7.7 Table Choices 7 ADDITIONAL ITEMS: BEYOND BASIC FUEL AND IGNITION CONTROL
7.7 Table Choices
For many installs a single fuel table is all that is required. New users are strongly advised to start with a
single table.
MS3Pro offers a number of methods of switching and blending between tables. These methods can be used to
effectively extend the basic table size, for better tunability with different fuel algorithms (e.g. low vs high rpms), for
dual fuels, or for different fuel mixes. Presently, fuel, ignition, boost and AFR targets may be blended or switched.
Due to the complexity introduced with multiple tables, only experienced users should consider enabling these
features. Additionally, the algorithm blending should only be enabled once each table is well tuned. Autotuning
(VE Analyze Live) will not function on some combinations of blended tables.
Terms used:
• Table switching - the ability to swap from one table to another, based on RPM, TPS, MAP or a physical switch
input
• Combined tables - two tables are combined to give a single VE (or spark) result
• Algorithm blending - two tables with different calculation algorithms are used to calculate fuel (or spark) and
then the result is blended together
• Dual table - two tables operate independently to control injectors or injector banks
• Staged injection - one fuel calculation control two banks of injectors. e.g. small injectors for idling and larger
injector for full power. (See Staged Injection page.)
Algorithms are different strategies for determining the "load" on an engine and then calculating fuel and spark etc.
As a brief recap:
• Speed-Density - Uses MAP as load.
• Alpha-N - Uses TPS as load.
• MAF - Measures actual airflow. Spark load uses a calculated percentage of cylinder filling.
• %baro - Uses MAP divided by barometric pressure as load.
• ITB - Uses a mix of MAP and TPS as load.
7.7.0.1 Example scenarios Why use table switching or blending at all? Actually, most users won’t need to,
and can get by just fine with a single table. Here are some examples of engines that could genuinely need table
switching or blending.
• A big block Chevy has two different types of port designs, one half of which flow considerably better than the
other half. Such an engine may need true dual table mode (although you can also use the individual cylinder
trim to achieve the same effect.)
• A large cammed motor with a poor MAP signal below 2,000 RPM that stabilizes at higher RPM could use
blended alpha N and SD, with the motor running on alpha-N at low RPM and speed density at high RPM.
• A turbo motor with a very large MAF for good fuel metering that runs out of MAF resolution at low flow could
use blended speed density and MAF fueling, with speed density at low RPM and the MAF at high RPM.
• A motor with a very wide powerband could use two separate speed density tables, switching them based on
RPM. This can effectively be used to create a 30 x 16 fuel table.
• A motor with switchable intake runners could use separate tables for when the long runners are open vs
when the short runners are open.
• A race car that runs in classes with different fuel requirements could have separate maps for pump gas and
race gas.
• A vehicle with a flex fuel sensor can blend in between separate gasoline and ethanol maps, interpolating
between the two for the percent of fuel in the tank.
AMP EFI MS3Pro manual version 1.202, firmware 1.5.0, 4/21/2017 Page 216
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