Injector duty cycles

[Mazda Ebrahimi]

Roger Feingold wrote:
> 
> Thanks for your answer. I got different numbers than you, but I still was
> wondering if anyone had some test data. I figured 467cc of air per cylinder
> per intake stroke. At 5k rpm that's 25.3g/s. 12.6:1 A/F is 2g/s of fuel.
> 2x60x60/454 = 15.86 lb/hr. This assumes 100% VE. At 6k rpm would be even
> higher, 19.11 lb/hr, this is why I thought it would be maxed out.
> 
> Roger.

Hi Roger,

The peak efficiency number that is always thrown around conversations is 
80% (and that is at peak torque which is at a lower RPM).  There are 
some trick production engines that easily top 80%, but I don't know if 
the 2.8L is one of them.  At any rate, my point is that after peak 
torque, your VE goes down, and from what I remember of my '88 Beretta 
with the 2.8 MPFI, power drops drastically past 5500 RPM.  
I have a chassis dyno, but unfortunately I sold my Beretta last year, so 
I can't be of any assistance.

Best Regards, Mazda