Hi,
I've got a Porsche 928 with L-Jetronic that I am considering switching to VEMS. The car is configured with low impedance injectors - measure around 3.6 ohms on a warm engine. Wired together in parallel pairs (although the stock ECU likely fires all 4 pairs / 8 injectors at once).
What is the best option to drive these injectors? Low Voltage flyback? Power flyback? It is disappointing to see that VEMS does not have good support for low impedance injectors, when it seems in all other ways superior to MS-II.
I am trying to minimize the amount of mechanical changes, hence the desire to retain the original fuel injectors.
thanks,
-Ben
Wire each injector in series with a 6R8 50W resistor, and connect individually to the injector channels, the VEMS will need the 30V fly-back option.
This works perfectly well on all the LowZ injectors we've ever used, and is common practice in many OEM applications where a balast pack is used.
I've used power flyback with success on Low-Z injectors up to 500cc, on bigger ones I've used resistors and 30V flyback. You will have no problem using power flyback on such a small injectors of 928 although what year did they come with low-Z injectors? All of the 928's I've installed VEMS on (3 so far) have had high impedance injectors...
Quote from: PeepPaadam on June 03, 2009, 01:28:13 AM
I've used power flyback with success on Low-Z injectors up to 500cc, on bigger ones I've used resistors and 30V flyback. You will have no problem using power flyback on such a small injectors of 928 although what year did they come with low-Z injectors? All of the 928's I've installed VEMS on (3 so far) have had high impedance injectors...
1984, US version. I believe the 85 and up (and 84 Euro) used high impedance injectors