Bigger Injectors=KR?

[Lumpo]

I just installed 42.5# Injectors in my car because my stock 36# injectors were maxing at 108% but i had 0 KR. So i took 42.5/36 and got 1.18 so i multilied my IFR table by 1.18 to get them scaled correctly. I then went for a ride and my LTFT were really negative about -14ish at cruise and my INJ Duty was still about 95% at max RPM but i had 0 KR. I then tried adding 3 to my entire IFR table and it really brought my LTFT down to -5 to +5 so not perfect but much closer and it also lowered my INJ Duty 20% so im now at around 80% INJ Duty. The only problem is now i have up to 3* KR at top of second gear. What am i doing wrong? Whats the correct way to fix my problem?

Scan...

http://www.scandepot.net/viewscan.php?pk=5261

[murphinator]

you applied linear math assuming all injector characteristics other than size would be identical - they are not

first off you are going to need to make changes to data that you cannot access with public hpt - you will have to ask someone with beta if additional injector data has been added beyond injector flow rate. or you will need to use tiny tuner to change the things you dont have access to in HPT.

you will need to know what pressure your 42's were rated at as well as their full characterization things like short pulse adders , voltage offsets ,etc..

read through this thread and you will better understand wtf I am referring too...

http://www.hptuners.com/forum/showth...t=pulse+adders

[BlackGS]

Looks like you just need a PE tune. Your O2's are in the 800's, and you are probably running a little lean up top.

[Lumpo]

The numbers should be bigger than stock if im going bigger injectors correct in the IFR table?

Info on stock Injectors...
12.2 Ohm, 354cc @ 3 Bar (33.71 lbs/hr @ 3 Bar)
34.28 lbs/hr @ 45 psi

Info on 42.5 Injectors...
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
Coil Resistance: 15.9 Ohms / High Impedance / High-Z

[umrjmac]

Looks like you just need a PE tune. Your O2's are in the 800's, and you are probably running a little lean up top.

You can cover up bad fuel injector data by playing with the air model, but it has some side effects. The best answer, as noted above, is to get the proper injector data. If the data is good, then changing out injectors shouldnt have a significant impact on fuel delivery (other than possible min pulse width overfueling shenanigans at idle because the new injector delivers more fuel and cant open/close fast enough to deliver a small enough value to keep you at stoich instead of rich)

[passingpower]

Looks like you bought a set of Racetronix that cross to the LUCAS 009s.
Rumor has it that no one has the short pulse and offset model for these 'cause the wide variances in the manufacturing process makes it impossible to model them!

There's no such thing as 'scaled correctly' when it comes to fuel injectors. Dump the linear math. Read HPT help for the correct adjustment method then search this forum for "Bernoulli" to find out why.

[3800 cavalier]

you applied linear math assuming all injector characteristics other than size would be identical - they are not

first off you are going to need to make changes to data that you cannot access with public hpt - you will have to ask someone with beta if additional injector data has been added beyond injector flow rate. or you will need to use tiny tuner to change the things you dont have access to in HPT.

you will need to know what pressure your 42's were rated at as well as their full characterization things like short pulse adders , voltage offsets ,etc..

read through this thread and you will better understand wtf I am referring too...

http://www.hptuners.com/forum/showth...t=pulse+adders

yes every injector is different and all the proper tables need to be inputed properly. beta lets 3800 users access some important tables. v8 guys have many more to access but at least its something that helps lots.