Injector Sizing: not dumb questions at all

[goflo at pacbell.net]

Without entering into the speculation re virtue/lack thereof, I say
again that improving torque at light throttle/low rpm IS the point, or
my point, anyway, 
as it allows the use of more cam than would otherwise be streetable.

Regards, Jack

Gary Derian wrote:
> 
> Thanks for your comments Greg,
> 
> The Hilborn and Enderle injection systems had very poor metering at anything
> other than full throttle, they went way rich.  They were replaced not
> because they had constant flow but because they had poor metering.  Both
> Rochester and Bosch had very good constant flow FI systems.  Earlier this
> year in "Automotive Engineering", SAE's magazine, there was an article
> examining fuel droplet size vs. injection timing.  The researchers found
> that droplet size was smaller when the fuel was injected onto a closed valve
> and the exhaust backflow hit it than it was when injected during the intake
> stroke.  Backflow is a fact of life and can be useful to atomize fuel.
> 
> The Lucas timed injection was indeed mechanical but at high rpm it was
> practically constant flow, similar to an EFI.
> 
> Your comment about using cylinder turbulence to cover sins is a bit strong.
> I'm not bent on committing sins, I just want to have an effective FI system
> that works and that I can afford.  Do you have any real evidence that
> injection timed to inject only during intake flow provides better torque and
> fuel consumption at anything other that light throttle and low rpm?  As
> intake dynamics change with rpm and intake pressure, how do you vary the
> injection stroke start and stop time to inject only while air is flowing
> into the cylinder?  You must vary fuel flow rate quite a lot, either with
> pressure, a variable flow injector or multiple injectors.  If air is allowed
> to enter the cylinder without fuel, you still need to use cylinder
> turbulence to mix it up, the same sin you accuse me of.
> 
> I agree with low compression/hot exhaust.  Its basic thermodynamics.
> 
> Gary Derian <gderian at cybergate.net>