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B58 Racing

Buying guide · Gleb Blekher

Best B58 Mods, In the Order to Do Them

Short answer: 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 bigger turbo, and a built motor comes last. Cooling, ignition and fresh fluids should keep pace with each step.

Parts and tunes in this guide are for off-road / competition use only. Not legal for use on public roads in the United States, including California.

I'm Gleb Blekher. I run B58 Racing out of Dallas, TX, and I've spent 15+ years around motorsports. I've built two B58 cars myself, an M240i and a 540i. This is the order I'd follow again, and the order I tell customers to follow.

Before you buy anything: two quick checks

  1. Know your generation. Gen 1 and Gen 2 B58s use different charge pipes, fuel pumps, injectors and turbos. Chassis code alone can fool you. Read our B58 Gen 1 vs Gen 2 guide first.
  2. Plan your tune. Every step below runs through your tune. Make sure the one you pick supports your car and your DME before you buy hardware around it.

The B58 mod order at a glance

StepMain partsWhat you need firstHonest takeShop
Stage 1Flash tune or JB4, fresh plugs, inlet pipe, filterNothingBest value on the carTuning, intakes
Stage 2Downpipe + Stage 2 map, transmission tuneStage 1 tuneBig jump in midrange; louderDownpipes
Stage 2+ / E-blendUpgraded HPFP, flex fuel kit, LPFP if neededStage 2Where the stock fuel system runs outFueling
Big turboHybrid or single turbo, port injection, sensorsFull fuel system, E-blendExpensive; custom tune onlyTurbos
Built motorPistons, rods, studs, head gasket, camsBig turbo planOnly when your power goal needs itEngine
Every stageCooling, charge pipe, plugs, coils, fluids, tiresNothingCheap insuranceCooling, Charge pipes

Stage 1: tune first, then the small stuff

The tune

The tune is the mod. Everything else supports it. Most owners go one of two ways:

  • Flash tune. Rewrites the DME software with an off-the-shelf (OTS) map, or a custom map from a tuner. OTS maps are sold by stage, so you can move up as you add parts. Shop tuning.
  • Piggyback, like the Burger Motorsports JB4. It sits between the sensors and the DME. It does not rewrite the factory software and can be unplugged. Burger Motorsports claims up to 120 whp and 120 lb-ft at the wheels on a stock B58 on pump gas. That's a maker figure, not our dyno number.

One catch: many B58 DMEs need a bench unlock before any flash tool can write to them. DMEs built after mid-2020 are the usual suspects. Check before you buy.

Spark plugs and coils

Fresh plugs before the first flash is common advice, and we agree. Gen 1 cars use the NGK Laser Iridium 94201 set. Gen 2 cars and the Supra use NGK 96206. If a coil is weak, Eldor is an OE supplier for B58 coils.

Inlet pipe and air filter

Here's the honest version. On a stock turbo, intakes are mostly about sound and turbo noise. They are not where the power is.

  • B58 Racing Silicone Inlet Pipe (resonator delete) — $34.95, fits Gen 1 and Gen 2. It replaces the factory resonator section with a smooth silicone pipe. You'll hear more turbo. See the inlet pipe.
  • ProRam stock-box B58 air filter — a drop-in for the factory airbox.
  • Full intakes from Burger Motorsports, aFe, Dinan and Eventuri are in our intakes category. Eventuri carbon is mostly a looks-and-sound buy. Be honest with yourself about that.

G30 owners: the G30 has extra air baffling. In our experience the silicone inlet pipe can trigger an air-leak code on a G30 unless your tuner codes it out. Plan for that.

Stage 2: downpipe and a Stage 2 map

A downpipe frees up the exhaust right after the turbo. It's the hardware that Stage 2 maps are built around, and it needs a matching tune.

Options we'd look at:

Expect a louder car and more drone on the highway. All of these are off-road / competition parts. Browse downpipes.

Transmission tune (ZF 8-speed)

Most B58 cars use the ZF 8HP automatic. An xHP Flashtool license tunes the transmission. Stage 1 removes the factory torque limiters so your engine tune can use its real torque values. Higher stages speed up shifts. On a tuned automatic, this is one of the best "feel" upgrades you can buy.

Stage 2+ and E-blend: the fuel system

On the stock turbo, fuel is the next wall. The Gen 1 B58 HPFP is a 200-bar system. Gen 2 (B58TU) runs a 350-bar system. One tuning guide estimates the stock Gen 1 pump runs out around 450 whp on 93 octane. Stage 2+ maps generally require an upgraded pump.

