Twin charger project?

[corylang at dccnet.com (Cory Langford)]

Okay,  

This is a currently a theoretical question for those who have been dabbling
in the boosted engine area.  I know there are more than a few of you out
there :)

I have a wild idea for my next project.

I have sitting in my garage right now a mk1 roc with a g60 conversion that
I am finishing cleaning up the install and correcting some of the issues
from previous owners.  I have a mk2 turbo 8V and a spare 8V engine already
turbo'd (it was going to be the engine I transplanted into the mk1 body I
found, but I lucked out and found one with a g60 already installed)

So, the wild idea came to me last night:  Why not a twin charged roc.

Take the supercharged g60 engine and ADD a turbo system to it (instead of
replace the charger with a turbo as most people do).

I know for a fact that the early supercharged MR2's had a turbo kit that
supplemented their charger turning them into a twin charged car.

I figure engine management should not be that much different as boost is
boost as far as an engine is concerned.  

What do you think?

My first real thoughts on this is which way to route the boost.  Do you go
turbo first and from the turbo to the Super Charger and then to the intake
(inter coolers in there somewhere of course)

Or do you go Super Charger then turbo then intake?

First intake is Super Charger in front of turbo, as the SC is directly
connected to the engine, where as the turbo is basically free wheeling.  If
the charger pressure at the intake is greater than the turbines are
spinning I figure you just get a backwards effect on the turbo (the intake
spins the exhaust side faster and sucks out the exhaust gasses) until the
turbo spools up and supplies more boost.

If it was the otherway around I figure the SC would get boost pressure and
need to squeeze it through the G60 and that would cause allot of stress as
it is only able to spin at the rate based on the crank connection.

Like I said.  Just musing, but any opinions would make research a little
more fun :)


Cory Langford
'79 Cheap Ass turbo daily driver - RIP
'86 turbo project - The Next daily driver?
'65 Ghia - The next project in the garage