SMT8-FT TECHNICAL MANUAL

Perfect Power Online Manuals.

 

Support for your SMT8-FT Unit.

AFR (LAMBDA) MODIFICATIONS

The purpose of the AFR (Lambda) modification channel is to change the AFR reading the ECU receives from an exhaust sensor. This in turn affects the ECU fuel loop. Thus AFR tuning becomes a powerful tool for fuel modifications.

 

Note : The narrow band circuit has been designed to work with Bosch 4 wire narrow band lambda probe; the circuit is loaded with a 10K resistor which could cause other sensors to operate outside of their normal voltage range.

 

ASSOCIATED PINS

 

AFR (IN)
Pin 4 of 12

AFR (OUT)
Pin 10 of 12

 

SMT8-FT - Narrow Band Lambda Wiring

NARROW BAND LAMBDA WIRING

 

NARROW BAND

 

The narrow band sensor has an output signal from 0 (lean) to 1Volt (rich). This signal can be interpreted by the SMT8-FT and it is available for display in AFR or Lambda. The signal from the sensor is routed to the AFR (IN) pin and exits the unit by the AFR (OUT) pin. The table entry is in AFR or LAMBDA, depending on the "UNITS" choice (Tools).

 

SMT8-FT - ShiftF2 - System Definition

SMT8-FT - F4 - Lambda/AFR Modification

In the above example the input AFR is at 13.9, the modification value that has been entered is -1.0, the result is that the output AFR is now 12.9 this in result causes the  closed loop system to begin leaning the mixture out.

 

 

SYSTEM DEFINITION SETUP

 

The unit has  a SYSTEM DEFINITION field for ticking items on/off. Following is an explanation of each field.

 

SMT8-FT - ShiftF2 - System Definition

NEG. CRANK EDGE
This selects the NEGATIVE CRANK edge. Only important when ignition is used.

 

HIGH CRANK LVL
This selects a higher crank trigger level. Recommended if the crank signal is noisy.

 

RPM FROM INJECT
This instructs the unit to compute the RPM from the injector signal. The RPM will go zero while you are coasting downhill.

 

ANA IS AFR INPUT
The analog input is used for AFR/Lambda measuring. The analogue map is disabled.

 

PROTECT ANA EN
This allows the protection circuit to influence the analog modification.

 

PROTECT ANA INV
This influences the analogue modification in the opposite direction.

 

PROTECT INJ CUT
This enables the cutting of the injector signal once the protection comes on.

 

PROTECT IGN CUT
This enables the cutting of the ignition signal when the protection comes on

 

PROTECT IGN RET
This enables the retardation of the ignition signal when the protection comes on