Re: TBI vs Port Injected

["nacelp" <nacelp@bright.net>]

> For a relatively mild street engine is a port fuel injected motor going to
> produce more horsepower than the same motor with TBI?

Getting a good flowing TPI is usually$$$, or lots of fabing on a single
plane.

Is this an dry air
> flow versus wet air flow difference or really more related to intake
> manifold design?

The two go hand in hand

> Bruce's crossfire setup is an example of an optimized TBI with a good
> manifold, but would this motor have performed better if it were port fuel
> injected?

The engine was first optimized using single, and dual plane manifolds.  I
doubt the is a EFI manifold that outflows a Weiand 7525 (both in stock
form).  The times/trap speeds were a wash, it was too close to call.  The
TBI had all the best manners in the world.  I know carbs really well so when
I say optimized I'm including idle circuit, transistion, acclerator pump,
secondary air valve, secondary needles, and hangers, air cleaners, etc.
They were both tweaked as far as a *normal* person would go.

> The following is the background for this preceding questions. I am now
> slowly gathering the parts for a "new" 4.3 for my truck(94 m5 s10).  Mild
=
> 96+ 4.3 heads 2.02/1.60 ported polished and coated, GM performance marine
> cam in a non balance shaft block, compression ration is TBD, coated
> Edlebrock headers and catback exhaust. Currently it uses a 16184738 VCM
> (VCMs control both the powertrain and the ABS plus generate the signal for
> the speedometer and possibly other gauges).  My options are;
> Retain the current fuel system and improve or replace the intake manifold.

Can you get a second one?.
What I did was gather several manifolds, and then step by step ground on
one, and alternated back and forth progressively getting wilder, then when I
went too far, backed up to the last manifold design, and then knew it was
nailed.

> Swap the ABS system to a stand alone unit and use a auto tranny calibrated
> 16156647 on a CPI fuel system.
> Find a 1995 16193495 VCM and harness and use SCPI fuel system.  This is
what
> I was planning on doing, but I am currently having difficulty finding
parts.
>   This VCM was calibrated for a M5 and utilized the earlier CPI injection
> system.
> Use the 16184738 VCM to control a Sy/Ty fuel system.  Probably the least
> practical solution.

"Practical" whatz that?
Grumpy
>

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