Map63Vette
Well-Known Member
I've been working on refining my tune now that I'm driving my car regularly again and I'm getting to the point of digging into all the little settings that I didn't really pay that much attention to before to try to get it to feel as OEM as possible despite being an entirely different computer system. I've been fighting an issue where my highway cruising AFR is different going to work in the morning compared to coming home. I asked about it on the Megasquirt forums and have been looking into all the different places I can change it, and I think the first place I want to start adjusting is at the injector settings themselves based on some feedback I got there. I know I can change the temperature calibration table to get there, but that curve should theoretically follow the ideal gas law, so I'd like to try to find the real root issue and not just fix the symptoms.
So that being said, they suggested I look at my injector dead times, which I think makes sense. I never tuned or adjusted those as I never had any info to adjust them with. So with that being said, does anyone have any info on the earlier 5.7 model injectors (pre-09)? My understanding is the very early engines (03, maybe 04) ran at 43 psi while the later engines upped that to ~60, so injectors might have changed. My setup should be stock 5.7 injectors from a 2006 car engine (assuming that makes any difference), which I believe are Mopar P/N 4591851AB according to their manuals at least. I'll try to check the actual numbers on my injectors to be sure, but I have little reason to believe they would have been changed before I got the engine. However, being stock injectors, finding information on their actual specs seems to be more difficult than aftermarket ones. I think these are something like 24 lb/hr if I remember correctly (also used on the 4.7 engines), but I've seen various values in my searches over the years. Size is easy enough to work around in TunerStudio, but I'd really like to try to find some dead time info if anyone has any. Does something like HP Tuners have a table that could be pulled from a stock ECU? I've managed to find some stock VE and ignition tables over the years that I've used to compare my tune against, but my Google-fu is failing me on injector specs, so hoping someone out there might have an older stock computer they could look at.
So that being said, they suggested I look at my injector dead times, which I think makes sense. I never tuned or adjusted those as I never had any info to adjust them with. So with that being said, does anyone have any info on the earlier 5.7 model injectors (pre-09)? My understanding is the very early engines (03, maybe 04) ran at 43 psi while the later engines upped that to ~60, so injectors might have changed. My setup should be stock 5.7 injectors from a 2006 car engine (assuming that makes any difference), which I believe are Mopar P/N 4591851AB according to their manuals at least. I'll try to check the actual numbers on my injectors to be sure, but I have little reason to believe they would have been changed before I got the engine. However, being stock injectors, finding information on their actual specs seems to be more difficult than aftermarket ones. I think these are something like 24 lb/hr if I remember correctly (also used on the 4.7 engines), but I've seen various values in my searches over the years. Size is easy enough to work around in TunerStudio, but I'd really like to try to find some dead time info if anyone has any. Does something like HP Tuners have a table that could be pulled from a stock ECU? I've managed to find some stock VE and ignition tables over the years that I've used to compare my tune against, but my Google-fu is failing me on injector specs, so hoping someone out there might have an older stock computer they could look at.
