How involved is it to add another set of injector drivers to an ecm, or even to use external drivers. I need the ability to use 4 tbi peak and holds for a custom project. Thanks. It would be really nice if I could use a tbi truck ecm and just add another set of injector drivers.

 

To date the only option is one of the ACCEL optional drivers boxes. and they were expensive. No EE has taken the challenge of doing a MOSFET driver, setup and seeing how long it would last. least as far as I know.

 

There are a few schematics floating around for the circuit you need. It uses a chip that may or may not be obsolete right now. I did get a couple samples awhile back(< 1 yr), but never got it going due to other stuff going on. The chip is the LM1949, and uses about 7 other parts to make work. This is the same circuit used in the GM ecms. You could get some spare ecms and take the whole circuit out, but you have to be good with a soldering iron. Other than that, its like grumpy said, nothing else too much available, or expensive. The part is from National Semiconductor, it couldn't hurt to try any of the electronic distributors to see if they might have stock, like newark or jdr, or digi-key. HTH

 

What I was thinking was taking two ecms and attempting to parrallel the drivers out of one into another. I was just wondering if this is possible because I did not know how they are wired, and driven within the ecm. I may just get two out of the junkyard, gut one, and see what I can find out.
The reason I am asking is a friend is intersted in putting an old style blower on his 57, and wants it to look nostalgic. Due to the "look" he wants to achieve, it is not practical to mount a air temp sensor and a map sensor downstream of the blower, so using a 749 ecm would be a waste, and I don't think it has the guts to drive 4 tbi peak and holds anyway. So what we want to do is use two truck tbi units (which look alot like carbs with the air cleaner). Since a roots blower is positive displacement, the boost vs. pre boosted pressure will always be the same (not changing with rpm much). It will be a pain to tune, but it would work I think, if I can just get this injector driver thing taken care of. Thanks for the replys.

 

you could just build a simple high current driver board and run 4 pnp transistors. i could hunt for a part # but it wouldn't be hard.
or build a board with 2 trnasitors for 2 throttle bodies cuase i think the 747 fires the injetcors like batch. not sure on this one. anyways a few lm713 or the like could be had to make work as a voltage regulator and then a few i dont know pnp NTE27's as the drivers. . not really hard to do. im not an electronics engineer but what yr trying to accomplish cant be that tough. what yr basically looking to do is aviod excess cureent draw. so what yr end goal should be is to build a high current swtiching board. no commutation just current delivery.

not a really tough circut. just look for something like a high current switching circuts. hell any high power stereo ampliefier circut should work for you. just the dc ouput side anyways.