1.7 big bore fuel injection Options

[Damo]

Hi all. I’m in the process of converting my stock 1.7 to a big bore 1.9 and was looking to keep the stock fuel injection system if I can. I would just like to know if this is possible and how the original FI is tweaked, do I need to fit bigger injectors and mess with the throttle position etc etc. I’ve been told it’s possible but would like more detail so that I can continue. There must be quite a few out there that have done the big bore so hopefully someone will jump in. Thanks.

[brant]

Damo,

I don't know the answer exactly for a 1.7

when folks put the 96mm bore pistons into a 2.0, they use the stock injectors but change the mixture through tuning of the MPS

to appropriately tune it... you need either the old, rare, and expensive device bosche used... wavetech, I think... but then the settings for that device would be appropriate to stock and stock means 1970 fuel additives and fuel that was sold then

today the fuel has changed. So I would argue that you need the 2nd method to tune to todays fuel. That would be a wide band o2 sensor to essentially read the fuel mixture under load, while driving the car and adjust the MPS settings to bring the AF ratio into spec for todays fuels.

I can't weigh in with any experience on if you should use the stock yellow 1.7 injectors or switch over to the 2.0 ones...

the 2.0 MPS also has an extension ring inside of it that allows the diaphragm slightly more range of movement to meet the 2.0 needs...

I'm not sure if you will need to fully open the 1.7mps and add that spacer or not?

hopefully this bump will bring you that answer about the MPS and about which injectors to use

brant