just something a bit more high tech than a resistor-box....


The graph, clearly demonstrating the peak&hold method of engaging the injector


I'm very pleased with how this little project is turning out... will be installing on the car soon, to see if it performs as advertized.

 

nice, care to share the circuit diagram?

 

I'm using the one in the spec sheet for the lm1949, with a couple of additions, just adding voltage regulation to give the chip a steady 5v to run from. I also fiddled a bit with the cap values, to get the graph nice and the spike a bit higher than it was with the values in the spec-sheet... this is very dependant on the injectors though, so I would recommend fine-tuning with the ones you plan on running....

 

what does this do?

 

Just installed it and the injectors today.... and to my utter surprise, the car started up first crank, not withstanding the fact that it's a rather major alteration..... some quick mapping to get the AFR's back into shape, did a couple of runs and in less than half an hour we had fuel capacity for way over 1.5bars boost.


ECU running much cooler than without the driver, and even the driver itself does not get very hot...


what this does, It spikes the injector with an initial burst of current, getting it to pull open very fast and very accurate.... once the injector is open, it does not need all that current to stay open, less than 25% of it, is usually way more than enough to keep it there.....

Problem with driving a Low impedance injector with it's full current, is that when the time comes for it to shut down, the magnetic field collapsing, generates considerable back-EMF, and that in effect, will try to keep it open, causing a very delayed and crappy shut-slope.

With the peak and hold method, the hold current being much lower, limits the back-EMF, and thus give the injector the ability to shut down much faster as well, so it's a win win win situation.... fast and strong open, fast close, and much easier on the ECU....

 

VERY nice!!