September 13, 2020

We are going to break down a rough guide on what size fuel injectors to run for pump gas & e85 turbocharged 13B rotary engines. Base fuel pressure is assumed at 5 bar( 43.5 psi) for the calculations below.  Please note that base fuel pressure is measured with the engine running & full voltage applied to the fuel pump, but the vacuum hose disconnected to the fuel pressure regulator.

We will start with pump gas first;

  • 300 to 400rwhp we recommend 4X ID1050Xinjectors and at least a 340LPH up to 460lph fuel pump. 
  • 400 to 600rwhp we recommend ID1050X primaries and ID1700X secondaries ( pump gas with methanol injection here above 450rwhp) . One 525/535lph hellcat pump is recommended

E85 powered cars;

  • 300 to 400rwhp on E85 we recommend 1050Xprimaries and ID1700Xsecondaries with at least one 460lph worth of fuel pump. 
  • 400 to 600rwhp we recommend the ID1300Xprimaries and ID2600XDSsecondaries with two 460lph fuel pumps( or bigger ) 
  • 600 to 1000rwhp we recommend a 6 injector fuel rail system with 2X ID1300X primaries and 4X ID2600XDS secondaries, twin 535lph pumps will support about 900rwhp safely, 3X 460+ size pumps will do over 900rwhp on E85. 

Pump only guide/notes:

Generally one 460LPH fuel pump will get you to 530rwhp on pump gas, but only 425rwhp on E85, and 450rwhp on E55( with no pump pressure loss). 

The Walbro Hellcat 525/535 pumps will do 490rwhp on E85, 520rwhp on E55. 

If you are running methonal auxiliary injection on top of pump gas the walbro 460 will support 600rwhp easily, and the hellcat 700+rwhp. As long as you are running a big enough methanol jet. ( m15-20 size). 

Anytime twin pumps are run you should be upgrading to a 8an return line, even if the pumps are staged( recommended). Its always best to trigger the 2nd pump around 10-15 psi via a programmable standalone ecu. 

The most restrictive part of the fuel system is the fuel filter, and we strongly recommend the IDF750, especially for E85 cars since it has a 6 micron cleanable fuel filter. E85 fuel filters should be cleaned every 6 to 9 months. 

Please note that the OEM wiring will not support any 400+LPH fuel pump, even the OEM bulkhead wiring cannot support the Amp drupgraded fuel pressure regulatoaw. The OEM FC/FD fuel pressure regulators will not support more than 255LPH either, an upgraded unit, like the turbosmart FPR is a must. 

If you have a 20B 3 rotor, just add 33% to all of the numbers above. 




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