HPFP

  • Gen 1: Spool Performance FX-200 or FX-350. Both our cars run a Dorch Engineering Stage 2 pump, which also works well.
  • Gen 2: Spool Performance FX-350 for the BMW Gen 2 B58 and the GR Supra, or the Dorch Engineering Gen 2 DS25 (350 bar). A pump this big needs bigger injectors to use all of it: Spool's IFX350 Stage 1 injectors are the usual pairing.

Flex fuel and E-blends

Ethanol adds knock resistance, and the tune turns that into timing and boost. A flex fuel kit reads ethanol content live, so you don't have to mix perfectly every fill. Spool's wireless ethanol analyzer kits plug in without cutting wires: Gen 1 B58, Gen 2 B58 and GR Supra. Your tuning platform may also sell its own kit.

Ethanol also loads up the low-pressure pump in the tank. Upgrade it at the same time:

Trade-off: ethanol isn't sold everywhere, and you burn more of it. If you can't buy E85 nearby, a pump-gas Stage 2 car is still very fast.

Shop fueling.

Big turbo

This is where costs climb fast. A turbo upgrade needs a custom tune, an E-blend, and a fuel system to match.

What usually comes with it:

Turbos are generation- and head-specific. A Gen 2 "2-port" turbo won't fit a 6-port engine. Check before you buy.

Built motor

The B58 bottom end has a strong reputation, so most street cars never need a build. You build the engine when your power target goes past what you and your tuner trust on stock internals.

Supporting and reliability mods (do these as you go)

  • Cooling: A CSF heat exchanger (F-series, G-series and Supra) helps the intercooler loop on hot days (see our B58 intercooler install guide). CSF auxiliary radiators (F-series, G-series and Supra) help on track. In a Texas summer, this matters. Shop cooling.
  • Charge pipe: Honest take: one B58 guide reports very few factory charge pipe failures, mostly on upgraded turbos. We see an aluminum pipe as insurance at higher boost. Good options: the Spool charge pipe kit (Gen 1 and Gen 2), FTP Gen 1, MMX and do88 for F-series cars. Gen 1 and Gen 2 pipes do not interchange. Shop charge pipes.
  • Oil: a catch can like the VTT B58 catch can, and shorter oil intervals on tuned cars. We carry service kits and oils from Motul, Liqui Moly and Red Line.
  • Fluids: Red Line 75W85 diff fluid and, on xDrive cars, transfer case fluid.
  • Tires: Power is useless without grip. Michelin Pilot Sport 4S for the street; Mickey Thompson ET Street R for the strip.
  • Mounts: Insert kits from Bimmerworld and Powerflex firm up the drivetrain. Expect more vibration.

Not sure what fits together? Shop by your car or send us your VIN and we'll check every part against it before you order.

From our builds

BMW M240ix (F22, Gen 1, xDrive), 3,340 lb. Downpipe, Dorch Engineering Stage 2 HPFP, and a custom tune by Sameh Yehia. Result: low-8-second 60–130 mph on the stock turbo.

2017 BMW 540i (G30, Gen 1, RWD), about 4,000 lb with a full tank. Full luxury interior kept. Downpipe, a tune on E50, Dorch Stage 2 HPFP, xHP transmission tune. Result: low-9-second 60–130 on the stock turbo, even though it spun on the hit. On a heavy RWD car, plan for traction. It runs Supra wheels on Michelin Pilot Sport 4S and a black grille.

Neither car needed a big turbo to be seriously fast. Tune, downpipe, fuel and ethanol did the work.

FAQ

What are the best B58 performance parts to buy first?

In order: a tune, then a downpipe, then an upgraded HPFP and ethanol analyzer. Add cooling and a charge pipe along the way. That covers most of what a stock-turbo B58 can do.

Are Gen 1 and Gen 2 B58 parts the same?

Often not. Charge pipes, fuel pumps, injectors, turbos and many downpipes are generation-specific. Every part on our site lists the cars it fits, and we'll check your VIN if you're not sure.

What is the best first mod for a B58?

A tune. A flash tune, or a piggyback like the JB4, gives the largest gain for the money. Everything else builds on it.

Do I need a downpipe for Stage 2?

Yes. Stage 2 maps are built around an aftermarket downpipe. Running a Stage 2 map without one is not what the map was designed for.

When do I need an upgraded HPFP?

When you go past Stage 2 on pump gas, or start running higher ethanol blends. Stage 2+ maps generally require an upgraded pump.

Is an intake worth it on a B58?

On a stock turbo, mostly for sound. Our silicone inlet pipe is a cheap way to get that sound. Save the bigger money for the tune and downpipe.

Should I upgrade the charge pipe?

At stock-turbo boost it's optional. At big-turbo boost, or if you want peace of mind, an aluminum pipe is cheap insurance.

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