1915 |
American Grand Prize (sixth), regulations restricted engine capacity to 450 ci - 7.375-liter.
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1915 |
Vanderbilt Cup Race regulations restricted engine capacity to 450 cubic inches - 7.375-liter.
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1915 |
Indianapolis 500 maximum engine capacity of 300 cubic inches - 4.917-liter. No more than three cars of the same make could start in the race.
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1916 |
Indianapolis 500 maximum engine displacement of 300 cubic inches - 4.917-liter.
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1916 |
Vanderbilt Cup Race regulations restricted engine capacity to 450 cubic inches - 7.375-liter.
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1916 |
American Grand Prize (seventh), regulations restricted engine capacity to 450 ci - 7.375-liter.
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1919-1920 | The Manufacturers’ Association in France decided not to support the French Grand Prix in 1919 and 1920.
Likewise, the Association of British Automobile Manufacturers also decided against racing in those years
in view of the industry's situation after the war. Without a Grand Prix Formula in place, races were run to
Formula Libre and had a doubtful Grand Prix stature.
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1919 |
Indianapolis 500 maximum engine displacement of 300 cubic inches - 4.917-liter.
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1919 |
Targa Florio regulations were for cars with 4-cyl. engines with a bore of 60 and 130 mm, divided into
7 categories, also allowing 6, 8 and 12 cylinder engines, provided that the bore was correspondingly
smaller to assure that the power of the 4-cylinder engines was not exceeded. 1. category: 4-cyl. engines
with 60-70 mm bore, 6-cyl. with 52-56 mm bore; 2. category: 4-cyl. with 71-80 mm bore, 6-cyl. with 57-63
mm bore, 8-cyl. with 51-55 mm bore; 3. category: 4-cyl. 81-90 mm, 6-cyl. 64-72 mm, 8-cyl. 56-62 mm; 4.
category: 4-cyl. 91-100mm, 6-cyl. 73-83 mm, 8-cyl. 63-70 mm, 12-cyl. 53-60 mm; 5. category: 4-cyl. 101-
110 mm, 6-cyl. 84-94 mm, 8-cyl. 71-78 mm, 12-cyl. 61-68 mm; 6. category: 4-cyl. 111-120 mm, 6-cyl. 95-
105 mm, 8-cyl. 79-87 mm, 12-cyl. 69-77 mm; 7. category: 4-cyl. 121-130 mm, 6-cyl. 106-117 mm, 8-cyl.
88-98 mm, 12-cyl. 78-88 mm bore.
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1920 |
No formula existed in Europe. At the Indianapolis 500 mile race the 3-liter - 183 ci maximum
engine capacity was introduced, which had already been planned for Europe before the war.
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1920 |
Targa Florio regulations were only for cars with production chassis as was delivered per catalog to
the public. The cars were divided by engine capacity into 7 categories, namely for cars with an engine
capacity of up to 1.5-liter, 2-liter, 2.5-liter, 3-liter, 4-liter, 5-liter and more than 5-liter.
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1921 |
3-liter maximum engine capacity formula, already applied in America, was now adopted for grand
prix racing plus a minimum weight limit of 800 kg - 1763 lb was added. The chassis' of that time were
not in par with the highly developed engines, therefore a reduction for 1922 was envisaged.
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1921 |
Targa Florio regulations specified racing cars without restriction of engine capacity and production
cars divided into four categories according to engine capacity up to 2-liter, 3-liter, 4.5-liter and
more than 4.5-liter. As production car was understood only a car described in the normal factory sales
catalogues. Further engine stroke and bore, length and width of chassis, lay-out of the valves, dimension and
shape of radiator, lights, position of gearbox and control levers, diameter and stroke of valves, pistons and
connecting rods had to conform with the production type. The bodywork was free under condition that it
had two seats for competitors; the generator dynamo was not removed, including headlamps and lights.
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1922 |
On December 7, 1922 at their Annual General Meeting in London the A.I.A.C.R. (Association Internationale
des Automobile Clubs Reconnus) finally formed an international subcommittee, the C.S.I. (Commission
Sportive Internationale) to look after all aspects of motor racing, draw up regulations and introduce the rules
for international grand prix racing. From 1904 to 1922 the ACF continiously had persisted that only they
alone were to undertake the establishment of the international race formulas and sporting rules. As members
of the CSI were elected representatives from the Automobile Clubs of France, Italy, Great Britain, America,
Belgium, Austria and Spain. The CSI convened for the first time on this same day and elected as President
the Belgian René de Knyff, who exercised this post until 1946. The French Augustin Pérouse succeeded him.
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1922-1924 |
2-liter formula; maximum engine capacity of 2.0-liter; minimum weight of 650 kg - 1433 lb; the end
of car was not to extend beyond the center of rear axle by more than 150 cm. The weight of driver and his
mechanic had to have a total weight of at least 120 kg - 264 lb. With the introduction of the supercharger,
the 2-liter cars soon proved to be too fast and dangerous, reaching now top speeds in excess of 220 km/h.
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1922 |
Targa Florio regulations specified racing cars without restriction of engine capacity and production
cars divided into six categories according to engine capacity up to 1.1-liter, 1.5-liter, 2-liter, 3-liter,
4.5-liter and over 4.5-liter. As production car was understood only a car described in the normal factory
sales catalogues. As such it had to be for sale and at least 50 chassis had to be produced by the factory.
