Mmmm; FMU are not the best tuning aid.

I installed a Hann Turbo kit on a 2003/4ish Cavalier a few years ago. Local guy bought the kit from Hann and wanted a hand to install it.

Overall kit was not bad, just a few cheap ars component that we upgraded.

The kit came with larger Injector and a FMU. Gig was to tune it using a A/F Gauge and to bring up or down a Set Screw on the top of the magical FMU. Archaic if you ask me.

The idea of larger Injector is to provide more Fuel when needed. FMU do not remove Fuel at lower RPM/Throttle Setting. They somehow pull Fuel and add some under Boost.

Best would be to run a larger Fuel Pump, run an Adjustable Fuel Pressure Regulator to bring Fuel Pressure to stock pressure, larger Injectors to provide Fuel at higher RPM/Boost Pressure and a means of controling the larger Injectors.

S-AFC or something like the Greddy E-Manage would be the best. And as a reference you should defenately run a Wide Band.

Any less of a set-up would be getho!!!

Ghislain.