Which Intake

[Gary Derian]

Porsche 917-30's from way back had a mechanical linkage to butterflies on
the plenums which opened to atmosphere at part throttle.  The setup had
throttles in each port, two turbos, each feeding a plenum.  The butterflies
vented pressure when the throttle was suddenly closed.  The mechanical
(alpha-n with boost sensing) fuel injection they used did not care if air
was vented.  They may also admit air as the throttles were opening (not at
WOT, though) or they may have been set up to vent some pressure as the
driver was approaching full throttle.

Gary Derian <gderian at cybergate.net>


>
>The old Accel draw thru carb turbo adapter kits had this feature--they
>called it a "priority valve"--twenty years ago.
>
>Regards, Greg
>
>Allowing the turbo to
>>spin in a vacuum after closing the throttle means instant boost when the
>>throttle is nailed. Refer to TURBOCHARGERS by Hugh Macinnes.
>>    TIA
>>    Wayne
>