Further engine stroke and bore, also the lay-out of the valves had to conform with the production type.
Competitors had to strip cylinders of engines for inspection. If the production car did not conform with the
characteristics required, it was classified as racing car. Entry fee for each car was 2000 lires. The maximum
allowable time for classification was ten hours. Drivers and riding mechanics could be changed during the race,
however only at the end of a lap, in presence of a commission of drivers and mechanics, which had to be
predetermined beforehand.
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1923 |
On November 2, 1923, the International Calendar Congress took place in Paris to determine dates for the
most important races, followed the next day by the A.I.A.C.R. meeting. In 1923, C.S.I. member countries
were the same as the year before: America, Austria, Belgium, England, France and Italy. |
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1923 |
Indianapolis 500 rules reduced engine size from 183 to 122 cubic inch , to match the 2.0-liter GP
formula, then in effect. Indianapolis became part of the manufacturers world championship from 1925 on.
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1923 |
Targa Florio regulations specified only engine capacity for six categories: up to 1.1-liter, 1.5-liter,
2-liter, 3-liter, 4.5-liter and over 4.5-liter. A category for racing cars was not given only engine capacity
was stated.
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1924 |
Targa Florio regulations divided the cars into seven categories: up to 750 cc, 751-1100 cc, 1101-1500
cc, 1501-2000 cc, 2001-3000 cc, 3001-4500 cc and over 4500 cc. Entry fee for each car was 1000 lire and
1500 lire for both races, the Targa and Coppa Florio. Each manufacturer could enter up to 5 cars.
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1925 |
2-liter formula; maximum engine capacity of 2.0-liter. Riding mechanics barred at the Grandes
Épreuves, however, this rule was not strictly applied at lesser events. Driving mirror was for the first time
obligatory as was the now empty mechanic's seat. Minimum empty weight not less than 650 kg - 1433 lb.
Minimum body width 80 cm - 31.5 in. Car repair and replenishment restricted to driver and one mechanic.
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1925 |
Targa Florio regulations divided cars into 5 categories: up to 1100 cc, 1500 cc, 2000 cc, 3000 cc and
over 3000 cc. Each car had to be occupied by two persons sitting next to each other of no less than 120 kg.
Driver and riding mechanic could be exchanged during the race with a beforehand named driver and riding
mechanic but only at the end of a lap in presence of a commissioner but substitutes had to be licensed.
The licensed mechanic had no right to drive. Classified in each category were only those who completed the
race within one hour of the first classified and only within a maximum of 10 hours. Entry fee for each car
was 1000 lires per race and 1500 lires for both, the Targa and Coppa Florio.
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1925 |
First World Championship for manufacturers was held in 1925 and set up annually until 1930. Only the
first three took place, the others failed AIACR approval because of rules noncompliance. Following WW I,
German cars and drivers were excluded from GP racing in France, Belgium and England. In May 1925, the
German Automobile Club was re-admitted into the A.I.A.C.R. and in November 1925, also into the CSI.
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1926 |
1.5-liter formula, maximum engine capacity. Regulations for the Indianapolis 500 cars changed
from 122 cubic inches to 91.5, matching the 1.5-liter Grand Prix Formula. Minimum weight of 600
kg - 1322 lb; minimum body width of 80 cm - 31.5 in. Still two seats required. But cars still reached 200
km/h. Interest in the formula declined greatly because the companies who as a rule built only large engines,
did not want to occupy themselves with the study of 1,5-liter engines. Thus a change in 1928 was planned.
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1926 |
Indianapolis 500 rules reduced engine size from 122 to 91.5 cubic inch , to match the 1.5-liter GP
Formula, changed for 1925. Indianapolis remained part of the world championship until 1930.
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1926 |
Targa Florio regulations were for cars divided into four categories: up to 1100 cc, 1500 cc, 2000 cc
and over 2000 cc. Each car had to have two seats next to each other, minimum weight of driver and
mechanic together of 120 kg. If the mechanic's seat remained unoccupied, a ballast of 80 kg had to be carried
along. Driver and mechanic could exchange each other but only at the end of each lap. Entry fee was 1000
lire per car. To be classified all cars had to complete the 4-lap race within 10 hours except 1100cc category
cars, which could not exceed a maximum time of 8 hours with a racing distance of only 3 laps.
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1927 |
1.5-liter formula; minimum weight limit now increased to 700 kg - 1543 lb. Two seats remain
mandatory but at the same time single-seater cars were allowed provided the seat had a minimum
width of 80 cm - 31.5 in and a minimum height of 25 cm - 9.8 in. Superchargers were allowed.
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1927 |
Targa Florio regulations were for racing cars divided into three categories: up to 1100 cc, 1500 cc,
and over 1500 cc.
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1928 |
Formula Libre; no engine capacity limit; car weights between 550 and 750kg - 1212 and 1653 lb.
Minimum race distance 600 km - 372 mi (only used for Italian Grand Pix).
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1928 |
Targa Florio regulations were for racing cars divided into five categories: up to 1100 cc, 1500 cc,
2000 cc, 3000 cc and 5000 cc.
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1928-1929 | Some manufacturers lost interest and withdrew, reducing the glamour of grand prix racing. The formula was
unpopular and some races were held for sports cars. Bugatti and Maserati sold grand prix racing cars. |
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