Smt8x Technical Manual Letripp II
Smt8x Technical Manual Letripp II
Smt8x Technical Manual Letripp II
Technical Manual
LetRipp II
Table of Contents: Page no:
1. INTRODUCTION ...................................................................................................1
2. FEATURES ............................................................................................................1
2.1 ANALOG MAP ................................................................................................. 1
2.2 IGN MAP ....................................................................................................... 1
2.3 WIDE BAND AFR MODIFICATION ...................................................................... 1
2.4 NARROW BAND AFR MODIFICATION ................................................................. 1
2.5 CALIBRATION ................................................................................................ 1
2.6 MAP SWITCHING............................................................................................ 1
2.7 DISPLAY ....................................................................................................... 2
2.8 HELP ............................................................................................................ 2
3. GENERAL USE OF THE WINDOWS SOFTWARE ......................................................2
3.1.1 USB COMMUNICATION ............................................................................. 2
4. CONNECTIONS .....................................................................................................3
4.1 PIN-OUT TABLE.............................................................................................. 3
4.2 SPECIFICATIONS ........................................................................................... 4
5. RPM TRIGGER INPUT ...........................................................................................4
6. ANALOG MODIFICATION ......................................................................................5
6.1 USAGE.......................................................................................................... 6
6.2 ASSOCIATED PINS ......................................................................................... 6
6.3 REQUIREMENTS ............................................................................................. 6
6.4 MAIN (RPM/THROTTLE) MAP ............................................................................ 6
6.5 COMPLETE CALCULATION ................................................................................ 6
6.6 PARAMETERS................................................................................................. 6
7. IGN (IGNITION) MAP...........................................................................................7
7.1 PURPOSE ...................................................................................................... 7
7.2 ASSOCIATED PINS (ON 14 PIN CONNECTOR) ..................................................... 7
7.3 PARAMETERS................................................................................................. 7
7.4 MAPPING ...................................................................................................... 8
7.4.1 MAIN (RPM / THROTTLE) MAP.................................................................... 8
7.4.2 IGNITION SETUP ..................................................................................... 9
8. MAP SWITCHING..................................................................................................9
8.1 MECHANICAL SWITCH .................................................................................... 9
9. NARROW AFR (LAMBDA) MODIFICATIONS ........................................................10
9.1 ASSOCIATED PINS ........................................................................................10
9.2 ANALOGUE AFR MODIFICATIONS.....................................................................10
10. WIDE BAND AFR MODIFICATIONS .....................................................................10
10.1 ASSOCIATED PINS ........................................................................................10
10.2 WIDE BAND CONNECTIONS ............................................................................11
10.3 WIDE BAND SENSOR .....................................................................................11
10.4 MAPS ..........................................................................................................11
10.5 AFR TUNING .................................................................................................12
10.6 TUNING BOTH SET OF SENSORS FROM ONE MAP...............................................12
11. KEYWORDS ........................................................................................................12
11.1 ECU.............................................................................................................12
11.2 MAPPING .....................................................................................................12
11.3 INTERCEPTING .............................................................................................12
11.4 TEE IN .........................................................................................................12
11.5 LAMBDA, OXYGEN, AFR..................................................................................12
11.6 CHIPPING ....................................................................................................12
11.7 MAF ............................................................................................................13
11.8 MAP ............................................................................................................13
11.9 AMP ............................................................................................................13
11.10 MAP SWITCHING .......................................................................................13
11.11 WIDE BAND LAMBDA ..................................................................................13
11.12 PICKUP.....................................................................................................13
11.13 FEED-THRU ...............................................................................................13
11.14 BALANCED INPUT ......................................................................................13
11.15 MAP SWITCH INPUT ...................................................................................13
LetRipp II SMT8X_Technical Manual V1.0 www.perfectpower.com i
11.16 DEFLECTION OR THROTTLE INPUT ...............................................................13
11.17 ETC..........................................................................................................13
12. PIN OUT BY FUNCTION ......................................................................................14
12.1 POWER ........................................................................................................14
12.2 THROTTLE INPUT ..........................................................................................14
12.3 CRANK INPUT ...............................................................................................14
12.4 CRANK OUTPUT ............................................................................................14
12.5 ANALOG.......................................................................................................14
12.6 MAP SWITCH ................................................................................................14
12.7 NARROW AFR ...............................................................................................14
12.8 WIDE AFR ....................................................................................................14
Welcome to the Digital Data Systems SMT8_X Technical Manual. The Technical Manual needs to
be used in conjunction with the LetRipp II Software User Guide.
