |engine = {{ubl | SA & SB {{convert|2511|cc|cuin|0|abbr=on}}<ref name=TT45960/> | SC & SD {{convert|2762|cc|cuin|0|abbr=on}}<ref name=TT46858>Cars Of 1935. ''The Times'', Thursday, 13 Sep 1934; pg. 8; Issue 46858. </ref>|3½-litre {{convert|3571|cc|cuin|0|abbr=on}}<ref name=TT47185/> }} Straight-6<ref name=TT45960/> |transmission = 4-speed manual transmission |weight = {{convert|3528|lb|kg|0|abbr=on}} (4-door sports saloon)<ref name=TT46718/> | sp = uk }} {{Infobox automobile engine | name = Speed Twenty and 3½-litre | image = Alvis Speed 20 SC Lancefield Drophead Coupe (8514289680).jpg | caption = 1935 Speed Twenty SC | manufacturer = Alvis | aka = | production = | predecessor = Silver Eagle<ref name=TT45960/> | successor = | configuration = straight-six<ref name=TT45960/> | displacement = {{ubl | SA & SB {{convert|2511|cc|cuin|0|abbr=on}}<ref name=TT45960/> | SC & SD {{convert|2762|cc|cuin|0|abbr=on}}<ref name=TT46858/>|3½-litre {{convert|3571|cc|cuin|0|abbr=on}}<ref name=TT47185/>}} | bore = {{ubl |SA to SD {{convert|73|mm|in|abbr=on}}<ref name=TT45960/>|3½-litre {{convert|83|mm|in|abbr=on}}}} | stroke = {{ubl |SA & SB {{convert|100|mm|in|abbr=on}}<ref name=TT45960/>|SC & SD {{convert|110|mm|in|abbr=on}}<ref name=TT46858/>}} | block = 4-bearing balanced crankshaft with torsional vibration damper<ref name=TT46560/> | head = alloy pistons<ref name=TT45960/> | valvetrain = pushrod overhead valves<ref name=TT45960/> camshaft drive by duplex chain<ref name=TT46560/> patented multiple valve springs | compression = | supercharger = | turbocharger = | fuelsystem = 3 SU carburettors supplied by double petrolift<ref name=TT45960/> hotspot and dual ignition<ref name=TT46560/> | management = | fueltype = petrol | oilsystem = forced lubrication to main and big end bearings, rockers and pushrods<ref name=TT46560/> | coolingsystem = water, thermostatic radiator shutters, centrifugal pump<ref name=TT45960/> | power = {{ubl |SB 95 bhp @ 4,000 rpm<ref name=TT46718/>|3½-litre 102 bhp @ 3,600 rpm<ref name=BritishCars/>|SA to SD 19.82 tax horsepower|3½-litre 25.63 tax horsepower<ref name=TT47201/>}} | specpower = | torque = | length = | width = | height = | diameter = | weight = }} 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.
==Speed 20 SA== {| |The engine for the Speed 20 was a heavily modified version of the one used in the preceding Silver Eagle cars, producing {{convert|87|bhp|abbr=on}}.<ref name=AZ1930/> Triple HV4 type SU carburettors were fitted. As before the engine and clutch unit sat on flexible conical rubber mountings in a system used by Alvis from 1925. The chassis was new and lowered by making it a "double drop" type where the side rails go over the front and rear axles. A centralised lubrication system was fitted allowing oil to be provided to moving suspension parts through a maze of pipework. Both front and rear suspension used half-elliptic leaf springs and the self-servo brakes, with {{convert|14|in|mm|0|abbr=on}} drums, were mechanically operated. The four-speed manual gearbox was mounted in-unit with the engine.<ref name=TT45960/> |thumb|1932 Sports tourer thumb|1933 Sports tourer |} The car could be fitted with a variety of coachwork. Standard bodies were a four-door sports saloon from coachbuilders Charlesworth, a four-seater sports coupé or four-door tourer by Cross & Ellis, but some cars were supplied in chassis form and carried bodies by coachbuilders such as Vanden Plas.<ref name=TT46560/> The 4-speed gearbox had constant mesh on the top two gears.. It used a single plate clutch, central change lever, open tubular propeller shaft with metal joints (arranged in a straight line), and a spiral bevel fully floating back axle.<ref name=TT45960/>
Approximately 400 of the SA cars were made.
