2012 carb shootout

[vector1]

they put a limit on the a/f ratio in consideration of the engine owner, who donated it for the competition.

david vizard was one of the judges, and he said some of the bsfc figures were in the .29 range.

here is their method of scoring via david vizard:



The dyno load is equivalent to the weight of a NASCAR Sprint Cup car (about 3400lbs) What we do is to time how long it takes to accelerate this mass from 5000 rpm to 8000 rpm .

For instance if it took 4 seconds with the BLP baseline carb that we use to generate the ‘bogey’ number we would have 3000 (that’s the difference between 5000 and 8000) divided by 4. The bogey number in this case being 3000/4 = 750 or 750 rpm/sec average acceleration rate.

Because the contestants are so close we want to minimize the effects of weather changes to a minimum. What we do here is to run a baseline with the BLP carb then run two contestants then another baseline. The results are the average acceleration rate of the contestants entry compared to the adjacent baseline.

Let’s take the last test we did. That was Holley’s entry. Their carb delivered an average rpm/sec acceleration rate of 753.1 rpm/sec and directly after that the baseline BLP carb delivered a 753.8 rpm/sec. Who ever has the best ratio between these two numbers is the winner!! Now does all that make sense?
DV