Previous tune using IFR for smaller injectors than fitted

[stigmundfreud]

Guys

just been working through upgrading my tune. The OS had actually been changed from the original 2001 GM OS to an earlier 99 OS then had a tune applied. I'm confident in the work that was done but have a question.

The IFR on my tune was set for the smaller injectors fitted to earlier LS1s.

I then upgraded to the custom OS3 and applied the HSV 04 Clubsport tune. Below is the different IFR tables, the before is obviously from the tune that was previously applied.

My question is how exactly will the previous table been possibly effecting the car?

before
kPa Injector Flow Rate (Grams/Second)
0 3.296875
5 3.351563
10 3.421875
15 3.601563
20 3.648438
25 3.703125
30 3.750000
35 3.773438
40 3.796875
45 3.828125
50 3.851563
55 3.882813
60 3.921875
65 3.953125
70 4.000000
75 4.046875
80 4.101563

after

kPa Injector Flow Rate (Grams/Second)
0 3.546875
5 3.601563
10 3.679688
15 3.875000
20 3.921875
25 3.984375
30 4.031250
35 4.054688
40 4.078125
45 4.117188
50 4.140625
55 4.187500
60 4.257813
65 4.328125
70 4.421875
75 4.523438
80 4.632813

[eboggs_jkvl]

The question is....

What size injectors are you running now? Set for those in your IFR and then start your tune.

Injector size:
99 ~26.4 lb
01 ~28.8 lb


Elmer

[dfe1]

If you're trying to correlate what is to what was to what should be-- IFR data that is lower than ACTUAL injector flow will cause AFR to be richer than it should be, if IFR is higher than actual, AFR will be leaner. The PCM calculates injector pulse width based on IFR relative to operating conditions (rpm, MAP, MAF or both and whatever other modifiers come into play). Obviously, you don't have to keep a 4.5-gram injector open as long as a 4-gram model to discharge the same amount of fuel-- and vice versa. Of course, if the VE table has been altered to compensate for the difference in injector flow, correcting IFR will require redoing the VE table.

[stigmundfreud]

elmer the car is a 2004 Monaro so should be 28.8

I beleive that when running with maf/o2's it should take care of things

I've currently got this tune applied, the VE table is using that from the HSV tune as currently have no widebands installed.

http://www.stigmundfreud.f2s.com/tuning/upgraded.tun