# Thread: Correct IFR tables for LS3/LS7 injectors in Gen III

1. Originally Posted by dian
on second thought, i have no idea what the labels are on the l96. i thought thay were hektopascals. just curious.
I'm not sure what you mean...?

The axis is on kPa...

post a screenshot of what you're seeing.

~ posted by phone ~

2. under l96 i see labels from 128 to 768. the values in the tables are different. but i probably misunderstend something.

3. Originally Posted by Whipped383
Attachment 20465

This appears to be the correct file for the injectors in question
Originally Posted by dian
under l96 i see labels from 128 to 768. the values in the tables are different. but i probably misunderstend something.
In the tune file attached to post #132 above, the axis of table B4001 has those labels.

Those labels are injector pressure delta (difference from top to bottom of injector) in kPa.

4. So if rail pressure measures 400 kPa (58 psi) (i.e. gauge pressure is 400 kPa, so absolute pressure is 500 kPa)

then injector pressure delta = 500 - MAP

so then the usable range of the axis on B4001 are as follows:

• NA: 408 to 468 kPa (400 kPa has to be interpolated by ECM)
• 1-bar boost: 308 to 468 kPa
• 2-bar boost: 208 to 468 kPa

5. Originally Posted by joecar
In the spreadsheets, the LS1B paste-able tables are labelled.
The tables in these spreadsheets are great, but don't the numbers only work if the Fuel Rail Pressure is 58 psi?

Is there a conversion possible to use LS3 injector data at a different Fuel Rail Pressure? Say... 44 psi?

6. Yes 58 psi.

You can scale the IFR table using by multiplying by sqrt(44/58).

7. Originally Posted by joecar
Yes 58 psi.

You can scale the IFR table using by multiplying by sqrt(44/58).
That makes a large difference. Thanks for the formula!

58 to 44 is a 12.9% difference.

Can rail pressure affect Minimum Injector Pulse Width? I realize it's a measure of opening time, but it seems like the volume injected at a lower pressure would be less within that time and a compensation could be to modify that minimum time.

8. Originally Posted by spedracr93
That makes a large difference. Thanks for the formula!

58 to 44 is a 12.9% difference.
Yes, scales by 0.871.

Can rail pressure affect Minimum Injector Pulse Width? I realize it's a measure of opening time, but it seems like the volume injected at a lower pressure would be less within that time and a compensation could be to modify that minimum time.
It can... I don't know how to calculate the new minimum.

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