Edelbrock TBI conversion to PI

[Shannen Durphey]

David Sagers wrote:
> 
> Last night I was looking thru the new Jeg’s catalog and saw the Edelbrock
> kit for converting a GM TBI to a port injection system, includes manifold,
> injectors, fuel pump...
> 
> The description says that it uses the TBI computer.  Now Edelbrock makes
> some fine intake manifolds, but the total cost on the kit is some $1100.
> 
> Since I already own most of the parts for a TPI intake, I am  wondering how
> to make the TBI computer for my ‘92 SBC Suburban fire all eight injectors if
> I install the TPI.  Is it as simple as a harness that plugs into the
> existing TBI harness or is there more to it?
> 
> Seems that a computer designed to drive two TBI injectors would lack
> something necessary to drive eight TPI injectors, maybe that’s why the kit
> is $1,000.
> 
> What else to I need to change to make the TPI conversion?  Would I be better
> off buying the Painless Wiring harness and using a TPI computer instead of
> the TBI computer?

There might be some information in the archives, I've looked into this
a little.  Edelbrock uses a stock ECM, but they will send a new Eprom. 
There isn't much changed in their calibration from the factory cal's
I've looked at. These were for the 91 and older 747 ecm.  
 I was told the injectors plug into the factory harness.  They are
driven by
the stock injector drivers.  I suspect they are the same as the
parts used in the Pro-flo system.  I was told the Pro-flo injectors
are Marelli units, and measure 17 ohms each.  If I remember the
formula, that should work out to around 4 1/4 ohms/bank of 4.  What is
the resistance of the TBI injectors? 

Fuel pump from a pfi vehicle should be sufficient for the conversion.
Edelbrock tech help has been somewhat friendly to a couple of people
I've spoken with, so you might give them a call.  

I'd use a complete TPI setup, including the ECM.  I really think the
long runner TPI manifold should be used in the trucks.  If it were
combined with a Crane Compucam designed for torque, that would make a
really strong tow vehicle.
Shannen