Did you guys know that the 2nd generation turbo had some kind of electronic gizmo in its circuit (help me out here, Ed Anderson) that stepped down the voltage on the fuel pump at idle? I ran a voltmeter on my 87 Turbo's fuel pump for a while. I think at idle it was running about 9 volts and then it jumped up to about 11.7 or so at WOT. So I think you're on the right path, Steve. At least you're taking the same route the factory did with its 550 cc injectors.

I used to know the fuel pressure readings that corresponded to these different voltages but took my engine out of the car for modifications about 18 months ago. If I find my records, I'll let you know.

Barry Gardner
Wheaton, IL

Steve Brooks wrote:

One nagging problem that I have is the engine running rich at low power
levels.  I've turned the fuel pressure regulator down to 30 lbs to get it
reasonably lean, but I still don't have enough adjustment.  The higher power
levels have a pretty good mixture on the default tuning.

Right now I'm running the stock 550cc injectors, but I'm considering
changing the primary injectors to 440cc, to help the low end mixture, and
leave the secondaries at 550cc, so that I still get sufficient fuel flow
with the turbo at higher power settings.

My thinking is that the 440cc injectors would allow me turn the fuel
pressure back up to 38 lbs. and hopefully still be able to tune the lower
end where only the primary injectors are supplying fuel.

Does anyone have experience doing this, hopefully with a turbo, or just have
an opinion ?

Steve Brooks


  

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