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I keep running into this EV1, EV2, EV6, etc designation for fuel injectors. Are these EV types an industry standard? I did read somewhere that the EV number describes a body style. Does that imply that all EV1 injectors are interchangeable from a mechanical perspective? And does the EV number define the connector used?

I know this probably isn't difficult .... but I'm still missing something.

Al

EV1 and EV6, both long, are compatible. My Volvo came with EV1 style (fat) injectors, and now I have the skinny EV6 type with no other changes.

I have another question .... and I'm not sure if there will be an easy answer.

I've been looking for a replacement injector for my Bosch 280 150 803 injector with a higher impedance than the 4.6 ohms. I started out looking for something with a similar flow rate, then I realized the Bosch injector is rated at 2.5 BAR but the system I have is running at almost 4 BAR. I have no idea why it's done this way, my understanding is it will have a poor spray pattern like this.

But that's not my main problem, the problem is how do I judge the flow rate, will the flow rate increase linearly with the increased pressure? If it doesn't, then I can't do this the easy way, I'll have to go back to square one and calculate the flow requirements, then get a regulator that matches the pressure spec for that injector.

Al

Higher pressure is fine. If anything it improves the spray pattern (higher pressure -> finer mist due to more turbulence).

Flow is proportional to the square root of pressure. Doubling pressure increases flow by a factor of 1.41 ( aka sqrt(2)). Quadrupling pressure doubles flow.

I think bosch rates everything for 3-5 bar for street applications and 3-8 race? something like that. 4 bar is pretty common and what I run but a failing fule pump did allow me the "opportunity" to test down to under 1 bar and that seems to be about when the flow math stops working right as that is where I notice something wrong with my ecu no longer correcting quite right.

O/K ... thanks guys, I'll keep plugging away at this until I get the big picture.

mk e, you mentioned you ran the pressure down to 1 bar before the flow calculations started to fetch up in the ECU. Does that imply your ECU is using fuel pressure as one of it's inputs?

Al

ayard wrote: ↑

Wed Aug 18, 2021 11:42 pm

mk e, you mentioned you ran the pressure down to 1 bar before the flow calculations started to fetch up in the ECU. Does that imply your ECU is using fuel pressure as one of it's inputs?

Al

Yes Fuel pres , fuel temp are inputs. I run GM style injector tables using 3 tables with flow v pres, flow v pres&voltage, and short pulse time correction and I adjust the fuel viscosity for temp as a 4th correction.....injector dynamics who supplied my injectors published the data so I used it. This only seems to matter when things are going wrong, I've used simple non-corrected setups many times with no real issues but here I had the opportunity to platy with something fancier so I took it.

ayard wrote: ↑

Wed Aug 18, 2021 11:42 pm

mk e, you mentioned you ran the pressure down to 1 bar before the flow calculations started to fetch up in the ECU. Does that imply your ECU is using fuel pressure as one of it's inputs?

Mind you, he's not using rusEFI. rusEFI does support a fuel pressure input for automatic flow compensation, though. It works really well - you can pull the fuel pump fuse, and the engine keeps running totally normally until the fuel pressure literally hits zero.

You can of course manually calculate the correct flow rate at your pressure. For example, my injectors are rated at 440cc/min at 3 bar, but I'm running at 2.5 bar. Pressure ratio is 0.833, so the flow ratio is 0.913, so I enter 402cc/min to rusEFI.

PS: this is exactly the same math rusEFI does internally if you have a fuel pressure sensor configured.

mck1117 wrote: ↑

Thu Aug 19, 2021 12:59 am

Mind you, he's not using rusEFI.
....
PS: this is exactly the same math rusEFI does internally if you have a fuel pressure sensor configured.

Yes, sorry for not making that clear but I thought I'd read before that you support a fuel pres sensor and that with the flow math you describe has got to get you most of the way to way since flow changes are most of the error when fuel pres changes. I added the extra bits to my setup because of my OCD mostly...which is why the stupid thing isn't finished