Running lower Base fuel pressure to get out of the non linear area of my injectors

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

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.

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.

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.

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.

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).

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.

What's the injector part number?

I'll get some pics of the injectors, next time I'm at the lockup