Forum » General Tuning Discussion » Lag times, low ohm injectors running through resistor.

Lag times, low ohm injectors running through resistor.

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 


Page 1
Author
800 Views

When using say 2 ohm injectors on an ecu that can't use them and has to run through a resistor, [eg GTR, EVO] would the latency times supplied by the injector manufacturer be wrong as going though the resistor would slow down the time to open the injector? I am thinking it would make a big difference, what do the experts on here think.

The idea with a low impedance injector it to use a peak of current (>5A) to open them fast and then keep them open with a lot less current (~1A, close to a high impedance injector).

With a resistor you don't have that peak. So yes, it will change.

Currently i am facing the same situation.

Using a 2.2 Ohm low impedance injectors through resistor packs.

Dead times are far off.

Nightmare for a tuner.

Time for an injector test bench :D

Thanks guys.

This is an extreme example of what I mentioned in another thread - The dead time values can even be influenced by the injector drive of the particular ECU you're using. Driving a peak & hold injector with a saturated drive through a resistor pack would almost certainly have a significant effect on the injector operation and dead time.

While not specifically helpful to you, this situation is becoming less of a problem with the current EV14-based injectors available on the aftermarket all being high impedance, saturated drive design.

I had to use peak and hold injector driver which worked well

In this situation, I use an oscilloscope, and take a capture of the injector current. You'll see a dip in the ramp when the armature moves through the coil (injector opens). Measuring the time between injector on, and where the armature moves, will give you your dead time at the present supply voltage. On the injector voltage trace, you can also when it closes after it's turned off. Of course this doesn't account for when the flow actually happens, but it's close, and better than knowing nothing.