[PrecisionSound]

I have been reading all day and trying to understand what the limitations of our fuel systems are. I would like to hear from guys with upgraded turbos and what they did to add the fuel needed for higher power levels.

What limits our ability to run straight E85? Is it just the LPFP or Injectors or HPFP?

Why is it that people don't just run bigger injectors instead of adding other injectors? Is it the cost of injectors or the limitations of the pumps.

And is the HPFP capable of flowing the fuel needed to run E85?

I would like to be able to run a larger turbo eventually but as of now I am not fond of the options for adding the fuel needed.

[Mikaeldarer]

Originally Posted by PrecisionSound

I have been reading all day and trying to understand what the limitations of our fuel systems are. I would like to hear from guys with upgraded turbos and what they did to add the fuel needed for higher power levels.

What limits our ability to run straight E85? Is it just the LPFP or Injectors or HPFP?

Why is it that people don't just run bigger injectors instead of adding other injectors? Is it the cost of injectors or the limitations of the pumps.

And is the HPFP capable of flowing the fuel needed to run E85?

I would like to be able to run a larger turbo eventually but as of now I am not fond of the options for adding the fuel needed.

E series actually come with decent HPFP, but LPFP and HPFP are ultimately the two things holding back our fueling systems. Our vehicles are DI, so only way to upgrade "injectors" is the go PI.

https://en.wikipedia.org/wiki/Gasoline_direct_injection

The highest E85 blend I've been able to run without any problem is E30 on stock fuel system.

[PrecisionSound]

Thanks for the info. I understand the concepts but just wondered why there are no options for direct replacement higher flow rate parts used. What about these? Has anyone looked into them? They also offer a higher flow rate HPFP.
http://www.xtreme-di.com/index_files/XDI_BMW_KDI.htm

[bahn]

Injector isn't the issue. With an upgraded LPFP the HPFP becomes the limiting factor. It can't keep up with the volume demand, when that happens the rail pressure drops and the engine breaks up.

[prima_materia]

Fuel It Stage 2 LPFP and Fuel It TBI, both of those would give a solid setup for fueling I'd imagine. Only thing is that TBI is bulk distribution, versus PI which is per-cylinder distribution.

I'm still running the stock HPFP @ 100k. I run anywhere from 40-50% e85 mixed with 93. Once I go PS2 I'm definitely going to grab the Stage 2 LPFP and TBI.

[JETmn]

There are several PI options that are almost the same price as the fuel-it TBI. I like fuel-it, but they need to bring their prices down a bit since there is competition now.

[prima_materia]

Originally Posted by JETmn

There are several PI options that are almost the same price as the fuel-it TBI. I like fuel-it, but they need to bring their prices down a bit since there is competition now.

This.

Fuel-It is definitely pricey. MMP with their $600 setup now, hopefully Fuel-It takes notice and drops their PI kits a bit.