How does this target AFR table look?, VE table results after autotune |
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How does this target AFR table look?, VE table results after autotune |
rwilner |
Mar 28 2012, 08:36 AM
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#1
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No Ghosts in the Machine Group: Members Posts: 953 Joined: 30-March 10 From: Boston, MA Member No.: 11,530 Region Association: North East States |
I'm going to use the autotune feature of Microsquirt to set my fuel map (VE table). This system will automatically adjust the VE to achieve the mixture as defined by the target AFR table.
This is a 12x12 table. The Y axis is MAP reading (load), and the X axis is RPM. This table was auto-generated by this microsquirt calculator. What do you guys think? Is this a solid target AFR table or are adjustments needed? |
McMark |
Mar 30 2012, 11:27 AM
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#2
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
The retard connection is manifold vacuum and the advance port is at the throttle plate. At zero throttle the retard side of the vac canister has full engine vac and the advance side has no vac, so you get full retard. As the throttle opens you get decreasing manifold vac and increasing advance vac. At some point the venturi effect produces more vacuum on the advance side of the vac can. Did I get that right?
It's an interesting and complicated setup. Another side benefit I see is that on overrun/deceleration the timing is retarded which is could be a good idea when leaning out on overrun. |
rwilner |
Mar 30 2012, 12:00 PM
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#3
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No Ghosts in the Machine Group: Members Posts: 953 Joined: 30-March 10 From: Boston, MA Member No.: 11,530 Region Association: North East States |
The retard connection is manifold vacuum and the advance port is at the throttle plate. At zero throttle the retard side of the vac canister has full engine vac and the advance side has no vac, so you get full retard. As the throttle opens you get decreasing manifold vac and increasing advance vac. At some point the venturi effect produces more vacuum on the advance side of the vac can. Did I get that right? It's an interesting and complicated setup. Another side benefit I see is that on overrun/deceleration the timing is retarded which is could be a good idea when leaning out on overrun. In control systems land we call this "hysteresis," which means that the system output is a function not only of the instantaneous input but also some finite number of past inputs. The basic concept is illustrated via the graphs below. The second one shows the hysteresis, which is how I believe the factory setup works. |
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