255lph Limits

[brady_f]

Seems there is conflicting information on the web on how high you can push a pair of 255's in a return setup. Looking to make around 700rwhp on E85 and currently have a Fore system installed with 2x Walbro 255's. Will these get me there or do I need to look at upgrading pumps?


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[broke7]

what size injector?

Im not an E85 user due to my location, but I had looked into it. At my power level 744whp My 255's would of been close on E85, they work good on gas. I have heard of guys using a BAP on the 255's for a cure, or least to run them at 14.5v constant vs what the alternator will trickle down to once its warm.

If your in dought just go with some 340's

 

[brady_f]

what size injector?

Im not an E85 user due to my location, but I had looked into it. At my power level 744whp My 255's would of been close on E85, they work good on gas. I have heard of guys using a BAP on the 255's for a cure, or least to run them at 14.5v constant vs what the alternator will trickle down to once its warm.

If your in dought just go with some 340's

Bosch 105's....so I have plenty of injector. Seems like the corvette guys are getting away with around 700 on E85 with these pumps. Just wanted some feedback before I leave it as-is and run out of pump on the dyno.


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[broke7]

You cant compare the two motors when it comes to fuel flow and dyno's, especially when considering different power adders, cubes, powerbands, etc.

With 105's I would get bigger pumps. E85 takes roughly 30% more overhead vs gas to make work effeciently

 

[cobra187]

Will 340's fit in same fore hat that had the 255's? If so I'm swapping to 340s too.

 

[da28fan]

Just put two 465lph Walbros in mine. Was losing too much fuel pressure at WOT with 255s. To me, not worth the risk of running lean. And even with these big pumps, still drops from 38 to 29 psi at WOT (just came off dyno today). The 465s will fit into Lethal's hat but with some modifications (need to cut off some of that white connector or the pumps will stick out too much and the hat won't seat on the tank. Also, don't believe the numbers Lethal advertises when it comes to e85. Those are numbers on regular fuel at the crank. As broke7 states, you'll need 30% more fuel capacity for e85, and when you figure 15% loss from crank to RW, well, you get the picture. Good luck!

 

[me32]

On the gt500s I run two 255 pumps with bap an 80lb injectors an make 700 on E85.