LNF e47 injector limits
 

Wondering what the injector limits are on e47, stock motor, stock cams. Planning on running an efr on 24-26psi. Got away with it 434wtq on the stock turbo easily, obviously next year might be different.

Thanks.

Matt

Log your fuel rail pressure and Injector duty cycle. If the pressure tanks under ~1100 psi at the torque peak and Inj DC climbs over 40 % you are nearing the limit of the stock fuel system. You can ramp in the boost easier under 4k to help but your torque will suffer.

Also it depends on the amout of air your pulling through that will limit you!!! Exactly like (Iambroke) Said But the limitations are also the airflow

Increasing the diameter of the intake piping at the MAF sensor will lower the MAF freq the ECU sees if you overshoot the range of it. There is a MAF freq limit but I forget what it is. Perhaps James knows.

I think you will run out of fuel on the stock system before you run into MAF freq issues but it depends on the setup.

The hertz I think are 14000-15000..

Mine would lose pressure in the midrange as soon as boost peaked. I would throw low pressure codes. Term2 has ramped in the boost and torque but even then, I still spin 3rd. I can only imagine that the larger turbo may actually be ok in the midrange, but the higher airflow would make the pressure drop higher in the rpm range. But I'm thinking the higher rpm boost hit might actually allow the HPFP to build pressure. Still I think you are going to run out of fuel OP. I am hitting the max the fuel system will sustain on E47 on a stock turbo. If/when I turbo swap, more fuel will be needed.

Thanks for the input everyone.

Idk if this will help but im running a 5557 turbo on e47 and i was running 28lbs without running into fuel problems. Then again 2 totally different turbos

Yeah. The lag of the 5557 probably saved you. IDK how the hp fuel pump will respond to 26 psi of insta boost down low from an efr. If i get the byt efr 7064 it might be really hard for it to keep up with 55lbs of airflow.

yeah i want to get a efr but i cant find any...i hit full spool at around 3800

byt has one

Max injector pulse width depends on rpm, @ 6000 rpm there is an ignition even every 20ms for any given cylinder. Generally with PFI injectors after ~90% duty cycle the quantity injected goes non-linear, haven't seen any DI injector data, it might be able to handle a slightly higher % due to the rail pressure helping to close the armature.

With DI, we have a limited window. At the torque peak in the 3-4k range experience has shown me that >40% IDC is too high and inj window misfire will start happening. It's a different beast than port injection.

The fuel pressure drops and IDC climbs trying to compensate as we run out of fueling on the stock system.

So i assume that will throw misfire codes on all cylinders?

Gotcha, I was just confused when you said 40ms, 40% DC makes more sense.

Its too bad I haven't done anything with DI at my job, I'd love to learn about it.

Nope, it doesn't, just starts popping back in the intake.

Ya, I mistyped before. Fixt it. Sorry.