what pistons for a stroked 1420cc T2 turbo set-up?
Turbo Mini Forums

dear forced inducuction junkies,

I now have a fairly large pile of quite good bits and want to bolt together something fairly useable - list as follows:

Non S 1275 block overbored to 73.5mm (i think)
stroked crank with omega pistons
stage 3 big valve head 12G940
brand new T2 turbo
brand new 1 3/4 su carb

my main need of help is what compression ratio should I be looking at to run the T2, or better still is there a set of pistons better suited to the project.

any help or advice gratefully received.

regards

Roofless

rover mini cabriolet 1380 and zeemax kit running 14" wheels.

you hit the nail on the head - torque is what I'm aiming for.
Like I said all these bits are lying around, i might as well make some use of them. Cam suggestion gratefully received - the T2 is brand new so should spin up well, and looking at Renault 5 turbos in standard form they seemed to give a nice push at moderate revs. things like boost etc is going to be a voyage of discovery but may be fun.
The next key question is whether to use bike throttle bodies / injection or stick with the Hif44 ( also brand new)

thanks

Martin (roofless)

Roofless,

I have thought about going down this route also, the main problem is will you be able to get your CR low enough??

with 24cc chambers in the head and the same bore/stroke you are looking at, you get 8.8:1 CR with 18cc pistons. I used 24 becase thats what my head is.

Peter, what's the quality like on those Ross's? the price seems to good to be true!

also you'll be best with the SU, bike stuff/ injection will be to much hassle/expense to get working on the quirky 5 port head. But by all means go for an ecu to control the sparks, this will make a big difference!

Edited by Joe C on 4th Oct, 2006.

I'll be amazed if you can get a 1420cc block to hang together with a turbo! That's lot of iron that's been chopped away that would've come in handy when coping with turbo temperatures, pressures etc.

should be fine,

people are already running 73.5mm bores with no probs, the only difference is the meatal removed from the crank to enable the longer stroke, but as a NA bottom end reving to 7500 will be more stressed than a turbo one reving to 6500 that should cause no issues.

The only issue will be strength of the pistons, due to mods to get the longer stroke in, but there's a way round that also.

I suppose if you've already got the bits it's worth a go but since a turbo squeezes the air in in ample amounts regardless of cc's I'd save the cost of a big overbore if you have the same size combustion chambers you can fill 'em with the turbo instead

true,

but the larger engine will make for a nicer engine off boost.