Complete B58 E9x Swap Parts List: Every Part You Need (2026)
Planning a B58 swap into your E9x? The single biggest mistake builders make is starting without a complete parts list — leading to mid-build delays, wrong parts, and budget blowouts. This is the definitive checklist organized by build phase.
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What Engine Do I Need?
| Donor Vehicle | Engine Code | HP (Stock) | Typical Price | Best For |
|---|---|---|---|---|
| 2016-2018 340i (F30) | B58B30M0 | 335 hp | $3,000–$4,500 | Best value |
| 2019+ 330i (G20) | B48B20M1 | 255 hp | $2,200–$3,500 | Budget builds |
| 2019+ M340i (G20) | B58B30M1 | 382 hp | $4,500–$6,000 | Max power |
| 2020+ Supra (A90) | B58B30M1 | 382 hp | $5,000–$7,000 | Premium builds |
Pro tip: Always buy the engine with its complete wiring harness and DME. A standalone engine without electronics will cost you $800–$1,500 extra in custom wiring.
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Phase 1: Engine & Transmission
Core Components
- B58 engine assembly — Complete long block with turbo, intake manifold, and accessories. OEM Part: 11002473030 (B58B30M0). *$3,000–$6,000*
- ZF 8HP45 transmission — From 2016+ 340i F30. Part: 24009851050. *$1,200–$2,500*
- Transmission mechatronics — Must match your 8HP variant. *$400–$800*
- Engine wiring harness — Full OEM harness from donor vehicle. *Included with engine or $300–$500 separate*
- DME (ECU) — Must be matched/virgin or coded. MEVD17.2.x for B58. *Included or $400–$800*
- Flexplate/flywheel — B58-specific. Part: 11222457818. *$80–$150*
- Torque converter — Stock 8HP45 converter or upgraded unit. *$200–$600*
Estimated Phase 1 Total: $5,280–$10,850
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Phase 2: Cooling System
Required Parts
- Radiator — E9x 335i OEM radiator works (17117534914) or Mishimoto upgrade. *$150–$400*
- Electric water pump — B58-compatible auxiliary pump. *$80–$200*
- Thermostat housing — B58-specific (11537644811). *$60–$120*
- Coolant hoses — Custom silicone kit or OEM from donor. *$100–$300*
- Expansion tank — E9x OEM (17137552546). *$30–$60*
- Hose clamps — Stainless spring clamps, 15-20 pieces. *$20–$40*
Estimated Phase 2 Total: $440–$1,120
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Phase 3: Motor Mounts & Subframe
Required Parts
- Custom motor mount adapters — Fabricated steel or polyurethane adapters to mate B58 to E9x subframe. *$200–$600*
- Transmission mount — Modified or custom for 8HP in E9x tunnel. *$100–$300*
- Subframe reinforcement plates — Welded-in strengthening for increased torque. *$50–$150*
- Hardware kit — Grade 10.9 bolts, M10/M12 for mount plates. *$30–$60*
Estimated Phase 3 Total: $380–$1,110
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Phase 4: Fuel System
Required Parts
- High-pressure fuel pump (HPFP) — B58 OEM (13518631642) or upgraded unit. *$200–$500*
- Fuel injectors — B58 OEM Bosch DIVA piezo injectors (x6). *$300–$600 for set*
- Fuel lines — E9x to B58 adapter lines, AN-6 braided stainless. *$80–$200*
- Fuel pressure regulator — If running standalone. *$60–$120*
- Low-pressure fuel pump — E9x in-tank pump works for stock power. Upgrade for 500+ hp. *$0–$300*
Estimated Phase 4 Total: $640–$1,720
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Phase 5: Exhaust System
Required Parts
- Downpipe — B58 catless or catted, 3-inch minimum. *$200–$600*
- Midpipe — Custom 3" stainless connecting downpipe to E9x exhaust. *$150–$400*
- Exhaust gaskets — Turbo-to-downpipe and midpipe flanges. *$20–$50*
- V-band clamps — 3" stainless V-bands (2-3 needed). *$30–$60*
- O2 sensor bungs — Weld-in bungs for pre/post-cat sensors. *$15–$30*
- Cat-back (optional) — Full 3" cat-back for maximum flow. *$300–$800*
Estimated Phase 5 Total: $715–$1,940
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Phase 6: Wiring & Electronics
Required Parts
- Custom engine harness — Splice map connecting B58 DME to E9x JBE via CAN-Bus. *$400–$1,200 (DIY vs pre-made)*
- CANTCU controller — For standalone 8HP transmission control. *$300–$500*
- Accelerator pedal — 6-pin drive-by-wire unit wired to B58 DME. *$50–$100*
- CAN-Bus termination resistors — 120Ω (2 needed). *$5–$10*
- Immobilizer defeat — Coding or hardware bypass. *$0–$200*
- MHD or Bootmod3 license — For DME flashing. *$50–$100*
Estimated Phase 6 Total: $805–$2,110
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Complete Build Total
| Build Level | Estimated Cost |
|---|---|
| Budget Build (used parts, DIY mounts, stock tune) | $6,700–$9,000 |
| Mid-Range Build (quality used, polyurethane mounts, Stage 1 tune) | $9,000–$12,500 |
| Premium Build (low-mile donor, CNC mounts, full exhaust, Stage 2) | $12,500–$18,750 |
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Where to Source Parts
| Source | Best For | Notes |
|---|---|---|
| Facebook Marketplace / OfferUp | Donor engines, transmissions | Inspect in person. Get VIN for DME matching |
| Car-Part.com | Junkyard engine/trans search | Network of 4,000+ junkyards |
| FCP Euro | OEM replacement parts | Lifetime warranty on everything |
| Turner Motorsport | Performance upgrades | E9x specialists |
| ECS Tuning | Hardware, gaskets, cooling | Fast shipping, good prices |
| Kies Motorsport | Downpipes, intakes | B58-specific parts |
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FAQ
Can I use a B58 from a wrecked car?
Yes — as long as the engine turns freely and has no coolant-in-oil contamination. Always do a compression test before purchase. A front-impact wreck is acceptable; a rear/side impact with no engine damage is ideal.
Do I need the complete donor car or just the engine?
At minimum, you need the engine, wiring harness, DME, and transmission with mechatronics. The complete donor car gives you sensors, brackets, and accessories that are expensive to buy separately.
What about emissions and registration?
This varies by state. In most states, you can register a swapped vehicle if it passes emissions for the engine year (not the chassis year). California requires a BAR referee inspection. Research your local laws before starting.
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*Ready to plan your build? The B58 Swap Bible includes a complete phase-by-phase build checklist with torque specs and detailed instructions for every part on this list.*