2 Questions about GM-TBI

[FIScot at aol.com]

   Subj:   2 Questions about GM-TBI
   Date:   95-12-26 14:42:33 EST
   From:   blwalt at ecsis.ecsis.net (Brandon L. Walters)


 >  1. Is anybody using GM TBI injectors in their projects? They seem quite
 >  rugged & I wonder what all you can do with them.

    I am in (slow) process of trying to use them.  This was triggered by an
    article in Sept '91 Truckin' magazine.  Turbo City had put two dual
    TBI's on a two-four barrel intake manifold. It looks slick, and has
    plenty of air flow ability.  I called and they said you HAVE to have a
    custom chip (of course!).  That meant a DIY'er had to figure out the GM
    TBI computer, if you wanted to use it.

    That being done, I still have two questions.  Will the stock peak-and
    -hold injector drivers like having double the load if I parallel the
    the TBI injectors?  Turbo City claims to use the stock truck TBI ECM.
    The if drivers will live, maybe a little extra in the injector voltage
    compensation tables (or similar) will make up the difference in
    injector turn-on time?  Any comments?

    Also, the firing order.  The intake is an Offy 360.  It is similar to
    an open plenum with a divider in the middle.  This puts cylinder #7
    just 90 crank degrees after cylinder #5, with another 630 crank degrees
    until cylinder #5 fires again.  Will this set-up have a big mixture
    distribution problem? That is, will cylinder #5 receive most of the
    fuel that is injected?

 >  2. If you want to fabricate your own tuned intake runners for a 350, what
 > is the best way to replace the lower part of the manifold? The TPI style
 > setup is not what I had in mind.

    TPI has long runners.  This makes great mid-range torque.  Great for
    gas mileage, and I imagine a great tow-motor in a truck.  If you want
    lots of upper RPM HP, then some other form of manifold is required.
    This is part of the reason for my persuing the dual TBI's.  They will
    be used on a much shorter intake manifold, that was meant for wet-flow.

    A tunnel ram is also meant for wet-flow, maybe you could adapt the base
    of a tunnel ram manifold, with your own custom plenum on top?

    Of course, I have to get an SBC to mount this on..... The present V-6's
    in the famaily vehicles just won't do.

    Thanks, Scot Sealander   FIScot at aol.com