Engine spec for turbo

[Graham]

Ok i've almost got my chim back together with a stock 3.9/4 motor and a 14cux.

The plan is to get that running then swap over to an emerald and coil packs.

The stage after that is to go 4.6 turbo.

Ive got a x-bolt 4.6 block and crank that im having fettled with an overbore so need a set of pistons and ill probably change the rods too. Ive got a selection of stock heads to play with 4ltr and 4.6

Any suggestions on how to go, its a road car not a track monster im after
G

[Boosted LS1]

You don't need to change the rods. All you need are some low compression pistons and then you can aim for high torque and decent bhp within sensible rpm's.

[Graham]

how about using 14 bolt heads from an early 3.9 would that get the comp ratio in the right range? when used with the 4.6 rods and piston?

ive got a selection of 3.9 14 bolt, 10 bolt and 4.6 heads ive been collecting...

i assume i dont need anything very wild cam. wise,as presumerably a turno doesnt want overlap

g

[phazed]

I've got a set of vgc standard 4.0 pistons if you're interested?

[Graham]

dont the 4.0 pistons give a higher cr than the 4.6? when i was intending to go NA the plan was 4.6 block/crank/rods/heads and 4.0 pistons.. the block needs a rebore so I need oversize pistons and the 4.0 only seem to come in std. 4.6 do come in oversize and are very cheap, and the strongest std pistons iirc..

so my current thinking is a fairly stock 4.6 bottom end just nicely put together and lightened and balanced. real steel do a turbo cam, decent timing gear, lightened & balanced flywheel

heads just double valve springs,tidied up around the ports and matched to the inlet manifold, 45mm base and trumpets,72mm plenum and eann or powers turbo kit..

all run by my emerald ecu


does that make sense? iirc the stock 4.6 is 9.35:1 isnt that a suitable cr to start turboing?

[phazed]

I meant 4.6 pistons