Compression: My Bugeye 948 +40 overbore, 13:1 compression race motor
requires at least 100 octane- happier when running on higher octane gas
(Turbo Blue or C12). Timing is set at 30 degrees, rev limit is 8,500, Aldon
race distributor and Pertronix, two race modified 1.25 su carbs. Plugs are
NGK B8ES. Horsepower 90 hp. Would never consider even trying to run such a
high compression engine on the street, even it it were legal to use race
gas. Way too "peaky" for street use.
Lotus Seven Twin Cam- 1600 cc "rally spec" engine, + 20 bore, compression
10:1, 152 hp at 7,200, rev limit 8,000, Lucas 43 distributor and Pertronix.
Four Weber DCOEs. 35 degrees at 5,500 revs. This was supposed to run on
premium unleaded street gas- but it sure does not like it, even our best 91
octane "Chevron with Techron" stuff. Much happier on C12 race gas. We cannot
get 93 octane in CA, and by the way - I paid $2.39 per gallon for regular
unleaded fuel yesterday!
For the street, I am sure Vizard and others are right- don't go over 9:1 CR.
By the way, Vizard writes that unless you are going over 14:1 CR, there is
no need for using any gas over 100 to 105 RON.
Calculating chamber volume: Find and read David Vizard's book "Tuning BL A
series Engine" - in particular pages 210 and 212 (in part 3 of cylinder
heads). That book is incredibly useful for anyone considering
engine/carbs/exhaust modifications.
Jacques Le Clainche in San Diego
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