Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI System Hardware & BigComm Software - Manual (Page 88)

BigStuff3 Pro SEFI System
Version 2.1 – February 2011 81
48. TRANSIENT FUEL
Transient Fuel is the fuel added to the engine during non-steady state conditions as a function of
dTPSdt and dMAPdt. Transient Fuel is applied relative to a rate of throttle change (dTPS) and a rate
of MAP change (dMAP). TPS transient fuel is added asynchronously. Asynchronously means fuel
added between the regularly scheduled injector pulses. MAP transient fuel is added synchronously to
increase or decrease the base fuel pulse width.
MAP Transient Fuel: MAP (+) Transient Fuel can be compared to a carburetor’s power valve. It is
used to increase the base fuel pulse width when the manifold pressure increases significantly for a
slight change in throttle opening. MAP (-) Transient Fuel is used to decrease the base fuel pulse width
when the manifold pressure decreases significantly as a result of the throttle blades being closed.
The MAP (+) and (-) Transient Fuel control is comprised of 5 primary tables and 1 secondary table.
Each of the tables play an integral role as to how the base fuel pulse width will be increased or
decreased for a given change in manifold pressure. Below, is a description of how and when each of
the tables is used by the ECU.
From the tool bar on Main Menu screen, left click on “Transient Fuel”. The screen below will open.
The following paragraphs will describe how to calibrate each of the Transient Fuel drop down
selections.