XX4me Posted May 5, 2012 Share Posted May 5, 2012 Hank what electric pump are you guys using? Mine crapped out on me so I need to look into a replacement. Quote Link to comment Share on other sites More sharing options...
HANKSXXX Posted May 5, 2012 Share Posted May 5, 2012 Walbro 255 for the FI bikes... The Bosch 044 is also very popular with the busa guys... Is your pump an universal (external) in line or (internal) in tank? I'd consider 50 lbs pressure at idle with an additional 4 lbs added per lb of boost that you would anticipate up to the maximum boost pressure as the minimum requirement for pump output. I grabbed a quick flow chart comparison on the Walbro's to give you an idea of the different models ... There are some better charts available but this should give you the idea. Note what happens to flow and pressure.... http://www.gnttype.org/techarea/fuelsystem/walbroflow.html What FPR are you using? Quote Link to comment Share on other sites More sharing options...
XX4me Posted May 5, 2012 Author Share Posted May 5, 2012 Walbro 255 for the FI bikes... The Bosch 044 is also very popular with the busa guys... Is your pump an universal (external) in line or (internal) in tank? I'd consider 50 lbs pressure at idle with an additional 4 lbs added per lb of boost that you would anticipate up to the maximum boost pressure as the minimum requirement for pump output. I grabbed a quick flow chart comparison on the Walbro's to give you an idea of the different models ... There are some better charts available but this should give you the idea. Note what happens to flow and pressure.... http://www.gnttype.org/techarea/fuelsystem/walbroflow.html What FPR are you using? I'm running the Bell Multi-role FPR. The pump is external. When I set this up I read that injectors start suffering and risked possible failure past 100lbs, using your formula I'd be at 122lbs of fuel pressure. Whether the failure bit is true I don't know but I set my fuel pressure at around 27lbs at idle with a maximum of 90lbs or so at 18psi boost. I noticed recently that idle pressure had dropped somewhat and then it just crapped out and went to 18 lbs few days ago. Heres a link to a pump through Summit that meets the pressure requirement Pump Quote Link to comment Share on other sites More sharing options...
HANKSXXX Posted May 5, 2012 Share Posted May 5, 2012 I see what you are saying but have to ask if the standard fuel pressure for the BB is 50 lbs at idle, what happened when you turned it down to 27? I understand your math, just not the way you keep with in the so called "boundaries." I would guess you could set the FPR to only add 3 lbs per lb of boost and try that or have you? Our stuff is lower boost and HP levels than your's so I'd do some exploring, but suffice to say the Busa guys make big power with the 044 and also with BB injectors which is an upgrade for the gen 1 Busa. On paper, you are damned if you do and damned if you don't....lol. Quote Link to comment Share on other sites More sharing options...
XX4me Posted May 5, 2012 Author Share Posted May 5, 2012 I see what you are saying but have to ask if the standard fuel pressure for the BB is 50 lbs at idle, what happened when you turned it down to 27? I understand your math, just not the way you keep with in the so called "boundaries." I would guess you could set the FPR to only add 3 lbs per lb of boost and try that or have you? Our stuff is lower boost and HP levels than your's so I'd do some exploring, but suffice to say the Busa guys make big power with the 044 and also with BB injectors which is an upgrade for the gen 1 Busa. On paper, you are damned if you do and damned if you don't....lol. Nothing really happened. The injectors still function fine I did increase the injector pulse duration via the PCIII. I think the idle may be a bit rougher than stock. Probably due to poor atomization at the lower pressure. Yep, I tried all kinds of different configurations when I set it up. Like you said it's all a trade off. Currently I'm running Honda S2000 injectors (see http://www.cbr1100xx.org/forums/index.php?showtopic=5760) They meant that I didn't have to increase fuel pressure or pulse duration as much as the stock injectors would have required under high boost. Quote Link to comment Share on other sites More sharing options...
HANKSXXX Posted May 6, 2012 Share Posted May 6, 2012 Wish I had a more definitive answer on the pump Forrest, but you are outside normal parameters for me... If I understand Corky Bell correctly, his FPR will allow for a large variation in the fuel pump... Airtex might not be a bad choice... Quote Link to comment Share on other sites More sharing options...
eliXXir Posted May 6, 2012 Share Posted May 6, 2012 If you're just changing the pump, the Bosch will suffice for you, Forrest, that's what I'll be using on the ~350-400 HP trike. Hank, why would he need to change anything other than that in the process? Quote Link to comment Share on other sites More sharing options...
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