Thunder Injector Wiring Dual Fuel Systems.

[exileperformance]

I looking to do a dual fuel system on a v8 engine with sequential injection. My thought is I would set the injector grounds up through a relay, I would have a switch that would trigger the relay for the set of injectors ground the switch would also toggle between the fuel tables. The plan would be to have methanol and gas, I could street drive on gas go to the track and warm the car up drive to the line, do the burn out and switch the fuel table, injectors, and boost table with the switch and be in race mode. The biggest question is can I kill the injector ground with a relay to switch between injector sets or is there a better way?  

[Adamw]

You would effectively need 8 switches to disconnect 8 injectors from the common power supply.  You would be better to have two injector sublooms connected via a single plug, when you want to run the 2nd fuel you unplug one injector loom and plug in the other.

[exileperformance]

I was thinking of the injector wiring backwards and maybe I'm still wrong please help... Are all the injectors tied together and supplied with 12+ volts and then individually fired by a signal ground? What would the draw back be of splitting the signal wire off and sending it to both injectors (for each cylinder) and just controlling the main power to the injector. I could have a DI input switch setup so when it is off fuel table 1 is active boost table 1 is active and my gp output for relay that controls gasoline injector relay is on. Then is DI switch is on fuel table 2 and boost table 2 is active along with the gp output for the Methanol injector relay. Maybe this isn't possible, I'm looking to set it up so it is seamless and can switch on the fly. Is this possible or will I have issues?

[Ducie54]

What's wrong with using multi fuel modeled mode. Are you using 8 or 16 injectors?

[Adamw]

11 hours ago, exileperformance said:

I was thinking of the injector wiring backwards and maybe I'm still wrong please help... Are all the injectors tied together and supplied with 12+ volts and then individually fired by a signal ground? What would the draw back be of splitting the signal wire off and sending it to both injectors (for each cylinder) and just controlling the main power to the injector. I could have a DI input switch setup so when it is off fuel table 1 is active boost table 1 is active and my gp output for relay that controls gasoline injector relay is on. Then is DI switch is on fuel table 2 and boost table 2 is active along with the gp output for the Methanol injector relay. Maybe this isn't possible, I'm looking to set it up so it is seamless and can switch on the fly. Is this possible or will I have issues?

Yes, injectors are supplied a common +12V source and the ECU grounds each injector individually.  Here is a example of what I think you are proposing (only 4cyl to save time):

In this pic above my switch is only supplying 12V to the "B" injectors so you would think only the B injectors are getting power. 

But here's what happens for instance when injector drive 1 is grounded but Inj drive 2 isnt:

As expected current will take the green path, flow from the switch, through the blue wire, through injector 1B to the ECU inj 1 drive (injector 1B will be on):

But if you think about it more, there is also a path through 1A, 2A & 2B as 2B is also connected to 12V and in a round about way back to Inj drive 1 at the same time (magenta path).  These possibly wont have enough current going through them to make them open but they are certainly going to be doing weird stuff like closing slower etc.

[exileperformance]

Ok that makes sense, thank you! 

13 hours ago, Ducie54 said:

What's wrong with using multi fuel modeled mode. Are you using 8 or 16 injectors?

I will be using 16 injectors