1986 Porsche 944 turbo injector question

Talk and Tech about turbocharged 924/944/968 cars
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Fender8024
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Hi everyone I was wondering if I could get help I have a 1986 porsche 944 turbo stock with a Venturi delete. One of my injectors started leaking and I have a friend who is selling me some rebuilt bosch 0280 150 785 injectors for cheap would these work on our cars?

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Belgian951
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I heard that if the flow is the same as the originals, you're good.
1986 944 Turbo Garnet Rot Metallic

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four0four
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Belgian951 wrote: Mon Oct 30, 2023 12:23 pm I heard that if the flow is the same as the originals, you're good.
Not quite. If the flow is matched and the impedance is the same, and even then you've got the opening characteristics to worry about (idk how much of a practical issue this is. my intuition says moreso with high-z injectors). Those are high-z,the 944 ones are low (ish) Z peak-and-hold, using some custom Bosch driver ASIC.

I'm not sure if the p&h drive circuit would be happy with those. If I recall correctly it can be, but with changes to the DME program (so either a chip or some patience in a disassembler ;))

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Tom
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Fender8024 wrote: Mon Oct 30, 2023 11:42 am Hi everyone I was wondering if I could get help I have a 1986 porsche 944 turbo stock with a Venturi delete. One of my injectors started leaking and I have a friend who is selling me some rebuilt bosch 0280 150 785 injectors for cheap would these work on our cars?
Those are not a good match for the stock 951 injector. Stock injectors flow 384cc/min at 3 Bar and have 4.6ohms resistance/impedance. Google searching say the 028015085 are listed as 310cc/min at 3.93 Bar, so considerably less flow, and 14.5ohms of resistance/impedance.

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Tom
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Belgian951 wrote: Mon Oct 30, 2023 12:23 pm I heard that if the flow is the same as the originals, you're good.
Need to be very careful with the resistance/impedance on the injectors. 951 injectors have an unusual impedance rated at 4.6ohms. If you use a traditional low-impedance injector in its place (with half the resistance) they will draw more current than the DME's injector driver is designed to deliver and eventually (or quickly) burn out that circuit in the DME. In the old days, people would add a high-watt 1 or 2 ohm resistor inline with low impedance injectors to keep the DME alive. Just FYI in case you are ever tempted to change injectors. :)

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Belgian951
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I just hope I don't have to change injectors anytime soon because those OEM injectors are like 400 each. Yikes!
1986 944 Turbo Garnet Rot Metallic

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notny41
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I don't know if you want to try to clean your injectors - or if this would even help with a leaky one, but I used this setup with good success on my injectors (I just used a 9v battery and a momentary switch - that used to be a seat heater button on a volvo) :
injector cleaner.jpg
injector cleaner.jpg (633.11 KiB) Viewed 794 times


Here's a demo by the guy I learned it from:

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