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BMW B58 · E30 Blend

BMW B58 E30 Tune

M140i · M240i · 340i · 440i · 540i · 740i and 7 more

A B58 E30 tune is a calibration written for a fuel that is roughly 30% ethanol by volume. Ethanol's higher latent heat of vaporisation and higher effective octane cool the charge and resist knock, which lets the calibration hold more ignition advance and more boost at the same safety margin than pump fuel allows. In exchange it needs more fuel mass for the same air, which is what sets the ceiling on a direct-injection-only B58.

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Platform
B58 Gen 1 · B58 Gen 2
Sold as
Stock-turbo B58 calibration
Base calibration
$400
Revisions
Log-based, included

B58 E30 Blend, by generation.

Gen 1 (B58B30M0) and Gen 2 (B58TU) run different DME software, with different boost, fuelling and torque structures. A Gen 2 file does not belong in a Gen 1 car, and the 540i, M240i and Supra span both generations by model year. Each row is the catalogue calibration this e30 blend build is sold as, at its live price, with the add-ons that apply to it. What the car needs first is listed further down.

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B58 E30 Blend calibration

Choose your generation to carry it into Find Your Tune. Not sure which you have? Find Your Tune identifies it from the car.

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Which cars it applies to.

B58 Gen 1 and Gen 2 cars running a mixed ethanol blend rather than a flex-fuel sensor. If your car has a content sensor and you want one file that adapts across blends, the flex-fuel path is a different calibration.

  • B58 Gen 12016-2021M140i, M240i, 340i, 440i, 540i, 740i, X3 M40i, X4 M40i, Toyota GR Supra 3.0Chassis and years
  • B58 Gen 22019+M340i, M440i, M240i, 540i, 840i, Z4 M40i, Toyota GR Supra 3.0Chassis and years

What the calibration changes.

  1. 01

    Ignition advance re-optimised for the fuel

    E30 raises the knock threshold, so timing that would be marginal on 93 becomes usable. Advance is added where your logs show the headroom is real, and the knock-correction channels stay the arbiter rather than a theoretical octane number.

  2. 02

    Fuel mass and rail pressure targets

    Ethanol is less energy-dense, so the injectors and high-pressure pump move more fuel for the same power. Fuel targets and rail-pressure demand are raised accordingly, and boost is capped at whatever the fuel system can actually sustain rather than what the turbo could flow.

  3. 03

    Boost targeting against the new knock margin

    With detonation no longer the first limit, boost targets can be lifted in the band where the compressor is efficient. On the stock turbo the payoff is mostly a fuller, flatter midrange rather than a higher peak.

  4. 04

    Blend tolerance built into the map

    Real-world mixing drifts. The calibration is written with margin for a blend that lands a little under target, so a tank that comes out at E27 instead of E30 does not put the car into knock.

What your car needs first.

  • A repeatable way to mix: the same pump, the same ratio, every time
  • An ethanol content tester, or fuel bought at a known-content E85 pump and mixed by volume
  • Fresh plugs — ethanol maps run more advance, and marginal plugs show up immediately
  • Healthy high-pressure fuel delivery; ethanol asks for roughly 30% more fuel mass than gasoline for the same air
  • A second pump-fuel map if the car is ever driven somewhere the blend is unavailable

What to log.

  • RPM and vehicle speed, so every other channel can be read against load
  • Boost target vs actual boost (or absolute manifold pressure), full pull
  • Wastegate duty cycle, and actual wastegate position where the platform exposes it
  • Ignition timing per cylinder and any knock / ignition-correction channel
  • Intake air temperature and coolant temperature
  • High-pressure fuel rail pressure, target vs actual — the defining limit on ethanol
  • Injector duty or pulse width where your logging software exposes it
  • Measured ethanol content for the tank the log was taken on

Reading what comes back: the BMW data logging guide goes channel by channel, and the wastegate duty cycle guide covers boost control.

Flash, log, review, revise.

The first file is conservative. Your logs decide every revision after it, and log-based revisions are included in the calibration price.

The process
  1. 01

    Submit your build

    Chassis, engine, full mod list and target fuel. This defines a safe calibration starting point before any file is touched.

  2. 02

    Receive a base map

    A conservative calibration matched to your hardware and fuel, flashed with your own software at home.

  3. 03

    Log and send back

    Full-throttle pulls and part-throttle data captured on our channel list, then sent over for review.

  4. 04

    Review and revise

    We read the logs, adjust the calibration and repeat until the car is running clean and on target.

B58 E30 Blend questions.

More answers
How do I mix E30 for a BMW?
Blend E85 with pump gasoline by volume — roughly 30 parts E85 to 70 parts pump fuel gets you close, but pump E85 is not actually 85% ethanol year-round and varies by season and region. Test the finished tank with an ethanol content tester and tell us the measured number. A blend you measured beats a blend you calculated.
Is E30 safe on a stock B58 fuel system?
On a stock-turbo B58 at sensible targets, yes — that is the configuration this calibration is written for. The limit is fuel delivery, not the fuel itself: as boost and power rise, the high-pressure pump runs out of headroom before anything else does. We watch rail pressure in your logs and cap targets at what your car actually holds.
Should I run E30 or E85 on a B58?
E30 is the practical choice on a stock-turbo car: most of the knock resistance, far less fuel-system demand, and a blend you can still mix at an ordinary station. Full E85 only pays for itself once the turbo and fuel system can use it. There is a fuller comparison in our E30 vs E85 guide.
What happens if I run out of E30 and fill up with pump gas?
Do not drive the ethanol map on pump fuel. That is what map switching is for — a second, pump-fuel calibration you can flash or switch to. Tell us up front if you want both and we will build the pair.

Where this sits in the B58 range.

All tunes

Built around your B58.

Chassis, model year, hardware and the fuel you actually run is all we need. If you already have logs, include them: it usually saves a revision round.

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