In reply to fidelity101 (Forum Supporter) :
There is an Ace Hardware across from where I work that has the hugest selection of nuts and bolts and screws as I have ever seen. If they don't got it, it don't exist.
Updates... So I had it my head to want to try to properly characterize my injectors, which are modified Bosch units that were claimed to be 1200cc/min. I never could get them to idle or cruise well, and it would run lean or rich with air temperature changes, a sign that the deadtime was way off. After too much thought, I decided to switch the firmware (MS2/Extra) to incorporate AFR table, then change the AFR table to see if the calculations were undershooting or overshooting.
BUT, and this is where the "too much thought" comes in, this would only be accurate if I had the SIZE correct in the calculations, so I would have to run the AFR switching at different pulsewidths too, so I could not only get the "zero point" correct but also the "gain". This would be remarkably difficult to do in a stationary environment as it seems like at any kind of idle or free rev the injector pulsewidth stays the same, no matter the RPM. But then, I realized that I could run the injectors wide open in test mode into a large (60ml) graduated syringe that I had, to measure flow directly. Perfect.
So, I spent too much time rigging up a way to hold the injectors in the rail (where DID my giant bag of zip ties go?) and did some math. I want to know cc per minute. A cubic centimeter is a milliliter, conveniently enough. If I ran the injectors for 26 milliseconds on a 25 millisecond interval, that is 100% duty cycle guaranteed. 4 pulses would be a tenth of a second, 40 pulses would be one second, 120 pulses would be three seconds. Multiply the result by 20 and the result would be cc per minute. I set up the injector rig in my right hand, set up the laptop on the wiper cowl so I could click buttons with my left hand, and tested an injector.
To my surprise, the injector had a beautiful spray pattern instead of just squirting like a hose like a lot of huge injectors, so it foamed up in the syringe and half of it ran out all over my hand in the engine bay. Oops.
Okay, let's cut it down to 60 pulses and we will multiply by 40. I was not thrilled with this as the less fuel is measured, the more any measurement error would be multiplied, and I was not exactly using a tightly calibrated device. But as it turns out it was good enough.
First injector, 24ml, repeated twice. 24ml times 40 is 960cc/min, significantly less than advertised even taking into account that I am running at 2.5 bar pressure and not 3 bar like injectors are rated at. (Because that was how Mazda rolled in 1982 when they started injecting rotaries)
Second injector, 22 ml, repeated three times, and switched back to the first injector to verify that I was measuring THAT one correctly. 22ml times 40 is 880cc/min. That's roughly 8% less flow. THAT is why I could never get it to idle right, or had to make it run what seemed like amazingly rich under cruise to keep it from stuttering and lean-missing. Because of the long primary exhaust system, I could measure only one rotor, and I probably had the wideband in the tube fed by the larger of the two injectors.
Well, berk.
Time for another hunt.... and found my good old GSL-SE injectors from way back when I started playing with injection in 2008 and picked up a GSL-SE engine complete for like $200. (Because it was 2008 and they were worthless) Cleaned them up as best as I could, decided to try to characterize them too because turd polishing knows no bounds. Man these old style injectors are huge compared to modern pencil injectors. Got them in the rig (where ARE my zip ties?), holding the rig in my right hand, turn on the fuel pump with the mouse with my left hand, and it blew one of the injectors out and started hosing pretty blue gasoline everywere. And I am very right handed and can't mouse with my left.
Fine, whatever, I won't characterize them. Open the garage door, set up a fan to blow as many fumes out as possible, go outside to clean up with GoJo and bottled water...
