DIY_EFI Digest V4 #448

[Gary Derian]

This doesn't directly address the cold start issue but injecting onto a
closed valve provides better atomization because the puddle of fuel is hit
by hot exhaust just as the intake valve opens.

250 ft-lb of torque and only 111 hp at 6000 rpm?  That doesn't seem right.

Gary Derian <gderian at oh.verio.com>
>
> Based on the last dynamometer run,  we found we were at about 12ms at
> 6000RPM and pulling 111 HP and our goal is 125HP;  We've been able to
> get over 250ft/lbs Torque. This, at a little less than 75% duty cycle.
> As I understand the reason for 'the name of the game' is to provide a
> smooth unloaded idle.  Since we turn a prop idling at about 900RPM we
> have a little bit of a load so a slightly larger injector might keep me
> under 75%.  (I have a hardware limitation on pulse widths longer than
> 75% if I plan my injection at low rpm for the intake stroke).
>
> But,  injection is supposed to get rid of the need for a lot of the
> excess fuel because it's sprayed almost directly onto the intake valve.
> Spraying onto a closed intake valve when the engine is cold or just
> warming up doesn't seem logical for a low pollution fuel efficient
> engine.