Whats That “Click” From The Engine Compartment At 4,000 RPM?
[AV] There is a rather little-known fact about the fuel pump of the NSX. It is actually a two speed fuel pump. The first or low speed mode puts out about 42 psi. Under high load conditions above 4000 rpm, the pump switches to it’s high speed mode and pumps out 84 psi (give or take a few psi). The switch is activated by a relay behind the seats underneath the panels. Take note that the high speed mode does not kick in until 4000 rpm, at part to full throttle in moderate to heavy load conditions. Randy Marchetti has pointed this out to me when we were test driving his Nitrous Oxide injected NSX, and that his NOS kit is tied in to the fact that the fuel pump is dual speed. As a safety measure, his NOS kit does not turn on unless the high speed mode of the pump is activated, thus limiting the activation of the kit to above 4000 rpm (lessening the stress to the engine by preventing high internal pressures at excessively low rpms) and insuring adequate fuel supply whenever NOS is activated.
Related Questions
- When Ive been driving around a while and come to a red light or stop sign, the engine rpm drops to almost nothing, nearly dies and then recovers. Have I done something to damage the car?
- Why does volumetric efficiency increase with engine rpm in internal combustion engines?
- Can the EED-5 be installed in the engine compartment?
