injector flow rate backwords?

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May 23, 2006 | 01:19 PM

xclr8ingc5

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injector flow rate backwords?

Hi, I have a 1999 c5 with a head and cam package with a tune from
cartek. However i have had fueling problems since it was installed and
decided to get ls1 edit some time ago before hp was available of course.

Question? I recently suspected the injectors as part of my inconsistent
fueling and decided to do some homework. I am still running the stock 26#s
and thought they might be the problem or part of. I found the injector flow
calculator in the stickys and input my stock numbers and to my suprise it
spit out the identical numbers however when comparing to my tune it looks
as though my values gm/sec are put in backwords under kpa values.

for example: at 20kpa 3.65gm/sec and at 100kpa 3.33gm/sec
injector flow rate calculator shows same values but gm/sec increases with
kpa not decrease?

I am not a seasoned tuner but this doesnt appear right but instead looks
like values are reversed. Unless I am missing something with the way ls1
edit works or dont understand what I am looking at I would assume this is
a big part of my problem.

Please give me any input or let me know if I am correct on this so I can
correct my tune or learn something new.

Thanks,
xclr8ing c5

May 23, 2006 | 01:36 PM

jimmyblue

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From: East Central Florida

Table basis is kPa -vacuum- in most tools (BARO-MAP).
But I vaguely recall Edit may be opposite from others?

May 23, 2006 | 01:42 PM

SSpdDmon

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From: Commerce Twp, MI

EFI Live's take on this is....

Quote:

Flow rate of the fuel injectors.
If the fuel rail pressure is NOT referenced to manifold pressure, then decreasing the manifold pressure has the same effect as increasing the fuel rail pressure. The fuel flow rate of the injectors will increase at higher manifold vacuums (i.e. lower manifold pressure).

This table calibrates the flow rate of the injectors at various manifold VACUUM levels.
It is based on manifold absolute VACUUM, where:
0 kPa vacuum indicates atmosphere and
80 kPa vacuum indicates atmosphere less 80kPa which, at sea level, is 101.3-80 = 21.3 kPa MAP.

IFR shows 3.328125 grams per second at WOT (sea level) and 3.648438 at a MAP equal to 21.3kPa for stock 26lbers.

Last edited by SSpdDmon; May 23, 2006 at 01:48 PM.

May 23, 2006 | 09:38 PM

xclr8ingc5

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EFI Live

I understand and that makes sense why my table goes 20 to 100kpa
instead of 0 to 80kpa. However I would like to add bigger injectors and
it looks like I would need to adjust injector flow rate and injector offset with
Ls1 edit. where would I find a calculator for ls1 edit for offset and flow rate?
Also are there files or charts available for me to look at to adjust accordingly.
I am thinking of going to a 28# gm injector from a ls1. I can buy a set very
cheap and with my combo and elevation it should work fine.
When I make a major combo change or power adder I will upgrade the fuel
system accordingly. I live in great falls, MT and am at 3800ft and a normal
day at the track is about 5500 to 6500 density altitude. My combo should
produce around 420 rwhp, so 28#s should work for awhile.

Thanks for help and any other input is appreciated,
xclr8ingc5

May 23, 2006 | 09:52 PM

SSpdDmon

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From: Commerce Twp, MI

I'd say, see if you can find a copy of a stock '02 tune and take the IFR settings from there. I'm not sure how Edit works vs EFI or HPT, but that's what we end up doing for the 26lber to 28lber swap.

May 23, 2006 | 10:32 PM

slow

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From: Orlando

Are you talking about the Excel spreadsheet, I noticed the same thing last week, was like "wtf" how are my injectors flowing more at wot, as the spreadsheet appeared to be backwards.

Ryan

May 23, 2006 | 10:38 PM

xclr8ingc5

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injector swap

well that makes sense and I am feeling really outdated running Ls1 edit.
Is there no Ls1 edit files in this forum? I see plenty of Efi live and hp files.
It is appearing like I will have to convert one of those tune files. Unless
someone knows where I can find a stock tune file with ls1 edit for 2000 or
newer ls1 so I can run 28#s instead of 1999 26#s.

If anyone knows where to find or make it easy for me that would be cool!