size of pressure pipe from SC to fuel pump

[IMJ]

Could someone tell me the correct size of the pressure pipe from the super charger to the fuel pump on an R2. My super charger has a 3/16" tube(a 1/4" barb at the tip). My fuel pump has a 1/8" pipe thread hole for the elbow. The parts book calls for a 1/4" pipe nut at the fuel pump. I am also curious to know how the extra pressure to the top of the fuel pump diaphragm boosts the fuel pump output.

regards,

Jay

[StudeRich]

It EQUALIZES the fuel pump pressure.
It merely prevents the Carb. from running out of fuel at higher RPM when the Supercharged pressure at the Carb. would exceed the Fuel Pump pressure.

StudeRich

[41 Frank]

!/4" tube from fuel pump to area next to supercharger then 1/4" hose rest of the way to barbed fitting.

Frank van Doorn
Omaha, Ne.
1962 GT Hawk 4 speed
1963 Daytona Conv
1941 Champion R-2 Powered Streetrod

[IMJ]

Thanks to the both of you. That answers both questions.

regards,
Jay

[Mike]

The spring, on the diaphragm in the fuel pump normally controls fuel pressure. It gives at maximum designed pressure, instead of moving the diaphragm. On supercharged models, the boost reference acts to reinforce the spring, increasing fuel pressure with boost.
By the way, the earlier Golden Hawk models have a slightly smaller boost reference line, 3/16"; and a smaller barb at the supercharger.