ok i have a seicento sporting mpi 53 plate, and been thinking about building a complete engine up for it, i have done this with other cars but not 100% on the fiat FIRE engines

so far i have come up with

1242 8v bottom end
*16v pistons and rods from a punto
My current Head mpi 1.1
75 Cam shaft
standard headgasket

wanted to go turbo but parts are far too hard to sauce, evern more so for the mpi, so im hoping this set up will be similar to a low boost 1.1 set up

Compression will be too low with the 16v piston running it n/a

Way, way, too low on compression. The only benifit from running the 16v pistons and rods in an 8v is a lower CR, and even then, some have calculated that it's a wee bit too low for charging. It'll be something under 8:1.

ahh i was under the inpression the CR ould be withing a relitivly normal figure, im assuming sticking with the standard 8v pistons and rods would be ideal then,

Yes. I'd look at junking the manicat in favour of a an SPI one, popping on a Supersprint manifold, decent induction (GSRs are out of production for MPI cars, as far as I know, so the Focus ones are probably your best cheap bet) and a remap.

fingers99 said:

Way, way, too low on compression. The only benifit from running the 16v pistons and rods in an 8v is a lower CR, and even then, some have calculated that it's a wee bit too low for charging. It'll be something under 8:1.

Click to expand...

7.8:1 from what i have read..

IIRC the MPi head has smaller valves in the interests of economy.

Cheers

D

P75 head or some late P60 heads have larger valves.

The bit about parts being difficult to source has some truth, but the reality is that there's little of much utility out there for SPI engines, too.

Fundamentally, all you have to do is fabricate -- or, at least, alter -- the inlet and find (or modify) a suitable exhaust (or fabricate one). Get a decent welder on board and you're half way there. Then put together a (please God, not MF2 based) ECU/System.

Turboing any engine not designed (or, at least, developed) for it will always pose problems, but, then, getting similar outputs from an N/A engine will pose more.