==Speed 20 SB== The SB launched at the October 1933 London Motor Show had a new cruciform braced chassis, slightly longer at {{convert|124|in|mm|0|abbr=on}}, with independent front suspension using a single transverse leaf spring with a long solid anchorage in the centre.<ref>Specifications, Latest British Products, Models For 1935, Cars and Commercial Vehicles. ''The Times'', Tuesday, 2 Apr 1935; pg. 63; Issue 47028. </ref> Steering was improved using new designs employed for racing Alvis cars since 1925. Road shocks were not transmitted from one wheel to the other nor did they affect the steering wheel and the gyroscopic effect was eliminated. Rear springs damped by Hartford Telecontrol dampers are long and underslung. The engine remained the same but the new all-silent gearbox, the first of its type, had synchromesh on all gears and was mounted separately from the engine.<ref name=TT46718/> A built-in jacking system was fitted as standard.<ref name=TT46560/>
As with the SA, a wide range of bodies were fitted to the cars. Large Lucas {{convert|12|in|mm|0|abbr=on}} P100 headlamps became standard, adding to the sporting appearance of the car.<ref name=TT46560/> {| |[[File:Alvis Speed Twenty - Flickr - mick - Lumix.jpg|thumb|Speed 20 standard 4-door sports saloon by Charlesworth]] |[[File:1934 Alvis Speed 20 SB "flat-back" 2-door saloon by Vanden Plas, rear right.jpg|thumb|1934 Speed 20 SB "flat-back" two-door saloon by Vanden Plas]] |}
===Road test=== ''The Times'' motoring correspondent tested and after describing its technical features in detail reviewed the car. Salient comments have been summarised as follows. The four-seater saloon was described as "distinctly fast in acceleration and speed" with a comfortable body such that a passer-by looks twice at it. A third person could be squeezed into the back seat. The four windows in the four doors allowed a good view all round. It was noted that each front wheel was independently steered and sprung in the manner introduced on the Alvis Crested Eagle and used on Alvis's racing cars since 1925, the aim being to provide good directional stability, road-holding and comfort.<ref name=TT46718>''The Times'', Tuesday, 3 April 1934; pg. 3; Issue 46718. </ref>
The steering and suspension was a star feature, the steering action exceptionally steady and light. The car does not heel or roll and there is little wheel bounce. The best speeds on second and third gears were 48 and 68 mph, 90 mph should be possible in top. Providing on the road such rapid acceleration and high rates the engine ran fairly quietly and with smoothness yet displaying exuberant spirits. The action of clutch and new gear change was pleasing.<ref name=TT46718/> {| |[[File:1934 Alvis Speed 20 Vanden Plas Saloon 2762cc 20hp.jpg|thumb|1934 Speed 20 SC fixed head coupé by Vanden Plas]] |[[File:1935 Alvis Speed 20 SC Mayfair 9682973412.jpg|thumb|1935 Speed 20 SC sports saloon by Mayfair]] |}
==Speed 20 SC== For 1935 the engine grew to 2762 cc by increasing the stroke to {{cvt|110|mm|in|2}} and the range designation became SC. Modifications were also made to the complex steering gear, and the front damping was improved. Twin electric fuel pumps were provided. At the rear the chassis was stiffened by having side members above and below the axle.<ref name=TT46858/> {| |thumb|Speed 20 SC instrument panel |thumb|Speed 20 SC |}
==Speed 20 SD== The final SD version for 1936 was similar to the SC but had a larger fuel tank and slightly wider bodywork. A {{convert|130|in|mm|0|abbr=on}} wheelbase version became an option. {| |[[File:1936 Alvis Speed Twenty 10135340186.jpg|thumb|left|1936 Speed 20 SD 4-dr sports saloon<br>by Lancefield]] |right|thumb|1936 Speed 20 with open two-seater body |}
==3½-litre engine== [[File:Alvis 3.5 litre 1935 Castle Hedingham 2008.JPG|thumb|1936 3½-litre drophead coupé<br>by Charlesworth]] As with many cars of the time, bodies were getting more luxurious and hence heavier. Five weeks after their 30 August 1935 announcement of minor improvements to their Speed 20 Alvis announced a new additional 3½-litre 102hp engine fed by triple SU carburettors<ref name=TT47185>Cars Of 1936. ''The Times'', Thursday, 3 Oct 1935; pg. 10; Issue 47185</ref><ref name=TT47201/> naming it 3½-litre SA. Twelve months later, given a strengthened engine with seven main bearings, it was renamed Speed 25.<ref>Cars Of 1937. ''The Times'', Wednesday, 26 Aug 1936; pg. 8; Issue 47463</ref>
==References== {{reflist}}
==External links== {{commons category}} * [http://www.alvisoc.org/ Alvis Cars Owners Club website]
Speed 20 Category:Cars introduced in 1932