Differences

This shows you the differences between two versions of the page.

--- bcsoverview [2010/08/02 07:41]
twdorris
+++ bcsoverview [2011/08/12 09:14]
twdorris
@@ Line 8: / Line 8: @@
   - Adjust this value by some amount based on how far away current boost is from desired boost
-This sounds pretty simple and it really is, but once you start picking about the phrases, you'll see it's a bit more involved than it might seem at first.
+This sounds pretty simple and it really is, but once you start picking apart the phrases, you'll see it's a bit more involved than it might seem at first.
 A sample screen shot is provided below for reference in the following sections.
 {{  http://www.ecmtuning.com/wiki/_media/samplebcs.png  }}
@@ Line 23: / Line 24: @@
 If error correction has been __disabled__, then this value is the final value the ECU is going to use and your turbo will build whatever boost it just happens to build for the given wastegate duty cycle.  You can use this mode of operation during setup and dialin to find where you setup naturally needs to be to build the boost you're looking for.
-If error correction has been __enabled__, then the ECU references the Boost Target table to determine (for the same RPM and gear) what boost it should be trying to achieve at that moment.  It then adjusts the base duty cycle according (up or down).  It tracks this adjustment with a "trim" value, similar to the short term fuel trim.  The final duty cycle used by the ECU is basically:
+If error correction has been __enabled__, then the ECU references the Boost Target table to determine (for the same RPM and gear) what boost it should be trying to achieve at that moment.  It then adjusts the base duty cycle accordingly (up or down).  It tracks this adjustment with a "trim" value, similar to the short term fuel trim.  The final duty cycle used by the ECU is basically:
   Final DC % = (base DC %) + WGSTrim
@@ Line 61: / Line 62: @@
 Still, some folks may want to simplify their tuning efforts and focus on a single row at all times.  That's fine too, just keep in mind the expected results.
@@ Line 69: / Line 71: @@
 === WGSGear - Direct Access Table ===
-When this box is checked, you'll want to change the WGSGear table in Direct Access on the WGSMisc tab to have values related to the raw LatestSpeed variable (instead of the raw WGSGearRatio used by default).
+When this box is checked, you'll want to change the WGSGear table in Direct Access on the WGSMisc tab.  The default values are based on an internal (raw) ECU value named WGSGearRatio.  If you want to base gear selection on speed instead, then you'll need to change this table to reflect values from the internal ECU variable named LatestSpeed.  The following screen shot shows the WGSGear tab in direct access.
 {{  http://www.ecmtuning.com/wiki/_media/wgsgear.png  }}
-Display LatestSpeed on your graph using the Raw value -> button in the Display Values dialog.
+The values shown above are the default gear ratio values provided in ECMLink.  These values would select Gear 1 when WGSGearRatio is below 158.  Then it would select Gear 2 when WGSGearRtio is between 158 and 248.  Then it would select Gear 3 anytime WGSGearRatio is above 248.
+The ECU provides some internal hysteresis to limit sudden switching between gears.
+To change these values to reflect speed instead, calculate your speed points as:
+  WGSGear value = (speed in mph) / 1.2425
+So, for example, if you want to select 2nd gear at 40mph, you will use 32 as the Gear 1 value.  If you want to select 3rd gear at 80, then you'll use 64 as the Gear 2 value.
+You can also display the raw ECU value called LatestSpeed on your graph using the Raw value -> button in the Display Values dialog.  That's the value the ECU will compare against when doing gear selection based on speed.  You can use those values directly in the WGSGear table.

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