The SMT8_X is the result of many years of development in the “Piggy-Back” industry. Its
performance is complemented by other SMT8, SMT8_L and SMT8_T products. This product was
optimized for 6-8 cylinder lambda (closed loop) modifications, and specifically fuel economy.
2. FEATURES
An analog signal is intercepted via the ANIN (pin 9/14) to AOUT (pin 12/14) connections. It is
mapped via Throttle/RPM for the purpose of altering fuel at specific engine conditions. The output
signal can be limited (high and low). This map is helpful to restrict manifold pressure or modify
airflow.
One ignition signal (CRANK) can be intercepted and mapped for the purpose of
retarding/advancing the ignition. The output signal can be set to maximum advance and retard
limits. This map is particular helpful to advance the ignition at cruising and low loads with high
octane fuel. For engines with multiple and variable CAM’s a different unit is available.
Two wide band LSU-4 channels can be tuned simultaneously. A large 16 x 24 map allows for the
precise AFR (Lambda) signal modification via the WAFR1 (pin 3/14) and WAFR2 (pin 4/14).
Two narrow band AFR probes can be tuned simultaneously. A large 16 x 24 map allows for the
precise AFR (Lambda) signal modification via the NAF1IN (pin 14/14) and NAF2IN (pin 7/14) to
the NAF1OUT (pin 13/14) and NAF2OUT (pin 6/14). The narrow band signal can also be tuned
from the wideband map by activating a LINK feature.
As an alternative, these two narrow band channels can be converted to two analogue channels in
the system definition. Then the map entries are in volts. This feature allows the AFR modification
of other probes than BOSCH.
2.5 CALIBRATION
The Throttle and RPM range can be calibrated and specified. The Calibration is applicable to both
tune maps A/B.
The unit has a ‘Map switching’ feature. It contains 2 sets of maps, which can be toggled from an
optional switch. In the absence of this switch the unit operates from map ‘A’.
LetRipp II SMT8X_Technical Manual V1.0 www.perfectpower.com 1
2.7 DISPLAY
The SMT8_X has an external display feature, which is set up by the PC. Up to 8 displays can be
driven, showing 8 selectable engine measurements. The display itself is an option.
2.8 HELP
This is explained in the LETRIPP II SOFTWARE USER GUIDE, and covers items like software
installation, the use, and features.
The SMT8_X uses a USB2.0 communication. The supplied cable should be used or any standard
cable with an ‘interference prevention ferrite’.
SMT 8_X
Main Connector
Display
2 14 13 12 11 10 9 8
1 7 6 5 4 3 2 1
The SMT8_X derives the RPM reading from the CRANK signal input (+IGIN, pin10/14).
The SMT8_X has one trigger input and output located on the 14 pin connector.
ECU
SMT8 X
CB1 + out
Pin 2 of 14
CB1 + in
Cut Pin 10 of 14
Engine
The type of trigger signal used is set up via the parameter screen.
The SMT8_X can modify one analog signal, namely ANIN and output the mapped signal on AOUT.
ECU
SMT8 X
Cut
Pin 9 of 14
Analog 1 in
Engine
AFM or MAP
Most analog signals, with a few exceptions, range from 0 to 5 Volts and are used by the ECU to
determine the fuel quantity. By routing the signal through the SMT8_X the analog voltage is
changed, which in turn results in a fuel change. Thus, allowing the car to be tuned. The input to
output voltage relationship can be changed at various engine-operating points. This process is
called “MAPPING”.
