Top end lean out

[Stephen J Jacobs]

Background:
Car - Porsche 914 1.8L has been enlarged  to 1.92L
Injection - Bosch L jetronic Air box is gone and a cold box installed
with a K&N.  And a 4 into 1 header system.

Goal:

Keep stock injection and see if I can get more POWER, Grunt!  But I am
looking at several options, and would like some feed back.

1) release tension on the flapper - problem I see is it only works to a
certain RPM anyway, and if I release this tension I have limited my RPM
range even more.

2) Variable rate of raise fuel pressure valve - one that would generate
more pressure as the vacuum decreased.  Thus increasing the amount of
fuel delivered into the chamber at wider throttle openings.  Problems I
see, the L-jet already has one, but I am not sure how much change it
actually makes.  And there is a possibility the injectors are at max flow
with the stock for the injector pulse width.

3) Tricking the CPU to increase the injectors pulse width.  Two ideas,
install a variable resistor onto the cylinders head temp sensor to make
the engine think it is cold.  Or install a variable resistor into the
line coming from the air flapper to increase the pulse width again.  I
know this one works since I had a defective air flapper that had such a
high resistance it caused the engine to run really rich.

And what would be really nice with the last two would be able to switch
the settings back to stock easily after an event.  If I could install a
switch and hardwired the resistor value I found worked best, it would be
nice.

Also does anybody a have any information on applying a MAP sensor to this
circuit?  I have seen bosch notes on a barometric sensor for the L-jet
that was an add-on for High altitude climates.  I would not worry but
next year my schedule takes me from close to 600ft above sea level to
1300 ft, where I have to run an event.  It would be nice to add this into
the circuit.

Or should I just switch to another system?

Take Care,

Stephen Jacobs
SJacobs914 at Juno.com