Lower my fuel pressure to help w/fuel injectors.., ...being too large??? Options

[Mueller]

Running 2.0 injectors on my stock 1.8, new fuel injection fires all 4 at one time (batch), I have a feeling new injectors are too much....anyone lower their fuel pressure to compensate for large injectors??

I'm wondering how low can I go yet still retain a nice reliable pattern?????

[airsix]

QUOTE (lapuwali @ Jun 13 2005, 10:32 AM)

Perhaps none of this makes any practical difference (who knows how bad carbs are in flow variation?), but there's certainly going to be some lower limit. I'd expect 1.75ms to be very close if not over that limit. Dave Hunt noticed that, when running 2.0 injectors on a 2.0 with MS, that only 0.1ms in pulsewidth made a noticable difference to idle quality.

Since there were so few production automobiles using solenoid injectors in the early '70s I'm convinced that Porsche/VW/Bosch "made due" with what was on the shelf - grossly oversized injectors. By today's standards our injectors are HUGE for our per-cyl displacement. Take for example the Subaru 1.8L-Turbo injectors I was using - they flow about 25% LESS than the D-jet 1.7 injectors. Lucky for us, our D-jet injectors are very low impedence and the coils charge quickly, so you can tune your PEFI to use super-short pulse-widths just like the factory did with D-jet. If the PEFI doesn't have the sufficient resolution to work with such short pulse-widths then the only logical alternative IMHO is smaller injectors. I think Mike's dillema is that he's adding forced induction, so he will probably need to keep the large injectors. It's almost a cake-and-eat-it situation. Hopefully his Link system will be able to work with the very-short pulse-widths at idle. I'm guessing it will since the Link is very popular with the WRX tuners.

-Ben M.