fuelsettingshelp
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fuelsettingshelp [2009/02/16 08:41] twdorris created |
fuelsettingshelp [2010/02/26 13:13] twdorris |
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| This page describes the basic usage of the Fuel tab in the ECU Config section of the ECMLink application. This page is just a dump and reformat of the same information provided in the help file with the ECMLink application. | This page describes the basic usage of the Fuel tab in the ECU Config section of the ECMLink application. This page is just a dump and reformat of the same information provided in the help file with the ECMLink application. | ||
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| ===== Fuel Adjustments Table ===== | ===== Fuel Adjustments Table ===== | ||
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| The adjustment described in the preceeding pargraph is fully applied only when the value for LoadFactor (essentially the same as Airflow/rev, or Boost) is above 1.6 (about 10 psi of boost). Below a LoadFactor of 0.8 (roughly atmospheric pressure) none of the adjustment is applied. Between a LoadFactor of 0.8 and 1.6, the adjustment is applied proportionally. For example, a -5% adjustment value at a LoadFactor of 1.0 results in a -1.25% adjustment actually applied: | The adjustment described in the preceeding pargraph is fully applied only when the value for LoadFactor (essentially the same as Airflow/rev, or Boost) is above 1.6 (about 10 psi of boost). Below a LoadFactor of 0.8 (roughly atmospheric pressure) none of the adjustment is applied. Between a LoadFactor of 0.8 and 1.6, the adjustment is applied proportionally. For example, a -5% adjustment value at a LoadFactor of 1.0 results in a -1.25% adjustment actually applied: | ||
| - | -5% * (1.0 - 0.8) / (1.6 - 0.8) = -1.25% | + | Real adj = -5% * (1.0 - 0.8) / (1.6 - 0.8) = -1.25% |
| Multiple contiguous fuel adjustment points may be selected by holding the Shift key and using the mouse or the left/right arrow keys, and adjusted simultaneously in equal increments using the up/down arrow keys. | Multiple contiguous fuel adjustment points may be selected by holding the Shift key and using the mouse or the left/right arrow keys, and adjusted simultaneously in equal increments using the up/down arrow keys. | ||
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| The **Global fuel** and **Deadtime** adjustments are intended to be used mainly to compensate for injectors and fuel pressure that differ from stock. They are applied at all times. | The **Global fuel** and **Deadtime** adjustments are intended to be used mainly to compensate for injectors and fuel pressure that differ from stock. They are applied at all times. | ||
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| ==== Global fuel ==== | ==== Global fuel ==== | ||
| - | The stock ECU assumes that the car is equipped with 450 cc/min injectors and a fuel pressure of either 37 psi (1G) or 43.5 psi (2G). As injector size is increased, the Global fuel adjustment must be made more negative. Reducing the **Global fuel** adjustment value to, say, -50% to compensate for 900 cc/min injectors cuts fuel delivery in half. | + | The stock ECU assumes that the car is equipped with 450 cc/min injectors and a fuel pressure of either 37 psi (1G) or 42.6 psi (2G). As injector size is increased, the Global fuel adjustment must be made more negative. Reducing the **Global fuel** adjustment value to, say, -50% to compensate for 900 cc/min injectors cuts fuel delivery in half. |
| The needed Global fuel adjustment value may be calculated as follows: | The needed Global fuel adjustment value may be calculated as follows: | ||
| - | FlowRateAdj1G = squareroot(37.0 / BaseFuelPressure) | + | FlowRateAdj1G = squareroot(BaseFuelPressure / 37) |
| - | FlowRateAdj2G = squareroot(43.5 / BaseFuelPressure) | + | FlowRateAdj2G = squareroot(BaseFuelPressure / 42.6) |
| - | Adj = 100 * ( (450 / InjectorCCPerMin) * FlowRateAdj - 1) | + | FlowRateAdjEVO1-3 = squareroot(BaseFuelPressure / 42.6) |
| + | NewInjFlow = InjectorCCPerMin * FlowRateAdj | ||
| + | Adj = (100 * ( 450 / NewInjFlow ) ) - 100 | ||
| - | Where BaseFuelPressure is specified in PSI and InjectorCCPerMin is the flowrate of the injectors at 43.5psi (the standard flowrate reference pressure). Some slight emperical tweaking of this theoretically-derived value may be needed to get actual air/fuel ratios to match what the ECU intends. Since the Global fuel adjustment value is a multiplier applied to the injector pulsewidth, altering it tends to change the actual air/fuel ratio proportionally under all conditions. | + | Where BaseFuelPressure is specified in PSI and InjectorCCPerMin is the flowrate of the injectors at 43.5psi (the standard flowrate reference pressure). Some slight empirical tweaking of this theoretically-derived value may be needed to get actual air/fuel ratios to match what the ECU intends. Since the Global fuel adjustment value is a multiplier applied to the injector pulsewidth, altering it tends to change the actual air/fuel ratio proportionally under all conditions. |
| ==== Deadtime ==== | ==== Deadtime ==== | ||
fuelsettingshelp.txt · Last modified: 2024/03/15 11:16 (external edit)
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