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that's 39 g/hr at 85 psi, vs GSK's 25 at 40 psi ?? Posted by Kevin K [Email] (#374) [Profile/Gallery] (more from Kevin K) on Fri, 9 Mar 2001 22:34:18 In Reply to: Static test with stock fuel pump, Beaudreau, Fri, 9 Mar 2001 19:25:55 Members do not see ads below this line. - Help Keep This Site Online - Signup |
that does sound a bit high ....
more math:
if test was 85 psi rail, into open bucket, then drop was 85 psi, and injector is likely rated 44 lb/hr at 3 bar ot 43.5 psi drop. Sq-rt of pressure ratio says flow will be 1.40 X more, thats 62 lb/hr per injector, for a total of 246 lb/hr, or 39 g/hr.
at bsfc = .55, thats 246/.55 = 447 hp potential for pump at 85 psi line pressure. need 165 lb/hr for 300 hp.
note you will not likely get this flow due to supply line pressure drop, filter losses, and voltage drop at the pump at high pressures. But each can be fixed.
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so if you run 20 psi boost, 85 psi rail (RRFPR), that's 65 across injector, for 1.22X big inj rating at 3 bar. For 300 hp, inj's at 85%, you need (165 lb/hr) / ( .85 x 4 ) = 48.5 lb/hr inj's. May need more than 6K revs to get the air in 2L.
unless done properly, that .55 factor goes up with inefficency.
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