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I've run various jets sizes and air correction jets and measure AFR, but they can't change the fundamental behavior. Just decreasing the Air correction jet from #185 to #175 had minimal effect on the high end. Maybe a slight shift to a slightly richer top end, but 2000-4000 was the same: 185 or 175.
Per my simple flow analysis, I found the original 2.2l with the Zeniths and 27.5mm vents had a particular pressure verses fuel flow verses rpm relationship. A 3.0l w/Zeniths would be perfect with 31.5mm vents. All you would need is #55 idles, and ~145 or 150 mains. AFR would be pretty good across the range, because the pressure/flow/rpm would be about the same. Just scaled by the displacement, compression ratio and intake port size.
When we added the larger vents (34mm) we decreased the high rpm pressure signal hence less fuel = lean. We all ended up with either #160 or #165 mains to get a proper AFR at the high end. Low end is too rich.
We really need to change the emulsion tubes to get more air in the low end, so that the system can be re-balanced with the different pressure/flow/rpm signal coming from the larger vents.
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Mike
'82 911SC, SSI, 22/29 tbars, 22F/22R Adj swaybars, Bilstein Sport, Elephant polybronze & monoballs, Cambermeister bar, turbo tierods, Carrera oil cooler, front brake cooling ducts, Sparco Sprint 5 & Recaro SRD PAX seat, Teamtech harness, DAS Sport rollbar.
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