Turbocharging a CMFI engine

[Mike Pitts]

Hi,

I'm still looking into turbocharging my CMFI engine. I received my
service manual from Helm today (oh goody goody!)

WOW!  This friggin PCM is complex compared to what I'm used
too working with!!!   The DTCs go up to 82!  Geez!  And who's idea
was it to implement J1930 and change all those nice terms I've
finally learned by heart, like ALDL, ESC, and such?  Okay, enough
griping.  :)

After reading a bit, I have a few of new concerns about this engine's
ability to take forced induction:

a) The fuel pressure regulator is fixed at 55 PSI.  It isn't connected
to a manifold vacuum/pressure source like most other regulators I'm
used to.  On turbocharged cars, this 1 pound of fuel pressure increase
for every 1 pound of boost is essential.  I wonder if a vortec FMU
would simulate this functionality well enough?

b) The system uses poppet valves fed by a central injector.  I am
concerned the boost pressure in the manifold may force the poppet
to open (raise the ball from it's seat).  I can't think of an easy solution
to this occurance, should it happen.  Does anyone know how much
outside force is required to open a poppet?

c) The central injection unit is specialized and non-serviceable.  Is
there any way to increase the amount of fuel the system injects at
any given pulse width and fuel pressure?  (ie: make it act like a larger
injector)

Are there any  aftermarket forced induction applications running on
CMFI engines?  If there are, does anyone know how they address these
issues?

The more I look at this, the more the idea of just tossing on an
additional injector and controller in the up-pipe becomes appealing.

TIA!
-Mike
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Mike Pitts
Delray Beach, FL
mpitts at emi.net
http://www.emi.net/~mpitts/mike.htm
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