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SMT7 | Frequently Asked Questions


Frequently Asked Questions.


What do the values of the SMT7's ignition map actually mean on the engine's timing?

The SMT7 doesn't know what the engine's timing is but it can advance or retard it. Positive values in the ignition map will advance the timing and negative values will retard the timing. Any value used will be added or subtracted from the base ignition timing. Zero entry will be the stock or base timing.

I am just wondering is it possible to use the SMT7 software and the LetRipp software with Windows 7 as I have a laptop with XP Pro but I need to update my computer with a newer faster one and they only have Windows 7?

Yes, the SMT7 and LetRipp can work on Windows 7 provided they are used by administrator privilege level.

Can the SMT7 do boost control and drive an extra injector?

Yes, a N75 valve for boost and a 13 ohm or higher injectors are no problem for the SMT7 piggy-back unit.

Is the SMT7 still manufactured and are new units available?

The SMT8, SMT8-L and SMT8-T piggy-back units have replaced the SMT7. We are no longer manufacturing the SMT7 piggy-back product.

Which of the SMT8's is the closest SMT7 equivalent?

The SMT8 has all of the SMT7's features including more.

What is PWM?

Pulse Width Modulation. The frequency doesn't change but the on to off time does.

What is a N75 valve?

It is a solenoid primarily used for boost control.

Is the SMT7 repairable?

We can repair SMT7's, but they are out of warranty and are no longer manufactured.

I have LetRipp software but I cannot communicate with my SMT7?

The SMT7 has its own software version and the LetRipp software will not work with the SMT7. The SMT7 product is an older model and is no longer manufactured. The SMT8 piggy-back with LetRipp software replaces the SMT7.

What is the "make permanent" button on the SMT7 for?

The SMT7 is tuned in real time but the map is not saved into the SMT7 unless you click the make permanent button. This is so you can change your map, but if you preferred the way it was before you started tuning you just had to turn the SMT7 off then on again and the map will return to original.

Which map is used to tune the extra injector?

F5 Inj map

I have teed onto the crank sensor with pin 2 of 18, the +crank input, but I don't see any rpm in the software when the engine is idling.

Turn the high crank level trigger on or off in the F2 ignition map. Also select the correct trigger type.

My crank signal is on one wire. How do I know if it is a magnetic or digital signal?

Easiest way is to check the signal with an oscilloscope, but not many people or workshops have this tool. Check the actual sensor, if there are two insulated wires and one screen wire (exposed wires) then the signal is magnetic. If there are three insulated wires and one wire will be 5 volts, one will be ground, and then the remaining wire is the digital signal.

Perfect Power use the term balanced crank signals. What does this mean?

This term means that there are two magnetic signals which are exactly opposite each other at all times.

What does analog mean?

A circuit or sensor that ranges from 0-5 volts.

I have wired my airflow meter into the analog 1 circuit but now my engine doesn't start?

Firstly, check the wiring. The wire from the meter must go to pin8/18 and the return wire to the ECU must be pin 1/16. Secondly, check the parameters for analog 1, the upper limit should be 5.00, the lower limit should be 0.00 and the zero offset should be 0.00. Thirdly, check the analog 1 map and side tables, the main map and the engine and air temperature maps should be zero, the AMP side map should be 1.00.

When I use the SMT7 to control the boost on my turbo car, the engine light keeps coming on and the error code is about the N75 valve. How do I fix this?

The ECU was controlling the N75 valve but now you have cut the wire to the N75 valve so the SMT7 can control it directly. What you need to do is wire a 1 KOhm quarter watt resistor onto the ECU wire and onto switched 12 volts.

There doesn't seem to be any links for the old SMT7 tuning software...please help?

The software can be downloaded in the software downloads section on the Perfect Power website.