LS1 Edit Injector Scaling

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Mar 13, 2002 | 01:21 PM

Black LS1 T/A

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From: Raleigh, NC

Re: LS1 Edit Injector Scaling

Great info!

Mar 13, 2002 | 02:07 PM

Chris Jones

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Re: LS1 Edit Injector Scaling

My numbers for 30# SVO were a little off I think. Any idea how to figure out what the injector offset for 30# SVO's should be?

Mar 13, 2002 | 02:15 PM

Phate

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Re: LS1 Edit Injector Scaling

How about an entry for my MSD 50# injectors? Also, I think a lot of people (especially those with the Vortech kit) are running Lucas 38# injectors.

Thanks Jeremy,

Scott

Mar 13, 2002 | 02:30 PM

Godspeed

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From: Godspeed

Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr />My numbers for 30# SVO were a little off I think. Any idea how to figure out what the injector offset for 30# SVO's should be? <hr /></blockquote>Numbers will be different depending on how many decimal places you use for accuracy. For stock injectors are you using 28# or 28.6#. Being consistent on how many decimal places you hold and how you round your numbers are key.

Regarding the injector offset, I belive the SVO injectors are slower than the GM injectors. The injector offset is expressed in (ms) in the PCM and is the time delay for opening the injector. I would think that you would need to decrease the injector offset for the SVO's. I'll see if I can come up with a better answer for you.

[ March 14, 2002, 07:37 AM: Message edited by: Godspeed ]

Mar 13, 2002 | 02:31 PM

Godspeed

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From: Godspeed

Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr />How about an entry for my MSD 50# injectors? Also, I think a lot of people (especially those with the Vortech kit) are running Lucas 38# injectors.

Thanks Jeremy,

Scott <hr /></blockquote>Thanks, I added them.

-Jeremy

[ March 13, 2002, 04:34 PM: Message edited by: Godspeed ]

Mar 13, 2002 | 03:10 PM

Black LS1 T/A

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From: Raleigh, NC

Re: LS1 Edit Injector Scaling

Jason (GWP) is going to put 50# Injectors in my 383 as well. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Mar 13, 2002 | 04:51 PM

DUKE

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Re: LS1 Edit Injector Scaling

Godspeed....you da man! Thanks <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

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Mar 13, 2002 | 04:59 PM

Godspeed

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From: Godspeed

Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr />Godspeed....you da man! Thanks <hr /></blockquote>I like to do what I can do when I can do it. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

-Jeremy

Mar 13, 2002 | 05:22 PM

#10

Godspeed

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From: Godspeed

Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr />if the correction factor is 1.385, them you multiply by 101.385%. Is this correcto mumo? <hr /></blockquote>The Injector Flow Rate table contains the flow rate in grams per second (gm/s), as a function of the intake manifold Vacuum (Kpa.)

Percent (%) is expressed as a fraction of 1.00, so 1.385 would be 138.50%. Multipling by 101.385% would only increase the values by 1.385% - off by two decimal places. Multiply all the cells in the table by the correction factors I have listed, not as a percentage.

Some of the larger injectors actually flow twice as much as the stock injectors, giving us a large correction factor of over 200%. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

-Jeremy

[ March 14, 2002, 07:38 AM: Message edited by: Godspeed ]

Mar 13, 2002 | 05:31 PM

#11

sross

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Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr />Originally posted by Chris Jones:
My numbers for 30# SVO were a little off I think. Any idea how to figure out what the injector offset for 30# SVO's should be?<hr /></blockquote>I don't think the SVO injectors are rated at 39 psi. I heard that about 5 years ago (and several times since) but I think they're rated at the "standard" 43.5 psi. Try using 1.33 for your correction factor. That should get you better numbers. At least it did for me.

Please give us an update.

<blockquote>quote:<hr />Originally posted by Duke:

Now let me get this straight. Actually, when you say multiply the table by the correction factor: if the correction factor is 1.385, them you multiply by 101.385%. Is this correcto mumo?
<hr /></blockquote>Close. You want to multiply the entire table by 138.5%.

[ March 13, 2002, 05:32 PM: Message edited by: sross ]

Mar 13, 2002 | 05:45 PM

#12

Godspeed

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From: Godspeed

Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr /> don't think the SVO injectors are rated at 39 psi. I heard that about 5 years ago (and several times since) but I think they're rated at the "standard" 43.5 psi. Try using 1.33 for your correction factor. That should get you better numbers. At least it did for me.<hr /></blockquote>Well crapola, I was on the 43.5 psi wagon for a long time, but was recently convinced otherwise. When I ran a set of SVO 42's in my twin turbo LS1, I did my personal calculations based off of 43.5, although Ed actually tuned it. My calculations seemed very accurate, but I've seen so many people swear it is 39psi.

I may just list both 39psi and 43.5psi in the chart until I can confirm for certain which is true. Hell, I may just have a set of SVO's flowed, so I will know for sure.

