----- Original Message -----

From: Bulent Aliev

Sent: Friday, May 07, 2004 7:54 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: fuel injector prices

 

On 5/6/04 11:31 PM, "John Slade" <sladerj@bellsouth.net> wrote:

>>   550 cc/min = 0.1453 Gallons.  So 0.1453 Gallons * 60 (minutes) = 8.718
>> Gallons/ hour x 6 (lbs/gallon) = 52 lbs/ hr.  Or a 550 cc/min
>> injector would
>> flow approx 52 lbs of fuel if it flowed wide open for one hour or
>> 52 lbs/hr.
>>
>> for the NA engines the stock injector is the 460 cc/min (sometimes they
>> varied a bit around that figure)
>> 460 cc/min =  0.1215191gallons so performing the same
>> calculations = 7.29114
>> gallons/hr x 6 = 43.75 lbs/hour
>
> Ed.
> Thanks. I follow that So with 4 of these 550cc suckers going full belt I'd
> be capable of expelling  52/6 * 4 = 34.67 gals/hr. Seems a bit excessive!
> Also - does fuel pressure factor into the equasion?
> John

John, I believe it does. If the EC2 controls only the pulse length, Higher
pressure will expel larger quantity of fuel than lower pressure for the same
injector opening. I don't think the EC2 takes into account the capacity of
the injector?
Bulent

Yes, pressure will definitely affect flow rate.  There is a standard pressure that is used (40 psi I think) to spec injectors at.  Mazda regulators put out between 35 - 40 psi depending on manifold pressure.

An EFI system that didn't take into account the injector flow rate would be doomed to failure.   Mode 3 on the EC2 is there to compensate for differences in flow rate.  There is always a limit to how much can be compensated for, of course.

Tracy