SRX700guy said:
"Whats your brake specific?"...What does this foreign language mean??
I would suggest the quote refers to "Brake Specific Fuel Consumption"[BSFC]
it is measured in and equals "pounds of fuel per hour per horsepower" [the lower the number the leaner the fuel/air ratio is]
.70 and higher is safe spec for pump gas
[Most stock 2 strokes are factory jetted for high .70s and maybe into the low .80s]
.60 - .69 requires 92+ octane fuel to resist detonation during sustained high speed ops
.55 - .59 allows short full throttle runs on 92 octane fuel for longer runs 100+ octane is needed
.50 - .54 is OK for drag racing on 100+ octane fuel
.49 + lower...twilight zone...drag race only 110+ octane fuel
Of course a lot of variables come into play that effect optimum BSFC:
-expansion chamber design, especially stinger dimensions
-cylinder head cooling capability
-cylinder head squish clearance, widths and angles
-compression ratios
-ect
In my experience most engines make the most drag race surviveable power in the low .60s
JM.02c...Bob