LoganD wrote: ↑
Tue Sep 10, 2019 9:46 am
I've seen carb intakes, both dual plane and single plane, with such bad distribution that one cylinder will be 16:1 and another will be 11:1. I'd weld bungs in each header tube and move the wideband around, you can use the jetting to help mitigate it but you'll never get it great.
Get rid of the 4-hole spacer.
I think this is the cullprit.
I have no solution to offer but my experience.
I have 8 WB's on my engine and I can see the difference. Obviously with EFI you can have the ecu correct for this. Corrections made by the ECU vary up to 30% from rich to lean cyls on the extreme side of things at idle and anything which is low speed driving.
What had me stumped is that even when balancing airflows between cyls, it still had the uneven AFR's (mine is an ITB manifold which makes individually balancing cyls possible)
What those imbalances in AFR do is that the lean ones start to misfire making for bad driveability, rough running,...
I thought that it could have something to do with injector angle but after I see this post it seems that a carb does the same thing...
On other issue could indeed be the cam. Although if intake reversion would be the reason I would suppose it would show up in the airflow differences...