[Diy_efi] CIS EFI via Fuel Pump PWM

[Stephen Webb]

> Somewhat true.  Even Bosch admits this in their literature and cites it as a 
> benefit of the hot wire and hot film air-mass meters.  Numbers vary all over 
> then place, but one ex factory engineer who did dyno test on L-jet motors, 
> with and without the meter, was surprised to find a 15% increase in output.  
> Having had both L-jet and CIS motors, I'd guess that CIS is even worse than 
> the L-jet meter.  I have an L-jet engine that I converted to a speed density 
> system, which was enough to convince me.  Others may need sugar coated 
> potions.

I wonder what difference, if any, a turbocharger makes for this problem.

In my setup the turbo sucks through the FD, (hopefully) compresses the
air, and then on to the intercooler/TB/manifold.  Since the boost pressure
is referenced to atmospheric pressure, I'm thinking the pressure drop
across the air flap may not matter [so much]-- the turbo may have to work
a little harder to maintain a given pressure, but in doing so it
"recovers" this pressure drop. 

Am I off base here?

For an N/A car, if the air flap *is* restricting airflow, would you expect
to see the vacuum gauge indicate some sort of pressure drop due to this
restriction? 


-Steve



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