fuelsettingshelp
Differences
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fuelsettingshelp [2009/03/09 06:52] twdorris |
fuelsettingshelp [2010/02/26 13:13] twdorris |
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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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