Daft question, I suppose, but I was just wondering if the standard MY98 ECU could control 550cc injectors and, if not, what would the result be?

 

At a guess, the car would run, but it would be too rich off boost, you'd get crap fuel economy and most probably borewash over a longish period.

380 to 550 is a hell of a jump (almost 50% more)

Rich

 

Without correct engine management programming of the injectors, you will simply not get these injectors to operate correctly.
Simply fitting overbored injectors will not increase engine performance as it will no doubts overfuel the engine creating more problems than enough, like said previously - even causing engine /piston failure due to such.
I would think again prior to fitting, get the car to someone who knows what they are doing before it costs you an engine rebuild.

 

As I thought I didn't intend doing this but I have a set of 550s on the way which I intend to fit with another ECU and I was just curious. Thanks.

 

Ideally standard MY98 ECU could control 550's well enough to get through MoT with just a centre CAT ;-)

Would this work with 440's given the smaller jump in injector size ?

 

I would have thought once the lambda is up to temp you could drive it closed loop OK.