The V8 Owners Forum -

just testing the water as they say,
will the present cam i have fitted be ok to use with a turbo?

Any cam can be used with a turbo when you have EFI. The question is what power delivey/spool up characteristics do you want.

Most turbo cams are low overlap to try and get a quick spool up and a flat torque curve to add boost to. But that doesn't mean it's the right or only way to go.

Hi Tony
looking at the spec of the cam it looks a good choice, not too much duration, nice wide lobe seperation angle nice lot of lift on the exhaust side, a good starting point. If I were developing the car for a turbo aplication then I would probably go for 114 to 115 deg LSA , advance it a couple of degrees, if the heads can make use the extra lift on the inlet side then go to higher ratio inlet rockers and add about 3 or 4 degrees of exhaust timing though you should find out the flow of your heads against valve lift before you make any final decision.
All this would get the exhaust valve opening about 8 to 11 (crank) degrees earlier which should get the turbo spinning up quickly and still leave the inlet closing at about the same point which should keep it efficient.
Mike

cheers guys,
fingers crossed the turbo set up comes off now
if it does looks like no show for the capri this year as i will be in the garage playing

Can't see why sticking in an extra head gasket on each side and sorting out a bit of exhaust and inlet plumbing should lake more than a weekend
Mike

im running 9.35:1 comp ratio +/-
this would be ok for around 5psi boost no?
or do i need to lower the comp ratio???

Tony - I spoke to V8D about my planned 4.6 build for next year, they said 9.35 pistons should be fine on 5-6psi with a good engine build.

So then, pray tell me what are your plans for turbo'ing? Single? Twin? Intercoolered?!?!

Its all gonna be good no matter what tho eh Tone?!

I would think 9.35 CR would be safe with about 5psi, add an intercooler then I think you could run 7 may be 8 at a push.
I'll look out some of the books I have at home this evening and see what they say but I would think you would be safe.
There are those fare better able to advise on this than I though.
I presume most of the rest of the car can stay as it is? the injection, heads etc. if you are after serious power then I would think you will need 12+ psi in which case you will need to drop the CR, with the rover you ain't short of low CR pistons to choose from .
Mike

the plan is (if the set up comes off)
run the single turbo on my present engine as that has been so reliable mechanical wise, with the possibility of an intercooler, have thought about using water injection too as i think the vems has an output to drive a similar thing, i may be wrong here
with around 5-6psi boost, and use the nitrous to aid turbo spool up then turn off at a set boost level.
im not looking for a mega set up as turbo charging is new to me so im looking at starting low and work my way up

if i get on ok with it i can then look at playing with my spare 3.9 engine in the future for more ponies and boost

Heard today it looks like the turbo engine is a no go
back to the drawing board again