# \#fueling

**URL:** https://community.tunersguild.com/tag/fueling/99.md

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## [Is rail pressure +10% safe on diesel — which zones and why?](https://community.tunersguild.com/t/is-rail-pressure-10-safe-on-diesel-which-zones-and-why/118)

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**Author:** [@ThomasPirowski](https://community.tunersguild.com/u/ThomasPirowski)\
**Replies:** 0\
**Last updated:** [May 1, 2026, 6:47pm UTC](https://community.tunersguild.com/t/is-rail-pressure-10-safe-on-diesel-which-zones-and-why/118 "2026-05-01T18:47:15Z")

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A +10% rail pressure increase on diesel delivers only about 2.5% efficiency gain — nice, but not dramatic. Safe in mid-RPM / mid-load zones where the pump has capacity. Risky in the max-fuel corner where the pump has onl…

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## [How do I compensate a 2.0 → 2.5 gasoline displacement swap on a DENSO ECU?](https://community.tunersguild.com/t/how-do-i-compensate-a-2-0-2-5-gasoline-displacement-swap-on-a-denso-ecu/83)

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**Author:** [@ThomasPirowski](https://community.tunersguild.com/u/ThomasPirowski)\
**Replies:** 0\
**Last updated:** [April 25, 2026, 6:16am UTC](https://community.tunersguild.com/t/how-do-i-compensate-a-2-0-2-5-gasoline-displacement-swap-on-a-denso-ecu/83 "2026-04-25T06:16:28Z")

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A 2.0 → 2.5 displacement swap on a DENSO ECU requires two separate scalings, not one. Scale MAF down 15-20% (not 25%) to prevent “too extensive flow” error codes without overcompensating EGR recirculation. Scale MAP-driv…