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Link G4 Plus Software Tutorial: Transient Tuning (Fuel and Ignition)

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Transient Tuning (Fuel and Ignition)

05.09

00:00 - While the main fuel and ignition tables can cope with tuning the engine during steady state running, some additional control is needed to handle transient situations where the throttle is opened quickly.
00:11 Adjustments are available to handle transient tuning for both fuel and ignition.
00:15 We will start by covering fuel which is normally referred to as acceleration enrichment.
00:21 We can access the acceleration enrichment by opening the ECU set up menu, clicking on fuel and then on acceleration enrichment.
00:28 This will show the available menus.
00:31 We will start by clicking on acceleration enrichment to view the main setup menu.
00:36 The first option is accel mode which tells the ECU which load input will be used to tell the ECU to apply acceleration enrichment.
00:44 The usual selection is TPS however we can also disable accel enrichment all together or use the MAP sensor if a TPS is not fitted.
00:53 The G4+ allows the amount of accel enrichment to be adjusted relative to the load placed on the engine.
01:02 The next option tells the ECU what input to use for the load axis.
01:06 Here we can select MAP, TPS or MAF.
01:10 The next option is accel sensitivity which controls how much fuel will be provided.
01:16 Increasing this number will increase the amount of acceleration enrichment.
01:21 Accel deadband can be used to stop noise or very small movements on the TPS signal from triggering acceleration enrichment.
01:29 The next setting we have is accel hold which controls how many injection events the full acceleration enrichment will be held for before decaying to zero.
01:39 The last setting is accel decay which controls how fast the accel enrichment is removed.
01:46 This number represents a percentage of the original acceleration enrichment that is removed each engine cycle.
01:52 Larger numbers here will remove the enrichment faster.
01:56 Once the basic settings have been adjusted, we can access the tables and optimise the accel enrichment.
02:02 The G4+ gives a lot of control here and there are three separate tables that you'll need to adjust.
02:09 The first is the accel load correction table.
02:12 This table controls the percentage of accel enrichment that will be applied at different load points.
02:19 Usually we'll find that an engine needs the most accel enrichment from closed throttle and progressively less enrichment as the load increases.
02:27 We can achieve this by adjusting the load correction table.
02:30 Note that 1.0 will give us full enrichment while zero will give no enrichment.
02:36 The next table to adjust is the accel clamp table.
02:41 This table controls the maximum amount of enrichment that will be applied in conjunction with the accel sensitivity setting.
02:48 The table is relative to RPM as generally an engine will need less accel enrichment at higher RPM.
02:55 Lastly we have the accel cold correction table which allows for additional accel enrichment when the engine is cold.
03:02 Like the load correction table, the numbers represent percentage of the normal accel enrichment.
03:09 I.e. 1.0 means no change while 3.0 will give three times the normal enrichment.
03:15 This table has engine temperature on the X axis.
03:19 Now let's look at the ignition.
03:21 The G4+ also gives the option of applying transient retard to the ignition timing.
03:26 While this function is seldom needed, occasionally it can be useful to help eliminate momentary knocking on sharp throttle application.
03:34 We can access the transient ignition retard function from the ignition menu and then click on transient ignition retard.
03:41 By default, this option is turned off so you first need to double click on mode and select on.
03:47 When you do this a window will ask if you wish to clear the table and set the default axis. click yes.
03:54 Before adjusting the actual table, we have two more settings to adjust.
03:59 Decay rate controls how quickly the ignition timing is added back in after the accel event.
04:04 This is in degrees per engine cycle.
04:07 Hold time controls how long the ignition timing will be retarded for.
04:12 This number represents engine cycles.
04:16 We can now open the ECU settings menu again and we can now access the transient retard table.
04:22 This is a 3D table with TPS delta on the Y axis and engine RPM on the X axis.
04:29 TPS delta means how fast the TPS changes.
04:33 Faster throttle openings will produce larger TPS delta values while under steady state running, TPS delta will be zero.
04:42 You can now adjust the amount of retard that will be applied relative to engine RPM and how aggressively the throttle is opened.