terrass604
Registered
I would like to start an open discussion on how the Suzuki FI and ignition timing works. The following is my understanding of the system:
1. The ECU has a different timing map for each gear.
2. The ECU has a neutral timing map and a map used when the clutch is pulled in.
3. The ECU retards the lower RPM timing in gears 1-4 unless the throttle is wide open.
4. The ECU retards the timing in 6th gear at 10,500 rpm or so to limit the speed.
Questions:
1. Is the above true?
2. Does the ECU have a separate FI (fuel) map for each gear, plus neutral?
I just bought a PCIIIr (with timing adjustment) and have looked at the TRE and ATRE units. The PCIIIr has a single FI (fuel) map as the PCIIIr does not use gear information and also a single timing map, both based on RPM and throttle position only.
The ATRE uses a single ECU gear map (selectable) for timing, most users selecting the 5th gear mapping as it does not have the 1-4th gear retarding and the 6th gear limiter.
I checked with Powercommander and they do not recommend using the timing feature of the PCIIIr as it would override the ECU timing and use a single curve for all conditions. This makes the –r version kind of useless it seems to me. The PCIIIr still has only a single FI map for all gears anyway, so I am getting confused about the system in general.
In the ‘old’ days, you had a single timing curve, with advance, for the engine and a single fuel metering ‘curve’ at the carbs. The engine did not care what gear you were in. If the stock ECU has a fuel metering curve and a timing curve for each gear, how would the PCIII provide accurate fuel metering if the ECU is changing the timing for each gear? Seems like it would be more accurate to use an ATRE (with a single timing curve) with the PCIII (with a single fuel curve) instead.
Would appreciate any discussion about the above.
<!--EDIT|terrass604
Reason for Edit: None given...|1078238086 -->
1. The ECU has a different timing map for each gear.
2. The ECU has a neutral timing map and a map used when the clutch is pulled in.
3. The ECU retards the lower RPM timing in gears 1-4 unless the throttle is wide open.
4. The ECU retards the timing in 6th gear at 10,500 rpm or so to limit the speed.
Questions:
1. Is the above true?
2. Does the ECU have a separate FI (fuel) map for each gear, plus neutral?
I just bought a PCIIIr (with timing adjustment) and have looked at the TRE and ATRE units. The PCIIIr has a single FI (fuel) map as the PCIIIr does not use gear information and also a single timing map, both based on RPM and throttle position only.
The ATRE uses a single ECU gear map (selectable) for timing, most users selecting the 5th gear mapping as it does not have the 1-4th gear retarding and the 6th gear limiter.
I checked with Powercommander and they do not recommend using the timing feature of the PCIIIr as it would override the ECU timing and use a single curve for all conditions. This makes the –r version kind of useless it seems to me. The PCIIIr still has only a single FI map for all gears anyway, so I am getting confused about the system in general.
In the ‘old’ days, you had a single timing curve, with advance, for the engine and a single fuel metering ‘curve’ at the carbs. The engine did not care what gear you were in. If the stock ECU has a fuel metering curve and a timing curve for each gear, how would the PCIII provide accurate fuel metering if the ECU is changing the timing for each gear? Seems like it would be more accurate to use an ATRE (with a single timing curve) with the PCIII (with a single fuel curve) instead.
Would appreciate any discussion about the above.
<!--EDIT|terrass604
Reason for Edit: None given...|1078238086 -->
