Ifr being high has nothing to do with mains Or hsab.
The negative of a high ifr is getting air behind it.
On a stock engine? Maybe no biggie.
With a performance cam, the oscillatory flow can compress the air....
Submerged fuel restrictions are free from instability. Not so with ones that are exposed to air.
Drew, read my previous posts slowly.....LOL
I said the high or low IFR isn't the reason, but the low IFR/early blocks seemed to be missing main well kill bleeds in many cases when compared to modern carbs, and IMHO that makes the later carbs not work as well.
The IFR isn't doing it, it's just a design trend that I have seen happen about the same time
I prefer the low IFR for transition feed over a high one
unrelated to the discussion of the mains slow to come on line, because I also think that with heat they behave differently when submerged versus up top
My point on the HSAB is that if the main supply is slow you can't just shrink a HSAB to make them come in faster and still have the fuel curve right, and I also don't like throwing a ton of IFR fuel at the transition circuit to make up for lazy main circuit, never mind drenching it in pump fuel, although nobody has said to do that
Back to the original thing I said, often an early 1850, 3310, you name it, low IFR metering block can become magical on a later SA or HP series by just matching the new carb's PVCR, IFR and jets, maybe this more modern 3310 is the same, but my newest one is a -4. I blame it on main well design, I don't know why they changed designs so much (along with the IFR) but they did, often with very few other changes.