6.3 REQUIREMENTS
For the Throttle (deflection) to work: Connect pin 11 of the 14-pin connector to the analog
deflection signal (normally the throttle position sensor).
All map entries are in counts (without a decimal point) 100 counts entry equals 1.00 Volts.
6.6 PARAMETERS
7.1 PURPOSE
The ignition angle of an engine can be modified (retarded or advanced) to achieve one of the
following effects:
A) More power with high quality fuel (advance).
B) Avoid detonation after a turbo (Supercharger) installation (retard).
C) Retarding for poor quality fuel.
There are numerous other applications, which require better ignition angle control. Ignition
control is not successful on engines with active knock sensor control.
CRANK : 10 2
ECU
SMT8 X
CB1 + out
Pin 2 of 14
CB1 + in
Cut Pin 10 of 14
Engine
START SECONDS
This is the time in seconds after starting the SMT8X waits before it will modify the ignition signal.
IGNITION WINDOW
This allows the SMT8_X to be less sensitive to the incoming ignition/crank signal. A value of –1
will disable the SMT8_X’s error checking of the incoming signal. Typical values of 1 to 30 are
normal.
The Ignition signal can be mapped within the specified (above) limits by:
For the Throttle to work: Connect pin 11 of the 14-pin connector to the analog deflection signal
(normally the throttle position sensor).
Enter a number in the range from the max retard limit to max advance limit on the main map.
Zero, will do no modification to the signal!
CRANK ACTIVE
This indicates that the SMT8_X sees an input on the
Crank, pin 10/14
RETARD ONLY
This indicates that the SMT8_X cannot decode the
crank signal and will retard only.
Must be set correctly. If they are set correctly and the RETARD ONLY indication persists then this
means that the SMT8_X is unable to work with this crank signal.
If the engine runs with it, then you have to be content to have the ability to retard the timing.
8. MAP SWITCHING
The SMT8_X comes with two entirely separate tune maps in memory. We call them map “A” and
map “B”. The LETRIPP Software displays the present map in the upper right hand corner or in the
STATUS display. Two maps are used for:
• Performance versus Economy
• Tested versus un-tested
• Normal versus high altitude
• Good fuel versus bad fuel
• Weather
NOTE: Please make sure that you have a valid tune map in map “B” before you
flip the switch.
There is an option to connect (pin 5/14) an external mechanical switch to the SMT8X to enable
it to do map switching. Without this mechanical external switch, the unit will default on power up
to Map A (open pin). Should the mechanical switch be installed, the unit will power up and run on
the map selected. The transition between maps switching is seamless and can be performed
while the vehicle is in operation, provided both maps are loaded.
Map A
Pin 5 of 14
SMT8 X
Map B
Pin 5 of 14
The SMT8_X has 2 narrow band AFR channels; both are modified with the same map. The
purpose of the AFR (Lambda) modification channels is to change the AFR reading the ECU
receives from an BOSCH exhaust sensor. This in turn affects the ECU fuel loop. Thus AFR tuning
becomes a powerful tool for fuel modifications.
NAF1IN Pin 14 of 14
NAF1OUT Pin 13 of 14
NAF2IN Pin 7 of 14
NAF2OUT Pin 6 of 14
SMT8 X SMT8 X
Cut Cut Lambda #1 in
Lambda in Pin 14 of 14
Pin 14 of 14
Cut Lambda #2 in
Pin 7 of 14
The two channels can be converted to analogue channels by ticking the SYSTEM DEFINITION
boxes. This allows a voltage from 0-5Volts to be modified, instead of the traditional 0-1Volt
signal. In the analog mode the map entries are in volts. The connections stay the same. Of
course, a 0-1Volt BOSCH signal can also be modified in this mode.
This feature allows the ‘TUNING’ of two BOSCH LSU4 sensors. The tuning is independent of the
two narrow band channels. Both channels are mapped by the same modification.
