Mass Air Upgrade: Final Update pg2...

Reply #30 – July 24, 2008, 12:02:34 AM

So even if your car has gone above the adaptive capabilities of the ECU it doesn't "learn" the increase in fp and adjust for it? I didn't know that.

I know I'm really close to what the 19s can handle with stock pressure at full throttle. It hasen't thrown a lean code yet but a full throttle in 3rd gear you can feel it kinda getting close to "falling off" for lack of a better term. I would actually like to buy new injectors next year as my current ones have an unknow number of miles on them. I've thought about getting 24s as they should work fine with my current set up at stock fuel pressure, plus there might be an aluminium head swap in the works which leaves me with some breathing room.............

Mass Air Upgrade: Final Update pg2...

Reply #31 – July 24, 2008, 12:43:36 AM

Let's say with a certain combo you're running lean and @ 100% duty cycle @ say 4000 RPM to redlinewith stock pressure. You need to bump the pressure. Let's say you bump it to 60 and for a little while it actually runs rich (an ideal situation would be 54), The ECU will in a situation such as this learn and trim the duty cycle, but not to a point where it would throw a lean code again. It'll clean things up a bit.

At stock pressure you'd be beyond the limits because of physical impossibility. By increasing the pressure you've increased he theoretical and physical capabilities of the system --again if fed by enough fuel pump.

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I've thought about getting 24s as they should work fine with my current set up at stock fuel pressure, plus there might be an aluminium head swap in the works which leaves me with some breathing room.............

In that case go for it. If you were dead set done with your setup I would leave it be though.

Food for thought: On the Ford GT the engineers went with two (2) 34 pound injectors per cylinder instead of one (1) larger injector. The reason? It's easier to control pulse width on a smaller injector @ idle and part throttle than a larger one. At least that's what they say.