[tazandjan]

Thought you F430 owners might like to know how the bypass valves work on your car. The bypass schedule is actually fairly sophisticated, and varies with Manettino mode, rpm and throttle setting.

If you did not already know it, your bypass valves are fail open. That means they are spring loaded to the open position and if the system malfunctions (bad solenoid, vacuum leak, etc) they will remain open. This also means that if you want to have your valves open all the time, all you have to do is remove and plug the vacuum lines going to the pneumatic valves themselves. Some Ferraris, like the Maranellos, have fail closed valves and it takes a bit more work to defeat them.

I received this schedule from my German friend Stef, who has a really complete set of technical data on the F430.

Incidentally, the hysteresis refers to an a anti-flutter strategy that has the valves close at a lower rpm than they open, to prevent the valves from fluttering by receiving both open and close signals at the same rpm.

Taz
Terry Phillips