DOC Race B58 Gen2 & B48 Top Mount Turbo Kit – BMW G-Chassis / Toyota GR Supra

OVERVIEW

DOC Race top-mount turbo kits for the G-chassis B58 Gen 2 (M340i / M240i), the G-chassis B48, and the 6-port GR Supra Sportsman Series. Each replaces the factory turbo with a single large-frame Precision turbo on a purpose-built top-mount manifold.

The B58 Gen 2 and B48 options are priced as kits less turbo — you supply your own Precision turbo. The Supra Sportsman Series option includes the turbocharger.

SPECS

• B58 Gen 2 option: kit less turbo, 1.25 Schedule 40 runner, stainless tubular manifold with 1.90" OD runners
• B48 option: kit less turbo
• Supra Sportsman Series option: 6-port B58, Precision Sportsman turbo included (6870 / 6875 / 7175 / 7475)
• 2 x Turbosmart 45mm wastegates with external dump tubes; 3.5" stainless downpipe
• Precision (PTE) turbochargers only
• Built to order; approximately 4 weeks lead time
• Turbo-included versions of the B58 Gen 2 and B48 kits are available by special order — Contact Speed Logic for pricing

PARTS INCLUDED

• Stainless tubular T4 twin-scroll manifold
• 2 x Turbosmart 45mm wastegates and 2 x dump tubes
• 3.5" stainless downpipe
• 2 x charge pipes (turbo to throttle body), silicone couplers and clamps
• Stainless oil drain, oil feed and coolant bypass line kits
• T4 gasket, turbo studs and nuts, exhaust V-band clamp
• 4" turbo screen and heat shield
• 1/4" nylon tubing and fittings for wastegate routing
• Valve cover vent filter and 2 x 3/4" boost caps
• Precision turbocharger (Supra Sportsman Series option only)

TECH RESOURCES

Required Additional Parts

• Precision turbocharger (required for B58 Gen 2 and B48 options) — not included in those prices.
• Tuning (required): B58 — Bootmod3 B58 Tune, MHD Super License – B58, JB4 Tuner – B58 Gen1 & Gen2; B48 — Bootmod3 B46/B48 Tune or JB4 Tuner – B48; Supra — Bootmod3 GR Supra Tune.
• ECU unlock for locked B58 DMEs: Speed Logic ECU Unlock Service.
• Supporting fueling sized for your power target, e.g. JB4 Fuel Pressure Upgrade Kit.

Installation

• DOC Race kit video: B58 top mount turbo kit.
• Wastegate vacuum lines must be routed away from exhaust heat; melted lines can cause over- or under-boost.
• DOC Race does not list specific B48 models — confirm your model with Speed Logic before ordering.
• DOC Race does not publish an installation manual for these kits. Contact Speed Logic for install support.

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