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22 Apr 2010, 11:33 (Ref:2677806) | #1 | ||
Racer
Join Date: Jan 2002
Posts: 245
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Formula 3 71-73, Restrictor size
Does anyone know the correct restrictor bore for a 73 car ?
In some articles 23 mm. is mentioned, and in some 24 mm. And where is the documentation? |
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22 Apr 2010, 12:18 (Ref:2677824) | #2 | |
Veteran
Join Date: Apr 2002
Posts: 9,710
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so lets say thats an inch in old money
actually if you add tolerances over time (well known preppers calculation) and App K 'growth' you'll probably get nearer 30mm with a little translation consideration too! |
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22 Apr 2010, 13:39 (Ref:2677862) | #3 | ||
Veteran
Join Date: Jul 2005
Posts: 511
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21.5 mm (1600 cc). It can be found in the regulations for CF3.
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22 Apr 2010, 14:11 (Ref:2677874) | #4 | ||
Veteran
Join Date: Oct 2005
Posts: 1,272
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From memory, F3 restrictor sizes were increased after the first season in 1971, so if the two sizes you have are correct, then a 1973 car would me 24mm, but Marcus' research would suggest otherwise...
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22 Apr 2010, 17:05 (Ref:2677942) | #5 | ||
Racer
Join Date: Jan 2002
Posts: 245
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That is also what I can read, but some people points out, that a 1971 car cannot run with 24 mm. bore today, but if a 1971 car was entered in 1973, then it must have been legal with a 24 mm. bore, despite being another vintage.
Is that not correct? |
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23 Apr 2010, 14:27 (Ref:2678468) | #6 | ||
Veteran
Join Date: Jul 2005
Posts: 511
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My "research" only went as far as reading the CF3 regulations, from the HSCC website!
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25 Apr 2010, 14:57 (Ref:2679391) | #7 | ||
Veteran
Join Date: Jul 2005
Posts: 511
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Further research (my 1970 "Yellow Book") shows that the 1600 F3 was to start in 1971 with 20 mm restrictor and the FIA were to have the option to change it after the first season giving less than the normal 2 year notice - so presumably it was then changed to 21.5 mm. It is definitely not more than 21.5 mm for a 1973 car.
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25 Apr 2010, 16:45 (Ref:2679436) | #8 | ||
Racer
Join Date: Jan 2002
Posts: 245
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Ohh dear.
I know some people who will have to make last minute adjustment, if that is the bore that will be allowed. |
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