DI Engine tuning

In the process of tuning my F-type R 2016, a few mods top and bottom pulley, 100 cell cats, pods filters. PB 11.1 sec at 126 miles. My short trims are very positive at WOT past 6200 RPM...17%. Luckily the ECU (Med.17) remains in closed loop so ECU does a good job trying to hit my target lambda of 0.8. Boost is 13PSI. My question is given DI engines, use variable fuel pressures ranging from 500 psi at idle up to 2500 PSI at full load, is it possible and advisable to increase the fuel pressure at WOT to increase the amount of fuel delivered for that load, or increase the injector pulse width in that RPM, or adjust the (SOI) start of injection of fuel delivery earlier during the cycle to decrease the positive short trims.

Great questions. Generally a combination of those things.

Adding pressure within the limits of the system increases potential fuel delivery within a given injection window, plus better atomization always seems to help. You may have to adjust pressure limits, and also watch out and see how well pressure is controlled after you raise the target. Sometimes pressure control gets erratic when you stray from stock targets due to PID values not optimized at higher targets.

Earlier SOI often helps cylinder cooling at high loads, and broadens potential time for injection. Just be careful not to go too far as you can send fuel out the exhaust valves.

Thanks for you prompt reply mate, very much appreciate. Ill try increasing the fuel pressure and see is that helps reduce my positive fuel trims before playing with the correction factor in relation to injector pulse width per RPM. I guess if this doesn't help then it way be that the lift pump in the tank may be struggling to supply enough fuel to the DI pumps. However one would expect to see a check engine light if this was the case!

Ill shall command i higher value and see if the commanded value is achieved during the run.

Very interesting tuning these DI engines as fuel mixtures are leaner when compared to PI. Guess the fuel is so well atomized / homogenized, one can run a leaner mixture within reason.

If all pumps are stock generally the low side won't be an issue, but I don't know that engine platform so you may be onto something. If you stick a sensor or gauge on the low side and it's not dropping significantly under 3 bar, I'd leave it alone. Positive displacement pumps just need the volume delivered. They don't need super high pressure supply on the inlet side. There's a small benefit in slip reduction with higher low side delivery, but it's tiny when you're talking about say 3 bar supply vs. 5 bar supply.

Increasing fuel pressure target 5-10% would be a good test.

Then I don't know what your SOI values are at the moment, but with your significant airflow increase, there's a good change you need to move SOI back a bit (only at high airflow).