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Max'd out Walbro 400/450?

Old 08-25-18, 01:02 AM
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Max'd out Walbro 400/450?

What have you guys max'd out your F90000267s at on E85?
Assuming it's properly wired and you have enough injector. Just trying to figure out my fueling situation.

EFR8374 21psi spring
2200cc 4x
6an Feed/Return

Do you think a single F90000267 will do the trick?
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Old 08-25-18, 05:51 PM
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On e85? Hahaha, not even close! At 21psi of boost and 43.5psi base pressure the fuel pump sees 64.5psi in which the Walbro flows about 95 gals/hr = 6000 cc/min.



So in a perfect world, you're getting 6000 cc/min on your 8800 cc/min injectors which means the fuel pump runs out at 68% duty cycle (on all four if they are equal) at 43.5psi.

This isn't including ANY losses in the system, which there are quite a few.

I would suggest two Bosch 044s at 70psi base pressure.
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Old 08-25-18, 06:11 PM
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You have to consider that the fuel flow requirements for alcohol is a lot more than gasoline.
For E85 you need about 37% more flow.
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Old 08-27-18, 08:57 AM
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You should be okay at 21 psi.



Here’s my math:
  • 21psi = 2.42 atm-a
  • ~200whp (NA) * 2.42 = 485whp
  • 485whp * 0.13 = 63.14 lb/min turbo air flow
  • 63.14 * 0.10 = 8.84 lb/min fuel flow (10:1 AFR, +40% for ethanol)
  • 8.84 * 60 = 530 lb/hr
  • 530 / 6.5* 3.79 = 308.9 LPH
This is assuming zero losses.


A Walbro 400 at 13.5V and 4.5 bar flows ~350 LPH, so you still have some head room


I made 540whp through a single Walbro 400, but at 28psi of boost and the fuel pressure was about 15-20psi below what it should have been! The only caveat- that was through stock hardlines BUT on pumpgas.



IMO, The 400/450 pumps are the best bang for the buck. Quiet, powerful, cool, and cheap. It is difficult to fit two in-tank, but there are some aftermarket options for pump hangers.
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Old 08-27-18, 09:45 PM
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Non hellcat version at e77 or higher starts to run out of pressure above 15 psi( 430rwhp range). E55 is fine to 460range. At the 500rwhp mark( 17/18 psi) you will be down 6 psi on e55, and down 10 plus psi on e77. This is my experience with the 8374 iwg on this combo with a good 40 cars in the past year. Installing the new hellcat version tomorrow, will tune in two weeks on another 8374 iwg.



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