[Gmecm] custom retro carb efi lookalike

[dozierhc at aol.com]

Alan......

The tuning really is dependent on whether the injectors run as a constant pressure drop or not (eg: the fuel pressure regulator has a vacuum/pressure reference or not).
No pictures on that site show a fuel pressure regulator with such a reference, so I will assume it is constant pressure, albeit high pressure) injection.

That said, since all the fuel dumps into the plenum and makes it way to the cylinders via the intake manifold runners, this characteristic is more of a TBI setup than a MPI type of injection, as fuel evaporation, and wall wetting are much closer to throttle body injection than port injection.
The only big difference would be the higher pressure and therefore better stream atomization of the injectors (smaller droplet sizes).

At higher port velocities the fuel probably stays more entrained in the flow stream, but at low velocities it most likely plates out to the manifold and port walls.

So the end result is that it would need tuning closer to that of TBI than MPI for the low speed light load areas, including PE enrichment based on both MAP change and TPS rate of opening.
Also, the cold fueling will be richer due to the wall wetting.

Hank



-----Original Message-----
From: alan mays <truckeez at yahoo.com>
To: Gmecm <Gmecm at diy-efi.org>
Sent: Fri, Feb 24, 2012 6:45 pm
Subject: [Gmecm] custom retro carb efi lookalike







I was checking out the efi retro stromberg 97 from  



http://www.autotrendefi.com/efi_97.html  its got the injectors spraying just UNDER the throttle blade---  so its not throttle body?
 
 if the injectors were spraying just above the blade--it would be throttle body injection--and would have to be tuned as such?
  so the setup is technically port injection as long as the injectors are down stream of the blade --by even a inch,  and has to be programmed as port injection--and use a port efi computer?  



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