I read that people have used SSR's to drive additional fuel injectors using the signal from existsing injectors. I thought the injectors get a full 12v from the ECU then they get a lower holding volatge for the duration of the pulse.
Having a constant 12v from the SSR to the injector, would this not burn out the injector?, I know cold start injectors run on a full 12v, for GSXR600 k6 fuel injectors? thanks

 

I've not read that. Sounds like a bad idea on the surface. Injectors are just on/off devices. Feed them 12V+ then ground them and they open. Peak and Hold as you are describing don't vary the voltage. Some ECUs might taper off amperage after they are open, but voltage is constant.

 

6th post down, hes on about SSR to drive an injectors, https://www.theturboforums.com/threads/9th-injector-to-inject-e85-into-air-charge.364356/page-2

 

Try it out and report back. I like the theory. Be nice to see how it works in practice.

 

Fuel injectors get constant 12v any time the ignition is on and all the controlling is through the ground. Seams like I spent quite a bit of time looking into the solid state option you were describing a few years ago and after more research ended up deciding it would not work.

Relays would only work to switch between injectors not control signal. They could also be used to activate additional injectors but not to control the signal side. I am currently running 20 injectors but use 8 dual pole relays to switch (not control) the signal side of the injectors between the 2 sets of 8. (Dual fuel application). Then my ECU has a 9th and 10th injector driver built in and these are split (signal side -) to the additional 4 injectors for my supplementary injectors. This setup has been working flawlessly for about 2 years. Prior to this I was using diodes on every injector which allowed me to switch between the sets of injectors using just one relay turning the 12v power side on or off to each set by just switching the power feed with a single dual pole relay. This worked for the most part but proved to be unreliable over time as diodes kept failing . Without the diodes the power would back feed and fire the other injectors in an undesirable fashion as I learned from experience.

I think your best option (providing you have a pile of cash laying around) would be to get an aftermarket additional injector controller or you could split the signal side (ground) to a second injector off each original injector but it wouldn't work without diodes unless you intend to run every injector all the time or have an ECU with more drivers than you are currently using. Using diodes on every injector is a lot wiring and a tedious undertaking. A Hobbs switch would work or if you have an aftermarket ECU like a Megasquirt there would be lots of ways to activate the second relay or relays or additional drivers at a desired load, boost level, rpm, etc. Remember though the additional injectors not having their own independent drivers need diodes employed on each one unless you intend to run every one of them all the time. By far the easiest would be to have additional injector driver capabilities built into your ECU by having an MS3Pro like I have or similar after market piece or you will run into the same issues I did. Also you would really need supplementary injector fueling tables etc that would not be possible to tune in any precise way I would trust my engine without an aftermarket ECU that is set up for that. Just my two cents from having messed around a lot of hours with my own setup and also wasted a lot of time with trial and much error, somebody else may prove me wrong.

 

Sorry only just seen your reply, great info thanks very much!

 

Can you show a sketch of how you did this? I think I understand, but just want to make sure. I'm also looking at doing a dual fuel (gas for street cruising and automatically switching to 100% ethanol in boost) but can't find much info. I saw the setup with the diodes, but am not particularly charmed by using them.

 

Very interested I have been thinking of adding an 7th and 8th alc injector into my screw style blower (sorry not turbo) intake mostly for cooling ( already have an WAIC) and if lucky a pound or two more boost. I am thinking i can split the ground signal from 2 of the normal inj and supply 12V power by installing 2 adj hob switch's installed in the intake plenum set to come on at different boost levels. Thinking first one around 12lb and the 2nd 17lb. Anyway all of my inj are high imp style if that means anything but i am worried that tying the inj ground together might hurt my ecu. Is an SSR ???? mention at first something that is used or needed to protect the ecu.