WARMING THE ENGINE…
The B58 is BMW's modern single-turbo 3.0-litre straight-six, fitted from 2015 onwards across the 40i lineup — the 340i and 440i, the Z4 M40i, and the G20/G30 generation cars. One twin-scroll turbo does the work two used to: the architecture spools early, holds hard, and responds to calibration like the N54's successor should — more headroom from the factory, and a tune that makes the most of what's there without chasing numbers.
Charge cooling on the B58 is nothing like the N54/N55 era, and the parts list follows the architecture. There is no front-mount intercooler and no charge pipe spanning to the chassis: the charge cooler is a water-to-air core built into the intake manifold, fed by a low-temperature coolant circuit with its own front heat exchanger. All the boost plumbing lives on the engine — one less leak path to chase as the car ages. So the real B58 hardware story is a manifold upgrade with port injection for big builds, a bigger heat exchanger and healthy pump flow for the circuit, and a downpipe. That is what our shelf carries — no fiction about front mounts.
Every B58 tune is per-VIN, flashed by you, refined from your datalog — one revision included. The configurator gates your boost target to the safe envelope for the platform and the fuel genuinely in the tank; the log, not the marketing, gets the final word.
Every stage is per-VIN, flashed by you, with one revision included. Boost targets live inside the safe envelope for your fuel — the datalog gets the final word.
| Stage | Boost target | Fuel | Assumes |
|---|---|---|---|
| B58 Stage 1 | 16–18 psi | 93 pump / E30 | Stock hardware — the calibration the 40i left the factory wanting. |
| B58 Stage 2 | 19–22 psi | 93 pump / E30–E50 | Downpipe + charge-cooling support — the flow and coolant temperatures to hold a firmer target. |
| B58 Stage 3 | 22–28 psi | E50–E85 | Upgraded turbo, ethanol and port injection — built from your logs, hardware leads. |
Water-to-air in the manifold: a charge-cooler manifold with port injection for big builds, a bigger front heat exchanger for the low-temp circuit, and the pump that feeds it.
A sealed box feeds cool air; the high-flow catted downpipe opens the exhaust side with no CEL at stage 1.
Colder plugs keep ethanol ignition happy; the flex-fuel sensor lets the calibration read the real blend.
Programmable boost control with map slots — including a valet slot you'll actually use.
Stage 1 is: stock turbo and downpipe, bolt-ons okay. Your boost target sits inside the safe envelope for the B58 and your fuel — 14–20 psi on 93 pump, up to 22–30 psi on E85 — and the first datalog decides whether the refinement pulls anything back. One revision is included.
No — it can't take one, because the B58 doesn't use air-to-air charge cooling at all. The charge cooler is a water-to-air core integrated into the intake manifold, with a front heat exchanger and coolant circuit carrying the heat away. If charge temps are your concern, the real upgrades are a larger heat exchanger, healthy pump flow, and at the top end a charge-cooler manifold upgrade. A front-mount intercooler belongs to the N54/N55 era, and we don't sell one for the B58.
Two things at once. A larger water-to-air core in the manifold drops charge temps where the air actually enters the engine, and integrated port-injection rails add fuel above what the direct-injection system can safely supply on high-ethanol builds — the supporting cast a big-turbo, E50+ car needs. Ours is sourced to order and specced with your build.
Stage 1 assumes a stock car (16–18 psi, 93/E30). Stage 2 assumes a downpipe and charge-cooling support behind the target (19–22 psi, up to E50). Stage 3 assumes an upgraded turbo on ethanol (22–28 psi, E50–E85) — usually with port injection — and is calibrated from your logs of that hardware in your car.
The single-turbo 3.0-litre B58 has been fitted from 2015 onwards in the 40i lineup — G20 3-Series, G30 5-Series, G32 6-Series GT, F2X 2/3/4-Series applications and the Z4. Our manifold, heat exchanger, downpipe and intake fitments cover these chassis.