As I already have an 1242 MPI head, fitted on my 1108 engine block, it's time to change the SPI manifold for the MPI one.

New fuel pump and rail of 4 injectors will be fitted as well as Punto 75 throttle body. This is one of the first mods done to racing centos here in Greece and i know it pushes 10-12 more HP right away (it gives 15 HP more at the 1242 engine, isn't it?)

My concern is if the standard ECU can work with this arrange, or Punto 75 ECU is needed. Electrical connections are the same between the two, even the injector wires are the same with the 4 new, only they are connected in parallel. And as they are 14 Ohms each, ECU sees the same impedance as with the single 3 Ohms one.

What I am trying to say, is that probably the 1108 ECU could be adapted to work with a MPI setup, if injection and ignition map is transfered from the 75 eprom to the 55 one. This would eliminate the need for a new ECU when a 1242 MPI engine (or the 1242 head) is fitted to a cento, only a new chip inserted to the original ECU.

1242 SPI owners could also benefit from this upgrade, if camshaft/injector rail from 75 is fitted, along with this chip installed.

If anyone has a source for more details on 1108 and 1242 maps, please inform me. If the project succeeds, i can supply these chips really cheap, less than 25 pounds or so.

As far as i knew, the ECU on the MPI setups was different - and would have to be swapped over, so you'd need the punto75 wiring loom. I am not sure on this though as i've never looked closely into it.

I do know though you will need a higher pressure fuel pump as the SPI one runs around 1bar, where as the punto75 varies from 2.5 to 3.5bar.

When you say camshaft/injector rail - do you mean use the punto75 head with inlet manifold on an SPI setup? Thats not a good idea, as the punto75 inlet manifold isn't to meant to have fuel entering it and it'll pool.

It certainly needs a 3bar fuel pump, it's in the list. Wiring loom is not needed to change, we already checked it, we already have a 1242 MPI Cinq, running on standard loom and Punto75 ECU.

What i am talking about, is fitting a 1242 MPI head (or a whole engine) to an 1108/1242 SPI cento and a modified chip with the maps from the punto 75.

Even those of you with a 1242 SPI, could fit the MPI cam plus this modded chip and gain 9-10 HP for a very low price...

i see.

there are a few people on here running the cam from the punto75 in their 1242 SPI setups - but as of yet, i know of no chips that have been done to take this into account.

That's what i'm talking about. The info exists. We don't have to look further, it's inside the punto 75 eprom. I have the bin file of this eprom. I need help to locate the hex adressed where the injection and ignition maps are and copy them to the 55 chip.

It won't give the +15HP that the 1242 MPI has over the 1242 SPI, but a +10 is quite sure (larger ports and bigger TB can give the rest 5...)

Asteris said:

That's what i'm talking about. The info exists. We don't have to look further, it's inside the punto 75 eprom. I have the bin file of this eprom. I need help to locate the hex adressed where the injection and ignition maps are and copy them to the 55 chip.

It won't give the +15HP that the 1242 MPI has over the 1242 SPI, but a +10 is quite sure (larger ports and bigger TB can give the rest 5...)

Click to expand...

The data structures may be very different, so it might not be that obvious

Try PM'ing 'mcritch' on here. He developed a chip for the cento so could possibly shed some light on the structure of the Cinq map chip (or he can find it out).

If / when you do (its bound to happen) find out please please please!! (I really cant stress it enough) tell me , as this is a really exciting project in my eyes (it solves my ECU problems very very well )

Hmm...Ive finally made some useful use of my sparetime at uni'.

Sticking a 21ohm (20ohm may suffice, I dunno yet) resistor in parallel with the injectors brings the overall resistance of the network to 3 ohms. Which means the ECU won't get too frightened.

Hmm...20ohm gives overall resistance of 2.98ohm, which would probs be OK, if 21ohm is unavailable (but its probably one of the preferred values anyway)

Il problema non è la resistenza ma la corrente...