Does anyone know what the minimum turn-on time is for a 440cc Denso high impedence injectors (OEM from an '88 NA RX-7)?

Or, is this something that can be found through experimentation?

Thanks!

The minimum on-time can be found experimentally without much trouble IF your engine idles rich with the injectors pegged against the minmum on-time. The procedure is to simple set your fuel so that it's held up against the minimum on-time with the minimum set to something sort of high (like 1.6ms). Slowly reduce the minimum on-time until the engine stumbles and goes lean. This will happen rather suddenly. But this procedure will only work if your injectors are big enough for the minimum on-time to be a big issue at idle.

With 440cc injectors, especially if you'r running sequential, will not likely have that problem. If that is the case, set the minimum on-time low (maybe .7ms) and tune steady idle to where the engine likes (warmed up of course). Then set the minimum to about .1-.2ms below that. You don't have to worry about excess fuel during coast down because the fuel will be cut off completely then anyway.

A properly set minimum on-time will save you a lot of headaches when trying to prevent sudden stalls pulling up to a light or into a parking space.