Ken, so you are verifying that you lost power when you went from two 51mm bores to two 48mm bores? (51mm = ~13.11 sq in; 48mm = ~11.21 sq in; so a 48mm bore is ~ 15% smaller than a 51mm bore). Did you go with the smaller bores to improve idle?
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Hp don't mean anything as its all in CFM and at that time tne biggest they offered was 350 CFM which will work fine on the big lunged ancient airplane motors but we need free high flowing carburetors, about 650 to 700 CFM is about right.
I'm not following you here. Why is 180 HP more CFM for us than for an O-360? I just sent them a question to see what the bore diameter is on the top 3 sizes they list.
I did notice that there was a FAQ on the Ellison page that says they don't recommend auto fuel, since it could damage components in the TBI. I'm not sure how much this is real, vs CYA. Ellison doesn't seem all that much in favor of auto engine conversions in the first place.
Rusty (already talked to Van's once today, danger, danger)
Look at the crude intake manifold on a Lycosoris, it don't have any CFM ether as they just rely on the big slow moving piston to suck like hell to get the air in, very crude !!!
I am currently running a 48 Weber, I did have a 51 Weber and there was a definite loss in power dropping to the 48.
There are ways to control the mixture on a Weber if interested.
I am considering playing with fuel injection but I plan on using a Weber as the throttle body so the if anything goes wrong with the injection I can just flip a switch and change over to the carb.
Ken