FUEL TABLE FACTORS
Fuel table factors are used to scale fuel table cell values. They represent the actual value of a fuel
table cell with a value of 1. The maximum raw value of a cell is 255. Increase the factor to increase
fuel across the map.
- SD FACTOR - Fuel table cell factor for MAP load tables.
- MAF FACTOR - Fuel table cell factor for MAF load tables.
Injector sizes are used to calculate factors which are multiplied by the calculated values of
IPW to scale IPW across the board, such as when the actual injectors are changed, which is their
primary purpose. However, they can be modified from the actual injector flow capacity to fine
tune IPW. The factors are the ratio of BASE / CURRENT and BASE / ALTERNATE.
- BASE - This is the actual stock injector size installed when base tunes are developed.
- CURRENT - This should be the currently installed injector size.
- ALTERNATE - This can be used when switching between alternate fuels. This factor is
used when USE ALT INJECTOR SIZE is set when switching to either
ALTERNATE MAPS or
INJECTOR BATTERY OFFSET
Injector battery offset, also know as "injector latency" or "injector dead time", is the time required
for an injector to open from when energized. Since an injector is basically a solenoid, the latency
varies with battery voltage.
- INJECTOR BATTERY OFFSET - Sets the time in msec required to open an injector based on
INJECTOR CLOSE TIMING
Injector close timing specifies when the injectors are closed relative to TDC exhaust stroke.
- INJECTOR CLOSE TIMING - Sets the injector closed timing based on RPM. Negative values are
ATDC exhaust stroke. Positive values are BTDC exhaust stroke.
Cranking mode begins when the starter is engaged and ends when either the starter is released
or MAX RPM is reached.
While in cranking mode, cranking IPW is set from the Cranking Injector Pulsewidth table
and then reduced by the factor from the Cranking RPM Factor table.
The active injector size factor is then applied.
When the starter is released, or the MAX TIMER expires, cranking IPW
is decayed at the DECAY FACTOR rate. Timer expiration does not
cancel cranking mode.
The normal IPW is constantly calculated and compared to cranking IPW.
If cranking IPW is greater than normal IPW, Injector PW is set to cranking IPW.
This smooths the transition from cranking mode to normal operation.
Note that TTIF FACTOR increases normal IPW for some engines
while cranking mode is active.
While cranking mode is active, the injectors are fired in batch mode. The IPW in
batch mode is half of the logged Injector PW value. In batch mode, all injectors are fired once
every crank revolution (every other cycle). When cranking mode is exited, and cylinder
1 sync has occurred, batch mode is exited and sequential injection begins.
- MAX RPM - Once the engine reaches this RPM, cranking mode is exited.
- DECAY FACTOR - Sets the rate at which the cranking IPW is decayed.
- MAX TIMER - Sets the maximum amount of time for cranking mode. When this timer
expires, cranking IPW is decayed at the DECAY FACTOR rate.
- TTIF FACTOR - Total TIF is multiplied by this factor to increase the normal IPW
calculation during cranking mode.
Cranking Injector Pulsewidth
- Cranking Injector Pulsewidth - Sets the cranking IPW based on ECT.
Cranking RPM Factor
- Cranking RPM Factor - Reduces cranking IPW based on RPM.
POST START PARAMETERS
While in cranking mode, post start enrichment, or Post Start Trim, is initialized from the
INITIAL ENRICHMENT table. When cranking mode is exited, Post Start Trim
decays at a rate based on either WARM DECAY or
COLD DECAY, depending on ECT at startup above or below WARM DECAY ECT.
The decay is subtracted from Post Start Trim every 100msec.
- WARM DECAY - Sets the Post Start Trim decay rate when startup ECT is above
WARM DECAY ECT.
- COLD DECAY - Sets the Post Start Trim decay rate when startup ECT is below
WARM DECAY ECT.
- WARM DECAY ECT - Selects the Post Start Trim decay rate.
- INITIAL ENRICHMENT - Sets the initial Post Start Trim based on ECT.
ECT enrichment, or ECT Trim provides extra enrichment during warmup based on ECT.
ECT Trim can be reduced by the factor from the RPM FACTOR table based on RPM.
- ECT ENRICHMENT - Sets ECT Trim based on ECT.
- RPM FACTOR - Provides a means to reduce ECT Trim based on RPM.
IAT FUEL TRIM
IAT fuel trim, or IAT Trim, provides a means to either add or subtract fuel based on
density corrected IAT.
NOTE: IAT Trim is applied ONLY when the active load source is MAP.
- IAT FUEL TRIM - Sets IAT Trim based on density corrected IAT. Positive
values increase fuel.
IAT DENSITY CORRECTION
IAT density correction provides a means to apply a portion of ECT to the IAT measurement
to more precisely calculate the actual temperature of the air entering the combustion chamber.
The calculation is:
density corrected IAT = (IAT x factor) + (ECT x (1 - factor))
- Enable Density Correction - Enables density correction. If disabled, IAT alone
is used in place of density corrected IAT.
- Density Correction Table - This table, based on MAP load and RPM, contains factors that
are the percentage of IAT to be used to calculate density corrected IAT. The MAP and RPM
scales can be edited.
BOOST FUEL COMPENSATION
Boost fuel compensation, or Boost Trim provides additional fuel based on MAP and can be
used to simplfy tuning when increasing boost pressure.
NOTE: Boost Trim is applied ONLY when the active load source is MAP.
- BOOST FUEL COMPENSATION - These are factors that are applied to IPW to increase IPW
based on MAP, or boost pressure.
BARO FUEL COMPENSATION
Baro fuel compensation, or BARO Trim provides a means to add or subtract fuel
based on barometric pressure to compensate for altitude and atmosphereic changes when
running ITBs using TPS as the load source.
NOTE: BARO Trim is applied ONLY when the active load source is TPS.
- BARO FUEL COMPENSATION - These are factors that are applied to IPW to increase or
decrease IPW based on BARO sensor voltage.
See also BARO SENSOR SETUP.
Knock enrichment, or Knock Trim, provides a means to enrichen the fuel mixture when the
timing is being retarded due to knock analysis.
- ENRICHMENT DECAY FACTOR - Subtracted from Knock Trim every 100msec.
- KNOCK ENRICHMENT TABLE - This table contains fuel enrichment factors based on the
number of degrees the knock analysis system is retarding the timing.
[-] CYLINDER TRIMS