jimmyblue

iTrader: (11)

Been looking at the numbers they have for each injector
with an eye to determining injector offset table corrections,
but the numbers just do not make sense. For example a
42# Lucas lists:

Part Number Delphi 01D030B (Lucas old 5208009, Lucas New 621031, Delphi old D3181AA)
Static Flow Rate: 42.29 lb/hr @ 43.5PSI (300kPa) or 320gm/min
Static Flow Rate: 48.83 lb/hr @ 58.0PSI (300kPa) or 370gm/min
Dynamic Flow Rate: 9.96 gm/pulse - 2.5ms pulse width and 10ms repetition rate @ 43.5PSI

Now,

9.96gm/pulse * 100 pulse/sec * 60sec/min * 2.5mS/10mS duty

gives me a delivered fuel of 14940 gm/min. That is just so
whacked I don't know where to look, for the error. It says
pulsed flow corrected for 25% duty is a nice, round, 1500X
the static flow. Like, that's 25*60, but why?

Does anyone understand these numbers?

http://www.racetronix.com/621031.html

Runn

Put your time on these instead http://www.racetronix.com/17113738FM.html Just kidding i know that you seen my thread on hptuners.

I lowered the offset 30% and now they are better, but it would be nice with exact numbers.

askulte

Those numbers don't work, and I can't figure out where they came from. If you take a 42.29 lb/hr injector, that works out to be 5.33 grams/second. Multiply that by .0025 seconds (2.5 milliseconds), and you get .01332 grams/pulse.

Their dynamic pulse numbers were all 100x too large for the MSD/Holley 55 lb/hr injectors. The steady flow of 6.93 grams/second matches 55 lb/hr. The dynamic lists 1.34 grams/pulse, but actually .0134 g/pulse works. In that case, 100% flow for 2.5ms would be 1.733mg, so this is 23% less, or effectively .566ms less duration.

6.93g/sec * .0025sec = .0173 g/pulse
(.0173-.0134)/.0173 = 23% * .0025sec = .000575 sec offset, or .575ms

It's odd that many of the numbers they list don't make sense, and the rest do, if you divide by 100. <shrug> It's still a huge help, being able to get real numbers. Most of the LowZ injectors seem to have .55ms to .65ms offset. What's interesting is the Delphi 50 lb HighZ injectors have only a .75ms offset, only .1ms longer than the lowZ's.

I've been going through all this with trying to remap the DFI6 fuel maps in Excel, since that doesn't even have injector offsets or sizes - just a 16x16 map for raw injector pulsewidths.