Would this combination work sufficiently well to pass MOT emissions?

block: stock Cinquecento FIRE 1.1
head: P75, complete with mpi inlet manifold and 866 cam
ecu: stock Cinquecento, for start

I will have to get a 3 bar fuel pump, sort out the P75 exhaust manifold and slice the spi injector wire to drive the 4 mpi injectors. I guess that if the P60 ecu can drive them so should the cinquecento one.

Then 2 more unknowns remain:

Can the cinquecento ecu adapt the fuel parameters adequately based on the λ feedback? ( could 'help' it with playing with the fuel rail pressure ;-)

Will the cinquecento ignition maps be good enough? (I guess they will, otherwise the P75 cam to cinquecento mod would not work).

Just to clarify, I KNOW, this is VERY sub-optimal. I plan to either get a piggy-back ecu (DET3 seems promising) or an eeprom programmer for fine tuning at a later stage, but the cinquecento is my daily driver to work and I cannot afford it being off the road. I just need it to be no worse than the stock cinquecento engine.

PS: I do have the P75 ecu, but I see no benefit on trying to use that over the cinquecento one. Both will have the wrong parameters for the 'hybrid' engine.

Check the fuel pressures required. I'm not 100% that the P75 used 3 bar (although the later MPI cars did).

Emissions wise, you're just swapping from one batch system to another, so it may well be fine (no guarantees, though).

should work fine.

blu73 said:

should work fine.

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It would need the P75 ecu to power 4 injectors and alter the duration, the P75 ecu I designed to run with the 866 cam and the extra fuel pressure & bigger throttle body and higher compression, p.s the P75 runs 2.5 bar fuel pressure as standard also you can just plug this ecu in once you've spliced the 4 injector wiring in place

It may run a bit better with a P75 ecu granted but it will work fine with the 1108 ecu or even 1242 spi ecu - it would not be the first cento to run a 75 engine with a spi ecu.

Using the 75 ecu is the better way to do it but if you splice the injector wires 4 ways and plug it into a spi ecu then it will work, the 75 batch fires so injectors will fire just the same as with a 75 ecu, it just not be as perfectly suited as the 75 ecu.

A tiny detail - the SPI ECU fires injectors twice as often as the MPI ECU (and in smaller dosages obviously).

I might have a P75 ecu, codebox, key and engine loom (I think, some routing about parts would need to be done to be 100%).... PM me if you are interested yiorgos, but it would be prudent to just get the ecu and key from the donor car really, offers there though.

blu73 said:

I might have a P75 ecu, codebox, key and engine loom (I think, some routing about parts would need to be done to be 100%).... PM me if you are interested yiorgos, but it would be prudent to just get the ecu and key from the donor car really, offers there though.

Click to expand...

Unfortunately, the donor car has been converted into pans and pots long ago, so it's codebox and keys. I was young and naive, did not know the tricks and the scrapie man not on the ball either :bang:

I do have the P75 ecu & loom though, but 'locked', presumably.

The engine will neither be C54 nor P75, so neither ecu will be 'right', but at least the P75 will drive the injectors properly.

As it seems, my engine is deteriorating fast (thirsty, water ) and a rebuild will be required very soon. I may pm you the next few weeks ....

Thanx

Y