BMW B58 Tuning
The B58 is our home platform. We're building one toward 1,500 horsepower, and we run B58 Racing, a parts brand built around this engine. If you have a B58, you're in the right place.
Cars with the B58
The B58 is BMW's 3.0L single-turbo inline-six, in Gen 1 and updated Gen 2 (TU) versions. It's strong from the factory and responds extremely well to tuning.
- 3 / 4 Series
- 340i · 440i · M340i · M440i
- 2 Series
- M240i
- 5 Series
- 540i
- X Models
- X3 M40i · X4 M40i · X5 / X6 / X7 40i
- Z4
- Z4 M40i
- Toyota
- GR Supra 3.0
Know which B58 you have
Gen 1 cars run from roughly 2015 to 2019. The Gen 2 (TU) engine that followed changed a lot under the skin.
- Fuel system: Gen 2 runs much higher injection pressure, with new injectors and a bigger fuel pump.
- Turbo and head: Gen 2 comes in two layouts, one for cars like the M340i and Supra and one for cars like the 540i. Turbos and tunes differ.
- Newer cars: some 2022+ engines add factory port injection.
We confirm your engine and software from the VIN before we quote.
The GR Supra 3.0
The Supra 3.0 uses the same B58 as the M340i, with the same strengths and the same limits.
Most published B58 dyno results come from Supras and M340i cars. A 540i or X5 40i starts lower from the factory, so expect a little less from the same stage.
B58 build paths
Typical wheel horsepower reported for Gen 2 cars. Stock is roughly 350-370 whp on cars like the M340i and Supra, and 320-340 whp on cars like the 540i. Gen 1 cars usually land lower. Dynos differ by 10% or more, and results depend on the car, fuel and parts.
Tune only
400-450 whpon 93 octane
Software on a stock car. Big gains for the money.
- Stock car
- 93 octane or E-blends
- Health check and baseline logs first
Bolt-ons
420-450 whpon 93 octane · 450-490 whp on E30 · 480-510 whp on E40
On a B58, ethanol adds more than the parts alone.
- Downpipe, intake and inlet
- Upgraded intercooler
- Charge pipe
Built B58
700-900+ whpbig single turbo on E85 with full fuel and transmission upgrades
The stock turbo tops out around 550 whp on E85. Past that, it's a full build.
- Hybrid or big single turbo
- Port injection and fueling
- Transmission and cooling upgrades
Pump gas, ethanol and flex fuel
Stage 1 is commonly set up for 93 octane.
Ethanol adds power and knock margin, which matters in a Texas summer. Stock fueling supports a partial blend, not full E85, and Gen 1 cars run out sooner. For more, we plan fuel upgrades and tune for the blend you'll really run.
Ethanol can dilute the oil, so E-blend cars need shorter oil change intervals.
A healthy engine first
Every job starts with a health check and baseline logs, and every car gets a digital inspection with photos and video.
- Leaks and cooling: we check for leaks and watch oil temperature on hot days.
- Ignition: tuned cars usually want a colder plug with a tighter gap.
- Charge pipe: the factory plastic pipe is known to crack under more boost.
- Knock: sustained torque and knock hurt B58s, not peak horsepower.
Anything that needs fixing first goes through our maintenance and repair service.
The ZF 8HP and big power
B58 cars with an automatic use a version of the ZF 8-speed. It's tougher than its paper rating, but stock units are commonly reported to start slipping around 650-700 whp.
A transmission calibration can raise clamping pressure and torque limits. For big-turbo cars we plan an upgraded transmission as part of the build, not after something fails.
The 1,500 HP B58
Our shop car is a B58 headed toward 1,500 horsepower. Parts and calibration strategies get tested there first.
The point is to find where the limits really are, so customer cars stay far from them. Follow along on our racing and projects page.
How a B58 tune works with us
Inspect and log
We confirm your engine from the VIN, inspect the car and record baseline logs.
Tune for your setup
Boost, timing and fueling are set for your parts, your fuel and Texas heat. Your original software is saved where the platform allows.
Verify and refine
We log again after the tune and revise until it's right. Not local? We can tune remotely with log reviews.
More on our ECU tuning. Planning parts too? Our performance upgrades team sources, installs and tunes everything as one package. M car? See our S58 and S55 guides.
B58 FAQ
Gen 1 or Gen 2 B58: does it matter?
Yes. The Gen 2 (TU) engine has different internals and software, so tunes and some parts differ. We'll confirm which one you have from your VIN.
What's the first mod for a B58?
A tune. Most B58s gain a lot from software alone, and it sets you up for the rest of the build.
Do you tune the GR Supra?
Yes. The Supra 3.0 uses the B58, so it gets the same tuning and parts expertise as our BMWs.
What fuel should I run?
Stage 1 tunes are commonly set up for 93 octane. Ethanol blends add power and knock margin, but the stock fuel system can't support full E85. We'll tune for the fuel you can actually buy.
How much power can a stock B58 take?
It depends on generation, fuel and use. The stock turbo is commonly reported to top out around 550 whp on E85. Beyond that, fuel, transmission and internals all need a plan.
Will my transmission hold the power?
The stock ZF 8-speed is commonly run at stage 1 and stage 2. For big-turbo power we plan transmission upgrades as part of the build.
Where can I buy B58 parts?
Our sister brand B58 Racing sells B58 performance and cosmetic parts that ship from Texas. We can install them too.
Tuning availability and results depend on model year, software and hardware. Modifying engine software can affect warranty coverage on related parts, and some modifications are intended for off-road or competition use only. We'll confirm what's possible for your exact car before any work.