Fuel Injector Question

[Lowend]

A question that has bothered me for awhile



When you go to a higher flow injector have does it work?
Do you get larger fuel droplets, or just more of the the same size that comes in a smaller injector?

I'm contemplating if there would be benefits in using 2x20lbs injectors instead of one 40lbs injector (just an example).
Small droplets would be more efficient... yes?

[Lowend]

anyone??

[Twentyover]

Don't know, but I'd suspect they would upsize the pintle and orfice. With goo design, the spray size shouldn't be substantially larger than with a smaller orfice

[gkring]

Use the smallest injector possible to get your horsepower levels with a little cushion left over. The only time you should conside dual injectors would be a staged setup where you need so much injector on the top end that you can not get a good idle because the injector just can't get a pulsewidth short enough that is controlable. Even then you stage them, but I see no reason to run double injectors at the same time, especially in that small of a range. I ran 160 pound an hour injectors in my GN with no problems. I also used bank to bank as well as the sequential FAST computers with no noticeable benefits to either. Good luck.

[86Cutlass383SR]

I am no EFI expert but I have been doing some reading up on it. If I understand things correctly, You would be better off using a somewhat smaller injector at a higher pressure than a larger inj at a lower pressure. Using you 40# inj as an example, it will flow 40# of fuel at a measured pressure. At a lower pressure it will flow less and higher pressure it will flow more. Using a lower pressure to fix a rich condition results in the fuel not being atomized as well. I'm guessing the lesser atomized fuel would have a larger droplet size and less efficient burn. I believe in a case like this it would be better to use a 30 - 36 pound inj at a higher pressure to reach at desired fuel flow and better atomization. You also want the duty cycle of about 80%. Any more duty cycle may lean you out (from maxing the inj and not being able to supply any more fuel) and any less starts affecting the atomization.

If any one else knows if my ideas are wrong, please let me know.

Doug

[Lowend]

I was just using the 40# as an example; I am aware that running higher pressure will make the injectors more efficient, let's assume this is already done.

This is a maximum efficiency model