Muzzie,
The fuel injection in the Uno Turbo Mk1 operates in what is called 'open loop' mode. This means there is no feedback from the oxygen sensor (there isn't one!) so the ECU does not 'know' when to enrich/lean out the fuelling. Instead, it operates off 'maps' that correspond the engine load/speed with a predetermined injector duration (opening time) for a known constant fuel pressure.
Even on newer systems, the ECU rarely relies on the oxygen sensor all the time - usually only during light throttle/cruise conditions.
What I'm saying is that you shouldn't fit bigger injectors without fitting something to re-map the ECU (or of course, fitting an aftermarket ECU e.g. Megasquirt). Jaycar (where I used to work) sells a kit called The Fuel Adjuster. It intercepts the signal from the airflow meter, allowing you to dial the voltage up or down in fine increments for different engine load 'setpoints'. This allows you to basically turn down your bigger injectors over most of the engine load range, yet still have them there for the high loads.
The kit is not cheap (for a kit) at about $100, plus another $60 for the LCD hand controller used to program it (also useful for other kits like the electronic boost controller). But in aftermarket engine management terms, that's cheap! (I'm sure Steve will agree; he knows a lot more than I do about these things...)
You can also now appreciate the two other options available to you - have a fifth injector, triggered when necessary at high engine loads, usually by a small circuit.
Or, the other way to increase fuelling while keeping everything else standard. Increase the fuel pressure! There is probably a clever way to do this related to the increased boost pressure. I'm not sure about this one, but it would seem to me to be the cheapest option, provided you could ensure that fuel pressure was standard for all but high loads.
oh no, my Enter key has just stuck down, so who knows what happens next. Damn, this Microsoft Natural Keyboard is only 12 years old this year!
Cheers,
-Alex
The fuel injection in the Uno Turbo Mk1 operates in what is called 'open loop' mode. This means there is no feedback from the oxygen sensor (there isn't one!) so the ECU does not 'know' when to enrich/lean out the fuelling. Instead, it operates off 'maps' that correspond the engine load/speed with a predetermined injector duration (opening time) for a known constant fuel pressure.
Even on newer systems, the ECU rarely relies on the oxygen sensor all the time - usually only during light throttle/cruise conditions.
What I'm saying is that you shouldn't fit bigger injectors without fitting something to re-map the ECU (or of course, fitting an aftermarket ECU e.g. Megasquirt). Jaycar (where I used to work) sells a kit called The Fuel Adjuster. It intercepts the signal from the airflow meter, allowing you to dial the voltage up or down in fine increments for different engine load 'setpoints'. This allows you to basically turn down your bigger injectors over most of the engine load range, yet still have them there for the high loads.
The kit is not cheap (for a kit) at about $100, plus another $60 for the LCD hand controller used to program it (also useful for other kits like the electronic boost controller). But in aftermarket engine management terms, that's cheap! (I'm sure Steve will agree; he knows a lot more than I do about these things...)
You can also now appreciate the two other options available to you - have a fifth injector, triggered when necessary at high engine loads, usually by a small circuit.
Or, the other way to increase fuelling while keeping everything else standard. Increase the fuel pressure! There is probably a clever way to do this related to the increased boost pressure. I'm not sure about this one, but it would seem to me to be the cheapest option, provided you could ensure that fuel pressure was standard for all but high loads.
oh no, my Enter key has just stuck down, so who knows what happens next. Damn, this Microsoft Natural Keyboard is only 12 years old this year!
Cheers,
-Alex
