swinke

My E-Manage says that I am at 100% duty cycle on my Z in the high R's. More specifically it says that 19.3ms is 100% duty cycle at 6500rpm. Does anyone know what the 100% duty cycle time in "ms" is at 6500rpm on a 6cyl engine? Should just be a math problem, right?

John at J&S

For a six cylinder engine, the time between spark events is 20/RPM. All six plugs will fire in 6*20/RPM, which is two revolutions, or 720°.

If we assume full sequential injection, each injector will fire once every 720°.

At 6500 RPM, this is 18.46 msec., BUT you must deduct the time reqired to open and close the injector.

A good rule of thumb is count on no more than 80% of the available time, or about 14.8msec.

swinke

So I need bigger injectors anyway? Or should I just turn up the PSI on the DFMU and retune the injector cycle at the lower RPM to compensate for the extra fuel? The way you describe it I am out of injector cycle window to increase fuel with the E-Manage.

John at J&S

Three choices:

Bigger injectors, raise the fuel pressure, or add extra injectors.

swinke

John,

Yer my hero!

Thanks again!

I really wish you would cook up a Safeguard with 6 channels for me! How much$$$?

swinke

ps; Look at all the business you’d get with the V-10 and V-12 crowd with a 6 channel Safeguard!

(best attempt to goad you into something that’s not profitable)