apalrd wrote:
We did the high mount NA tests in late 2012. I was not part of them.
Based on the tests in early 2013 which I was around for, with the same injector and low-mount location, we were running rather high duty cycles (as high as 80% at 12k rpm). The 'low end' is from 5k-9k or so, so DC is much lower. At the time we weren't syncing to half cycle so there would be two injections per whole cycle 360deg apart. We increased fuel pressure from 3 bar (43 psig) to 4 bar (58 psig) to reduce DC enough to guarantee full injector closing.
With the low mount we weren't able to measure power differences with any change of injection phasing, because the injector DC was always really high.
With the high mount injector, the plenum did cool notably, and the runner was cold to the touch. It was a weird feeling.
With the turbo, we lose delta P on the injector as we add boost, and need more fuel flow to begin with, so two injectors were needed. No numbers on injector duty, I know it wasn't high enough to trigger any errors.
Its probably worth the effort to about triple your injector flow rate and repeat the testing. Try to hold the redline DC to under 35%...I haven't tried it yest but I'm told by people I trust that it's a few % hp bump once you have it right. With only 2 cylinders and your own injector test bench there's no really need to mess with the fancy dynamically match injectors but Injector dynamics does have a 2000cc injector that is probably just what the Doctor ordered if 700
(I have the 1000cc version)
Also on a boosted application you really do want to ref fuel pressure to the manifold. If you are running at a fixed bar and over 1 bar boost your injectors are seeing under 3 bar putting them outside their rated range and probably not spraying very well. Maybe just replace the spring on your in-tank pump and bump it to 5 or 6 bar if you don't want to mess with anything external? Or maybe plug the internal regulator and and use the ECU to manage pressure?