100 cfm more with anular and downleg boosters can't beat AFR

@Mattax any idea what kind of flow restriction the annular boosters Caused in your particular case? Seems with a choke horn they take up a whole lotta space there. Do you have any data from the 750 before and after the booster change?


It depends on the booster. I’m very green on these boosters, but what I’m finding out is the better boosters are a SLIGHT CFM air reduction.

Which, comes back around to the old saying “not all airflow is good airflow”.

If a slight reduction in air flow cleans up distribution, allows less total timing (within reason...in my opinion no way will a chamber that runs at say...35 degrees will ever run at 28 degrees if everything is perfect...you may get down to 32...maybe), reduces required MJ sizing and such, then I consider that an easy thing to give up and a win.

Because of the way most engine dyno’s measure power, a booster change may not show up in anything but the BSFC number. On an inertia dyno, that lower BSFC number will translate into higher HP numbers.

On the other side of the coin, you can atomize the fuel too much and lose power right quick. A heated intake manifold, engine temps for catalytic converters and such will atomize the fuel too much and drop power.

I have at least 6 carbs that are getting annular boosters this year. It may suck hard on all of them. I hope not, because that’s going to cost me an arm and a leg.