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Max power from fuel system with and without PI

Discussion in 'N54' started by Reaper0995, Jan 17, 2017.

  1. Reaper0995

    Reaper0995 Specialist

    Pretty simple question, but I can't find a definitive answer. I have a stage two ******* lpfp, would I be able to make more power with PI or would it be the same as just the DI by itself? In a nutshell, it looks like there are various power levels for DI only with the stage two pump, but if I have PI and the stage two, does hat open up more headroom..? Or do I need to upgrade the lpfp along with PI?
  2. Dave@Fuel-It!

    [email protected]! Corporal Vendor

    There are a fair amount of factors that need to be considered, which is why you are getting multiple, and different answers.

    Regarding fueling hardware, our standard stage 2 LPFP supports ~550 whp on 100% e85. The HPFP however only supports ~420-430ish whp on full e85. If you wish to achieve the most power, and utilize full e85, the HPFP needs to be supplemented. It is this very reason some choose to run blends, e30, e40, e50 and so on. PI will open up more power potential, that being said feeding the 6 additional injectors in the PI rail, does put some added strain on the LPFP (it's really a give & take relationship here). To answer your question, yes, PI + stage 2 will open up more headroom. The limiting factor in your fueling will no longer be the High pressure side, but now the LPFP.

    It really comes down to a few things, power goals, and budget.
    Last edited: Jan 17, 2017
  3. doublespaces

    doublespaces Administrator

    2009 E93 335i
    Max power is likely to happen on race gas or pump gas and meth or a wet nitrous setup of some type. If you're talking ethanol then what Dave said.
  4. Snelson3003

    Snelson3003 Sergeant Vendor

    On E85 i would say you are limited to 490WHP running the Stage 2 LPFP and a lean AFR target of 12.9.

    Outside of that the HPFP wont handle anything more. Ive tried it with 3 new ones and the results are the same on a OEM pump build.
  5. Reaper0995

    Reaper0995 Specialist

    Thanks for the replies, definitely helps simplify this.

    Also this is a great forum, by far the best attitudes overall of all the forums I've seen for this platform!
  6. To be fair from some results I've seen just because of less strain in the HPFP side e60-e70 would be preferable in some aspects.

    But, overall just adding a little e85 will go further than you'd think. E30-E40 on a rather stock car with stage 2 lpfp, the car seems to love it.