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Surging Solutions in 2021?
- Thread starter johnwraystewart
- Start date
burnbender
Member
Surging ?
I always thought of the surge as personality.
I always thought of the surge as personality.
johnwraystewart
New member
So I installed the Autolites the other day, and it's 90% improved! It's not perfect, but it's damn good now.
thanks all!
thanks all!
nrpetersen
Curmudgeon
The airheads use only a single throttle position sensor and a single catalytic converter/oxygen sensor to optimize combustion in two cylinders. Great, but the system depended on the second cylinder's metering process being similar enough to maintain combustion under near-closed throttle operation. Consider that for combustion to be stable, the air/fuel ratio has to be between about 8:1 and 18:1. Otherwise rough processor controlled operation could be expected as that "slave" cylinder drops in and out of combustion.
The fuel injectors probably can be relied upon to deliver the same amount of fuel to each cylinder. But a LOT of airflow happens in the first couple of degrees of throttle butterfly openings, and how much air also depends on intake valve timing.
I contend that oilhead surging may be caused by discrepancies in the amount of air supplied under near closed-throttle operation, causing a cylinder to drop out. There are two independent sources of air for each cylinder - the air horn butterfly and the big brass screws (BBS). The fuel injectors probably can be relied upon to deliver the same amount of fuel to each cylinder. This leaves air-flow variations beyond those limits of combustion to cause the non-optimized cylinder to drop out, resulting in surging.
If this is so, careful adjustment of the right side idle stop screw vs the right side BBS should be able to correct a much of this potential discrepancy although intake valve timing would still be super critical.
The fuel injectors probably can be relied upon to deliver the same amount of fuel to each cylinder. But a LOT of airflow happens in the first couple of degrees of throttle butterfly openings, and how much air also depends on intake valve timing.
I contend that oilhead surging may be caused by discrepancies in the amount of air supplied under near closed-throttle operation, causing a cylinder to drop out. There are two independent sources of air for each cylinder - the air horn butterfly and the big brass screws (BBS). The fuel injectors probably can be relied upon to deliver the same amount of fuel to each cylinder. This leaves air-flow variations beyond those limits of combustion to cause the non-optimized cylinder to drop out, resulting in surging.
If this is so, careful adjustment of the right side idle stop screw vs the right side BBS should be able to correct a much of this potential discrepancy although intake valve timing would still be super critical.