-Jeremy

[ March 14, 2002, 07:29 AM: Message edited by: Godspeed ]

Mar 13, 2002 | 06:17 PM

#13

Godspeed

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From: Godspeed

Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr />Please give us an update<hr /></blockquote>Updated. I listed both, though personally I think the SVO's are rated at the standard 3bar - 43.5 psi. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

-Jeremy

[ March 14, 2002, 07:40 AM: Message edited by: Godspeed ]

Mar 13, 2002 | 06:19 PM

#14

Pro Stock John

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Re: LS1 Edit Injector Scaling

I am running Bosch injectors, OE from a 2000 GTP Grand Prix...

John,
According to Harlan (in an injector thread on LS1Tech.com), your
injectors are Delphi 37lb at 3.5 bar which makes them 39.55077lb injectors
at 58PSI (4 Bar) NOT 38lb injectors... So....

According to my math, you would use the following table for LS1Edit for your
injectors. Since they are a Delphi Injectors thus Multitec 2's, they
probably have the same or similar flow curve as our stockers so we can use
the stock injector math as a reference. Have Brian at BV try this table
if he hasn't already calculated it on his own, so far the numbers I've been
able to generate when given accurate info about the injectors have been
pretty accurate.

KPA 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

New Injector Flow using Reference Curve 4.96 4.98 5.02 5.05 5.08 5.10 5.13
5.16 5.19 5.21 5.24 5.27 5.30 5.32 5.34 5.37 5.39

The numbers starting with 4.96 for 0 Kpa get put into LS1 edit in the Fuel
Injector table.
John@PACE

[ March 14, 2002, 02:52 PM: Message edited by: Pro Stock John ]

Mar 13, 2002 | 06:41 PM

#15

DUKE

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From: ALABAMA

Re: LS1 Edit Injector Scaling

Godspeed...you're not only da man! You're da super man. I see that calculation light now. Thanks <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" />

Mar 13, 2002 | 08:20 PM

#16

Godspeed

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From: Godspeed

Re: LS1 Edit Injector Scaling

<blockquote>quote:<hr />I am running Bosch injectors, OE from a 2000 GTP Grand Prix...
<hr /></blockquote>Thanks, I'll update the info. Perhaps I should just do all the calculations for the table as well. Hmmm...

-Jeremy

Mar 14, 2002 | 12:35 AM

#17

Godspeed

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From: Godspeed

LS1 Edit Injector Scaling

I made a simple document with charts to help correct for injector swap outs. Use my numbers at your own risk. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

HTML Version

Excel Version

Acrobat Version

-Jeremy

[ March 13, 2002, 09:37 PM: Message edited by: Godspeed ]

Mar 14, 2002 | 11:02 AM

#18

Reckless

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Re: LS1 Edit Injector Scaling

Next question:

If you are able to adjust your fuel pressure and you are running SVO injectors, couldn't you just lower the FP to 43psi and then just do the math for the difference?

That is, I have SVO 42lb injectors, and my FP is set to 43psi, so:

42/28.6 = 1.43 (CF)

I can just use this CF throughout my tables if I set my FP at 43, right?

To further confuse the issue, I want to run my FP at 50psi because the TNT wet kit is jetter for 50 psi, so I do a new flow rate that looks like:

new rate = sqrt(new psi/old psi) x old rate
= sqrt(50/43.5) x 42
= 1.072112 x 42
new flow rate @ 50psi = 45.03

the 45.03/28.6 = 1.57cf

So the CF for 42lb SVO injectors at 50psi would be 1.57? I think this is right?

OBTW...the table is great! I printed it for my LS1 Edit Binder. I am compiling everything I can, so when questions come up, I will hopefully have the answers <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

[ March 14, 2002, 11:17 AM: Message edited by: Reckless ]

Mar 14, 2002 | 01:15 PM

#19

ChrisB

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Re: LS1 Edit Injector Scaling

You can't use a common scaling factor for the correction (across the MAP range) because while the head pressure to the injector will remain constant at 4 bar the discharge pressure will increase or decrease with vacuum..

If you have a 48 psi of rail pressure and 10psi of vacuum you have a 58psi delta across the injector - so you need to use the manifold vacuum + the rail pressure in your correction factor -
and since the table is scaled vs. manifold vacuum the correction will not be constant.

http://www.speeddemonmotorsports.com...ectorscale.xls

that is a quick spreadsheet I typed up to automate the conversion

I think there may be a bug in LS1 Edit - in the scaling of the MAP sensor. It shows flow rate INCREASING as MAP goes up - but the higher the MAP the lower the manifold vacuum (since it measures absolute pressure). Injector flow should increase directly with manifold vacuum, so it should DECREASE with MAP value.

The spreadsheet works currently with the values as stored, and will be correct (just about) if the scaling is actually 80-0kpa. If it is 100-20kpa like I suspect or something else then it may need to be tweaked.

Mar 14, 2002 | 02:00 PM

#20

John@PACE

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Re: LS1 Edit Injector Scaling

42's are rated at 39psi by Bosch, correct?

Then at 50psi, your at 47.55564lbs

5.99201 g/sec

98 injector table shows 3.64g/sec which makes the 98 injectors more like 28.8 almost 28.9lb.

You'll have to fine tune of course, but I would do the math on g/sec as LS1Edit uses it. Doing the percentage on lbs would yield 6.01 g/sec

John

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