How to run 75 lb/hr injectors with the GM PCM
By late 2001 all of my DataMaster logs showed that the MSD 50 lb/hr fuel injectors were max'ed out. The PCM was commanding duty cycles way over 100%, and the resulting O2 numbers were in the 800s. Not good! And this was with extremely high fuel pressure - about 62 psi static (with no manifold pressure supplied to the regulator) and 72-73 psi at full boost. The car needed bigger injectors, but the MSD 50s are the biggest high impedance injector available, and the PCM will *not* run low impedance (or low-Z, because 'zee' is the symbol used in electronics for impedance) injectors. You will let the smoke out of it if you try!
So the engine needed 75 lb/hr injectors, and I needed a box that would enable my PCM to run them (since I didn't feel like spending kilobux on an aftermarket engine computer that wouldn't make my car any faster). Somebody needed to design something, so I did.
Introducing the AcceleronicsTM Impedance Converter
The AcceleronicsTM Impedance Converter splices in between the PCM and the fuel injectors to provide both the high current capacity and the peak-and-hold logic needed to run low-Z injectors. The picture below shows my prototype in place on top of the intake manifold. It's driving 75 lb/hr injectors, and doing a mighty fine job of it! The car runs *much* better with the low impedance injectors and normal fuel pressure than it did on the overstressed 50's. Idle quality is great with 1.4 ms pulsewidths. These big squirters are *very* streetable.
The prototype works so well that I decided to form a company to build and sell Impedance Converters. Surf on over to http://www.acceleronics.com.