The IA method modifies the computer to accept higher than
stock boost levels as "OK" without shutting down the fool
delivery system. This allows the protection for over-boost
to remain, although triggered at a much higher level.
The IA mod also bumps up the timing (actually reduces the
amount of retard as a function of boost) and also increases
the rev limit cutoff point. One actually increases the boost
(at least in older turbos) by installing a stiffer waste-
gate spring and/or making the wastegate adjustable and
cranking up the spring tension. I did both, made the
wastegate externally adjustable (simple really) and
installed a stiffer spring that allows about 10 PSI to
17 PSI adjustable range. I'd like to find an even stiffer
spring. I typically run at 15 PSI on the street all the time
and the stiffer "green stripe" spring is very compressed by
the adjuster at 15 PSI. I want an even stiffer spring so I
don't have to crank up the tension so much. I think the AI
mod also increases the timing advance when off boost.
-glen
