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View Full Version : anyone have the greentop 42lb injectors



pdasterly
March 17th, 2009, 12:42 PM
looking for people with these injectors, i need to know what the flow rate of these are. the guy i bought them from said they should flow at 48lbs in a 98 ls1 z28

hquick
March 17th, 2009, 02:37 PM
Alot of descrepencies about these.
This info is from the 'other' forum and comes directly from a Ford engineer.

Here's Fords direct data for the Lightning "Green Top" 42# Injectors.

High Slope:

40.68031311035172 lb/hr

High slopes have more of an affect on part throttle and WOT. In comparison, this would be like zero to lower manifold vacuum on a GM.

Low Slope:

48.9612579345702 lb/hr

Low slopes have more of an affect on cranking, closed throttle, and idle. In comparison, this would be like higher manifold vacuum on a GM.

Ford uses a "slope breakpoint", based on pulsewidth measurement, to determine when to switch between the two slopes.

Keep in mind, those flow rates are at 39 psi. So to determine what they would be at 58 psi, use the following formula:

√(58 / 39) * x (where x = lb/hr flow rating)

i.e. 40.68031311035172 at 39 psi = 49.609629114916362955367516916071 at 58 psi, and 48.9612579345702 at 39 psi = 59.708238738105991000993802244979 at 58 psi.

Minimum Pulsewidth:

0.000400543212890625

(aka 0.400543212890625 ms)

Injector Compensation for Battery Voltage:


Code:
VOLT PW ms
15.99 0.71484375
15 0.71484375
14 0.7861328125
13 0.9033203125
12 1.03125
11 1.197265625
10 1.396484375
8 2.1181640625
6 4.6474609375
0 4.6474609375
0 4.6474609375
0 4.6474609375As for the "Short Pulse Adder", Ford doesn't have such, so I'm not too sure what to say here. My best guess would be to just zero out that table.

I have found numerous sites listing them as 42lb/hr at 39.15psi.

hquick
March 17th, 2009, 02:43 PM
I'm using 42lb @ 39.15psi and I'm running at 60psi rail pressure.
This equates to 6.551332 flat lined as my system is a return fuel system.

pdasterly
March 18th, 2009, 08:13 PM
thanks for the spreadsheet