Here's what I've come up with based on the injector data. Let me know how it goes.
It's pretty close. You are better off going with good GM injectors, though.
Is your aeromotive regulator referenced to atmosphere or vacuum? This one is for atmosphere. Flatline flow rate vs kpa at 42 if vacuum referenced.
Last edited by SiriusC1024; 04-30-2023 at 05:03 PM.
i think my system is return less non referenced....there is no vacuum line going to the fuel rail or the regulator, and the only return line goes from the regulator back to the fuel tank, not the fuel rail back to tankOriginally Posted by SiriusC1024
Those are not 42 lb injectors.
252 g/min = 4.2 g/sec = 33.3 lb/hr @ 3 bar. Converted to 4 bar this would be the IFR for a returnless fuel rail:
38.45220604 38.69185185 38.93002247 39.16674483 39.40204501 39.63594834 39.86847942 40.09966212 40.32951961 40.55807444 40.78534851 41.0113631 41.23613893 41.45969614 41.68205435 41.90323263 42.12324958
Offset vs Volts vs VAC has to be made flat too if changing to referenced!
Data generated for an injector on one running engine might be OK for that engine. There are too many variables for the data to apply to any other engine with the same injectors. This is the 'well this is what my buddy used on his and it worked pretty good' method. I'm beginning to understand why the real experienced guys no longer bother getting involved in threads like this.
what does all this mean? my car is naturally aspirated so doesn't that make it 1 bar system?
4 BAR is 58 PSIG. 3 BAR is 43. Most advertised flow rates are given at an industry-standard 43 PSIG.
Injector flow rate is based on how much fuel pressure is in the rail - actually, the delta between rail pressure and manifold pressure (vacuum is still a pressure). More vacuum (lower pressure) in the manifold with a fixed rail pressure sucks more fuel through the injector. At WOT, or in a boosted app, higher pressure fights against the rail pressure and the injector flows less. This is why in a referenced system the flow rate/offset tables are all one value, and in a non-referenced/'returnless' they must be sloped, so that the computer can know how much the injector changes as the manifold pressure changes.
ok thanks for that explanation
i check that injector spread sheet and you are correct, i think what he is trying to do is trick the computer into thinking they are bigger than they actually are, then the computer sends the injector a shorter pulse width than it would if the injector was sized correctly
Last edited by JR92RS; 04-30-2023 at 02:48 PM.
Jesus H. I am done with this.
no need to get frustrated, how can i tell what mode my old turner has the car running in, i saw ltft disabled but i don't know what that means in relation to what mode it might be running in....maybe olstft but i don't know. can you look at it and tell me if it is a sd tune or maf only?
LTFT enable/disable has nothing to do with what mode it is running in.
WTF are you talking about. Even that tool is showing me 41.6lb then on up:
41.56995247 41.82902902 42.08651078 42.34242684 42.59680541 42.84967388 43.10105883 43.35098607 43.59948066 43.84656697 44.09226866 44.33660876 44.57960965 44.82129313 45.06168037 45.30079203 45.5386482
Ahhh I see. Those dicks over-rated advertised. It is a 33lb injector. Fixed in the tune. Thank you.
Last edited by SiriusC1024; 04-30-2023 at 05:10 PM.
That's ok you don't have to PM me. I have no problem being public.
1 - You have to put 4 bar rating into the tune. The injectors are rated at 3 bar, so it's scaled up to the 4 bar value.
2 - Min and default reduced by same proportion as min of original injector vs flow.
3 - Offset is directly from the table supplied by the manufacturer. It's the graph.
4 - Short pulse adder is zeroed after 1.38ms (datasheet) because the injector is behaving in a linear fashion. Short pulse adder is to account for flow while the injector is opening. See on the datasheet the flow for 2.5ms pulse. If you took 2.5ms of sustained it'd be roughly 10.5 (going off memory from last night). Here it's 7.56. It's smaller because when the injector is electrically told to be on there is a delay until mechanical on.
5 - If it starts up fine with the new injectors you can go ahead and leave it the way you had it. It's just something I tweaked based on your cam specs.
Last edited by SiriusC1024; 04-30-2023 at 05:04 PM.
He's extremely autistic about this kind of thing. It's like dealing with someone at macrumors forum. If you want to do something that's outside established parameters he starts a-rockin' and a-reeee-in'.
lol, i get that, but you didn't answer the question...is the car's ecm running an sd tune only, maf tune only, a blend of the 2 as gm intended, or something else....you looked at it the longest i suspect so i'm hoping you know and i can finally figure out what my last tuner did?
the problem i see with the way it was, was it is running very rich, stft's were constantly trying to pull 20-25%fuel.
does the cranking fuel tables effect idle after it is started?
No I didn't look because I don't want you to go changing a bunch of stuff at once. Looks like you're running MAF/MAP oem style. You wanting the MAF deleted? Also, are you running longtubes?
Not after runtime expires. Idle is its own thing.
i would'nt do that i'm too afraid of blowing my engine (in fact everything you changed has been implimented in stages as i researched each change)(i'm on the 5th reflash and havent gotten to the crank fueling yet), and that is how i want it too be running....oem style or a blend of maf and sd.
no i have short tube headers ....i thought about re-doing it but i dont want to lose any ground clearance.....i scrap on enough stuff
ok then i see no need for that update as it starts fine....unless i'm missing something
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