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Build log from our own B58s, and buying guides from what we've learned.
Buying guides
Best A90 Supra Mods, In the Order to Do Them (GR Supra 3.0)
Tune it first. On a GR Supra 3.0, a flash tune or a JB4 is the biggest gain per dollar. Next, add a downpipe and a Stage 2 map, and a better heat exchanger so the car stays strong on hot days. After that comes fuel: flex
Read Buying guideB58 Charge Pipe Install: Gen 1 F-Chassis vs Gen 2 G-Chassis and the GR Supra
The B58 charge pipe runs from the turbo outlet to the throttle body. Swapping it is a top-side job on most cars: pull the intake, unclip the pipe from the turbo, unbolt it from the throttle body, move the sensors and O-r
Read Buying guideB58 Common Problems by Generation (Gen 1, Gen 2 and 2025+) and the Parts That Fix Them
The B58 is one of BMW's most reliable modern engines, and most of its problems are leaks, not failures. The ones that come up again and again are the oil filter housing gasket, coolant leaks (water pump, expansion tank,
Read Buying guideB58 Downpipe Install Guide: Gen 1 F-Chassis, Gen 2 G-Chassis and the GR Supra
A B58 downpipe swap is a bolt-on job. You undo one V-band clamp at the turbo, the joint at the mid pipe and a support bracket, move the two oxygen sensors over, and fit the new pipe with a fresh turbo gasket. Plan on 2 t
Read Buying guideB58 Fueling Explained: HPFP, LPFP, Port Injection, Flex Fuel and E85
The B58 fuel system has two pumps. The low-pressure pump (LPFP) in the tank feeds the high-pressure pump (HPFP) on the engine, which feeds the direct injectors. On a tuned car, the HPFP is usually the first wall, and eth
Read Buying guideB58 Gen 1 vs Gen 2: How to Tell Which You Have and Why It Matters
Gen 1 is the original B58 (engine code B58B30M0), found in F-chassis cars and early G-chassis cars like the 2017–2019 540i. Gen 2 is the 2018 "technical update" or B58TU (codes B58B30M1 and B58B30O1). It's in the G20 M34
Read Buying guideB58 Oil Filter Housing Gasket Replacement: Gen 1 F-Chassis, Gen 2 G-Chassis and the GR Supra
The B58 oil filter housing bolts to the intake side of the block, near the back of the engine. It carries both oil and coolant, because the oil cooler (heat exchanger) is mounted on it. When its gaskets harden, you get o
Read Buying guideB58 Spark Plugs and Coils: Interval, Gap for Tuned Cars and a DIY Swap
Gen 1 B58s (2016 to 2019 F-chassis cars) take BMW plug 12120040551, and NGK's version of that plug is the 94201 (SILZKGR8B8S). Gen 2 B58TU cars, including the GR Supra, take BMW 12122455258 (also listed as 12125A4EF60),
Read Buying guideBest B58 Mods, In the Order to Do Them
Start with a tune. It is the biggest gain per dollar on any B58. Then add a downpipe and a Stage 2 map, then an upgraded high-pressure fuel pump (HPFP) and an ethanol blend. Only after that should you think about a bigge
Read Buying guidebootmod3 vs MHD vs JB4 for the B58: Which Should You Buy?
For most B58 owners who plan to keep modding, buy a flash tune. bootmod3 is the polished, cloud-based choice with a big custom-tuner network. MHD costs less to start and keeps maps and logs on your phone. The JB4 is a pi
Read Buying guideBest M340i / M440i / M240i Intake, and How to Install It
On a G20 M340i, G22 M440i or G42 M240i, an intake is mostly about sound. You hear the turbo spool and the blow-off. Power gains are small, and the makers' own claims run from about 9 to 19 hp. For the cheapest change, us
Read Buying guideBMW G20 M340i / G22 M440i Mods Guide: The Best B58 Upgrades, In Order
Tune it first. On a G20 M340i or G22 M440i, a tune is the biggest gain for the money. Then add a downpipe and a Stage 2 map, an aluminum charge pipe, and better cooling. Fuel upgrades and ethanol come after that. Suspens
Read Buying guideS58 Charge Pipe Install: Y-Pipe and Hot Side for the M2, M3, M4, X3 M and X4 M
The S58's factory charge pipe is a plastic Y-pipe. It joins a pipe from each turbo and feeds the throttle body. A full Y-pipe swap is a big job. Following Mishimoto's G80 instructions, you take off the underbody trays, d
Read Buying guideS58 Downpipe Install: G80 M3, G82 M4, G87 M2 and F97/F98 X3 M/X4 M
The S58 has two turbos, so you're swapping two downpipes, two turbo gaskets and four oxygen sensors. The job is done mostly from underneath. You drop the underbody trays and the center brace, support and unbolt the mid p
Read Buying guideBMW S58 Mods Guide: M2, M3, M4, X3 M and X4 M Upgrades in Order
On an S58, start with a tune and cooling. These cars make a lot of power stock, and heat is what holds them back on hot days and back-to-back pulls. Next come downpipes and a tune built for them, then fuel: an ethanol an
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