Ok in a couple weeks I will be helping a friend install a charger on his pre 2000 2.4 auto. He has the full GM kit. My main question is with the injectors. I know and understand the injector constant. I also know on the GM reflash the injector constant it higher, and not lower. My question is since we will not be using the GM reflash on his car I will want to set the injector constant lower ? and not higher correct? Also I know the GM injectors are 310cc, but what pound are they? Thanks for any info.
FU Tuning
I'm not sure where it is but if you search I think Shifted has posted a formula for calculating the correct injector constant. This should at least be able to get you running, from there you will need to look and see how the car is idling when it is in closed loop. If it is having a hard time staying near 14.7afr once its warmed up then you need to tweak the injector constant. Then from there you can begin VE tuning for boost.
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BlackEco wrote:I'm not sure where it is but if you search I think Shifted has posted a formula for calculating the correct injector constant. This should at least be able to get you running, from there you will need to look and see how the car is idling when it is in closed loop. If it is having a hard time staying near 14.7afr once its warmed up then you need to tweak the injector constant. Then from there you can begin VE tuning for boost.
Thanks I know the formula for figuring injector constant. I was asking if I should try and be like GM with the higher constant (when normally you want a lower one with bigger injectors) or not.
FU Tuning
in playing with the injector constant to get mine tuned, i noticed the lower the constant the higher the injector pulsewidth. mine went from .26 i think stock all the way to 46.something before the car started without intervention. not sure of the true afr because my sensor even has warmup time on a hot start but i was happy with the idle afr at .467
"...and then God said let the 2.2's have potential. Thats when hell broke loose..."
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Might want to take a look at putting the 97 flash on there, its speed density instead of alpha-n.
Considering that. We actually have 2 97 ECU's that we are waiting to test to see if one might be a speed density ECU. If it was we were going to put it on this car and run it.
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It also doesn't have an IPW vs. VAC chart rendering it useless for adding much fuel with boost.
And no, even after numerous requests, HPT won't help us. They insist the chart doesn't exist.
Best bet is my FMU method with a 98-99 PCM where you can add and subtract fuel with boost via IPW vs. VAC with a faked 2 bar setup.
As for answering your question - lower #. I've run Stock, Brown tops, 440cc, 550cc 750cc and 1000cc injectors on a 99 PCM (low impedence)
This is also interesting info on the speed density ECU's. So seems staying with the factory ECU in the 99 is best bet. We are not planning on running a FMU. I know another guy with a 99 and GM charged with a fake 2 bar map, no FMU has a really nice tune and drive well. I feel on a charged car the fake 2 bar will work really well because as RPM's increase the boost will. On a Turbo car you can chaqnge boost at different RPMS more.
As for the injector constant I was sure lowering it was correct, but just asking because I knew GM did it different with the reflash.
Thanks for the info.
FU Tuning
higgins..i have my S/C flash on my laptop if you have any questions you can contact me.
. wrote:higgins..i have my S/C flash on my laptop if you have any questions you can contact me.
Thanks I have a couple as well.
We got the charger on and the car running. My only real question is why bother using the 2 bar map sensor? I have read soo many times where people say you need the 2 bar map. We ran the 2 bar map, but it would only read up to 73KPA. Using the stock 1 bar it will read up to 105KPA (ECU I'm referring to). I realize it is actually seeing more than this because of boost, but the ECU is only seeing what it knows to read. Using the 2bar map made timing control sooo much harder than with the stock map.
FU Tuning
