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I have done some basic testing on the 040 injector, but only at 300kpa and with gasoline. I also never recorded what "colour dot" this specific one had, but it should still be close enough for good control. Doc attached.
Attached Files
Bosch-0280158040.pdf
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Don't forget you can run softer timing and more air/fuel to bring mixture stability if need be.
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Picking this back up, I went back to the supplier and they have swapped the modified injectors they supplied for a set of flow matched with the following serial numbers. 0280 158 040 so any help with setting up would be amazing
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OK so, going back to my original question im guessing I am better lowering the fuel pressure to increase the PW. Either statically or dynamically
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The removal of the part number means they have been modified, usually by grinding the diffuser off. It will be a lottery if they can ever be made to work or not, they will have the atomisation of a garden hose and each injector will behave completely different to each other at short PW's.
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Appologies for tge delay but ive finally got the oart nunber from my engine builder. Apparently these are 1400cc not the 1000cc id originally quioted.
Attached Files
20250520_070517.jpg
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I'll get some pics of the injectors, next time I'm at the lockup
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What's the injector part number?
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Oh, don't forget to correct the fuelling under load, if required.
Early Calibras, using Bosch injectors, had, IIRC, 2.2 bar idle rising to 2.5 bar under load, with the regulator referenced to the smallish plenum under the single throttle body.
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Lots of factory 1980s/early 90s cars ran around 2.5 bar base, dropping down won't drop flow linearly however, it will basically respond as per orifice flow.
New flow= old flow × SQRT (new pressure/ old pressure).
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Thanks, as long as there's no physical issue to the injectors dropping to that pressure it ill give it a go. The fuel system is regulated 1:1.
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If you have the pressure regulator referencing engine/plenum pressure, it may drop it as you wish.
You "should" be fine dropping the pressure, but it may not make the difference you expect - worth a try.
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I've got a Link G4X, which has a short pulse width adder table but you get into a situation where if the fueling isn't what I want, is it the ve that's wrong or the spw table?
Ive checked a log and when idling on a warm engine I'm seeing pulse widths as low as 1.5.
The injectors aren't Injector Dynamics, they're just a more generic Bosch ev14 which only came with deadline information (which I'm not sure is overly accurate).
The long term plan is to run e85, but that's not going to be anytime soon so for now I'm only running petrol and seeing max duty cycle in the low 50% region so my thinking is I've got plenty of headroom to lower the bsse fuel pressure, increase the pw and get me into the linear operating range of the injectors.
I could also try something a bit clever and pwm the fuel pump to lower the pressure in the idle/cruise area and increase the pressure everywhere else in the map.
I just want to check running at a lower Base pressure isn't problem as I don't see many people running below 3 bar differential pressure.
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I find they work better at 3.5 bar rather than dropping below 3 bar, but I do use ECUs that allow me to enter data to offset the non linear behavior. You mentioned "modeled fueling", so if perhaps you're using Link, you can get that info from the ID website.
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As above, I've got 1000cc bosch injectors on a 4 cylinder 3sgte. Tuning idle on petrol is very hit and miss due to having very small pulse widths.
Is there any issues running a lower Base pressure to increase my pulse width into the linear operating range of the injectors? Currently i'm at 3 bar, so I'm thinking of dropping it to 2.5 or 2 bar.
I'm running modeled fueling so it should be a relatively simple tuning change and as a bit of a bonus it'll be less load on the fuel pump