WAFR1 Pin 3 of 14
WAFR2 Pin 4 of 14
WB Lambda #2 in Pin 4 of 14
SMT8 X SMT8 X
WB Lambda in WB Lambda #1 in
Pin 3 of 14
Pin 3 of 14
Therefore the voltages on the sensor are meaningless, but the current through the calibration
resistor is a measure of the AFR.
10.4 MAPS
The entered Map modification values are not precise. The reason for this is that current/AFR ratio
is un-linear. However, the error is relative small when compared to the AFR range.
You can tune the NARROW and the WIDE BAND probes separately by entering numbers in to the
respective maps.
Positive numbers in the narrow band map make the mixture APPEAR richer, thus the ECU will
reduce the fuel.
Positive numbers in the wide band map will make the mixture APPEAR leaner, thus the ECU will
add fuel to restore the closed loop target.
The Wide band sensors are before the CAT. The entries in this map can be used to tune the
narrow band probes.
Requirements:
Set the SYSTEM DEFINITION: Link enabled
Set the SYSTEM DEFINITION: Inverse link (as required)
Set the PARAMETER: Link Multiplier to a value greater then ZERO
Tuning operation:
Display the narrow AFR value without and tuning.
Affect the wide AFR by a small amount and observe the changes in the narrow display. Reverse
the direction if indicated, and change the multiplier up or down to bring the narrow band display
in to range again.
The narrow band display must stay reasonable at 14.7 AFR with light throttle.
11. KEYWORDS
11.1 ECU
11.2 MAPPING
11.3 INTERCEPTING
A wire is cut, and the two ends are “routed” through the SMT8_X for the purpose of changing the
signal.
11.4 TEE IN
A wire from the SMT8_X is joined to the standard wiring loom. The signal is only read, and no
modifications take place.
A lambda probe, oxygen probe, or AFR sensor all measure the oxygen content in the exhaust
pipe. At lambda 1.00 the AFR=14.7 and a narrow band sensor generates a voltage between 0.2
and 0.8 Volts.
11.6 CHIPPING
Traditionally this applies to changing the “chip” of the ECU to provide better performance. When
ECU’s started to control the engine it meant changing an EEPROM. The term now also applies to
adding a SMT8_X to the car, without changing any chips or EEPROMS. The SMT8_X has the
advantage over chipping because of the online tune and the retune capability.
Mass Air Flow sensor. It could be a device with a “FLAP” or a solid-state “hot wire” sensor. It
generates basically an analog output voltage, which increases with higher airflow. Some devices
compensate for air temperature (density).
11.8 MAP
Manifold Absolute Pressure. It is a solid-state device with 3 wires and provides an analog output
voltage, which increases as the manifold pressure increases. Since it measures the absolute
pressure the output voltage DECREASES at idle. We don’t like this term because is also applies to
a tuning map.
11.9 AMP
Absolute Manifold Pressure. The same thing as a MAP! We like this term because it can’t be
confused with a tuning “map”.
All of our units have two tuning maps, which can be switched while driving. There are THREE
possible map-switching scenarios.
This is a 5 wire lambda probe (BOSCH LSU-4) with the part number starting with 025800. The
SMT8_X can modify it. This probe is very popular because it measures the AFR very fast and at
very RICH mixtures, which is useful for turbo/supercharger applications.
11.12 PICKUP
It is a sensor, which “picks up” an engine measurement like temperature or crank angle position.
The sensor can be a Hall Effect (square wave) or magnetic (sine wave).
11.13 FEED-THRU
A method where a wire is cut and routed through the SMT8_X for the purpose of modifying the
electrical signal.
Refers to a magnetic pickup (CRANK) where the pickup coil is isolated from ground. If a balanced
input is tested with a scope, then both wires have an opposing signal on it.
It is a tee-in signal in the range from 0 –5Volts. Normally a low voltage refers to a closed
throttle.
11.17 ETC
Electronic throttle control. This is a throttle body that is controlled by the ecu electronically and
not by a conventional cable. The ETC has a ‘feedback’ signal, which can be used as a TPS input.
12.1 POWER
Ground 1-14
+13V 8-14
12.5 ANALOG
ANIN 9-14
AOUT 12-14