Stock Injectors to Bosch 0 280 155 931
01-22-2014, 07:35 PM
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Stock Injectors to Bosch 0 280 155 931 I hope this helps anyone who has encountered the same confusion as I have with the Bosch 0 280 155 931 injectors. If anything looks inaccurate, please say so.
The injector flow rate programmed by GM into the stock 1998 Trans Am is exactly:
3.6172 g/sec @ 385kPa
Or approximately 28.7lb/hr @ 55.8 PSI
Which translates to about:
25lb/hr @ 3Bar
29lb/hr @ 4Bar
I replaced my stock injectors (Bosch 0 280 155 752) with 0 280 155 931. These are supposed to be an original replacement with a superseded part number, but are advertised in many places as 28.55lb/hr @ 3bar. That can’t be correct.
The results of a few flow bench tests I’ve come across online (conducted by independent parties who would have nothing to gain by skewing results) are closer representations of what the stock tune suggests they would be if the new injectors are truly “same-as-original parts.” (24-25lb/hr @ 300kPa.) I believe it’s safe to say that 0 280 155 931 are 24-25lbs/hr @ 3 Bar, and the injector flow rates in the stock tune do not need to be changed after replacing Bosch 0 280 155 752 / GM 12554271 with Bosch 0 280 155 931 / GM 12561462.
However, when I replaced my injectors, my car went from starting like a champion to… something I hoped nobody was around to hear. Assuming it was leaner on startup compared how it was with the older, leaky injectors, I messed with fuel prime quite a bit in an attempt to fix this, to no avail. Nothing changed. So I put fuel primes back to factory numbers. Then I changed the Ratio of Air to Fuel for Stoichiometry down to 14.22 to take into account the ethanol blend of fuel nowadays. My intent was to provide more accurate numbers for my PCM to use, but it also fixed the starting issue. I don’t know if this is a coincidence now that the weather down here in FL is like, freezing, and my car just starts better in cold weather, or what… but hopefully it will start fine when IAT temps are up, as well.
If you have access to tuning software, changing stoic AFR is worth a try if you’re having startup issues after an injector change. Just figured I’d mention it.
The injector flow rate programmed by GM into the stock 1998 Trans Am is exactly:
3.6172 g/sec @ 385kPa
Or approximately 28.7lb/hr @ 55.8 PSI
Which translates to about:
25lb/hr @ 3Bar
29lb/hr @ 4Bar
I replaced my stock injectors (Bosch 0 280 155 752) with 0 280 155 931. These are supposed to be an original replacement with a superseded part number, but are advertised in many places as 28.55lb/hr @ 3bar. That can’t be correct.
The results of a few flow bench tests I’ve come across online (conducted by independent parties who would have nothing to gain by skewing results) are closer representations of what the stock tune suggests they would be if the new injectors are truly “same-as-original parts.” (24-25lb/hr @ 300kPa.) I believe it’s safe to say that 0 280 155 931 are 24-25lbs/hr @ 3 Bar, and the injector flow rates in the stock tune do not need to be changed after replacing Bosch 0 280 155 752 / GM 12554271 with Bosch 0 280 155 931 / GM 12561462.
However, when I replaced my injectors, my car went from starting like a champion to… something I hoped nobody was around to hear. Assuming it was leaner on startup compared how it was with the older, leaky injectors, I messed with fuel prime quite a bit in an attempt to fix this, to no avail. Nothing changed. So I put fuel primes back to factory numbers. Then I changed the Ratio of Air to Fuel for Stoichiometry down to 14.22 to take into account the ethanol blend of fuel nowadays. My intent was to provide more accurate numbers for my PCM to use, but it also fixed the starting issue. I don’t know if this is a coincidence now that the weather down here in FL is like, freezing, and my car just starts better in cold weather, or what… but hopefully it will start fine when IAT temps are up, as well.
If you have access to tuning software, changing stoic AFR is worth a try if you’re having startup issues after an injector change. Just figured I’d mention it.
02-15-2014, 11:52 AM
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Cool. Thank you for sharing with us. Recently I bought an LS6 intake(p#12573572) for my project and it came with these injectors in it 12554271 (0 280 155 752). Now I know more about them. Thank you.
