To put what Bill said into context... the S3 pump fills a swirl tank that feeds a pair of Bosch 044 pumps... IIRC Bill calculated the swirl tank would potentially empty in around 45 seconds at full chat...
er, yea.. that makes more sense
S3 in tank fills 2ltr swirl pot, off which feeds 2 x Bosch 044, which blow thru -8 to the fuel rail(s) up front to Aeromotive FPR and returns to swirl pot in -6 and then back to tank.
3.3ltr no load gives me a limited limt on full chat.. 40 odd secs as tuffty says (by calculation never tried it) before emptying the swirl pot.
3.3ltr no load is best flow conditions remember..
A lot of BT builds need healthy in tank S3 pump + inline DA-31/bosch 044 as well...
My S3 pump has been in my tank since 2003 when I was IHI'd way back, on low 300bhp and was adequate then