N55 PWG vs EWG: How to Tell Which Engine You Have
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Short answer: early N55 engines use a pneumatic wastegate (PWG) controlled by vacuum, and later N55 engines use an electric wastegate (EWG) with an electric actuator on the turbo. Look at the turbo: a vacuum canister with a rubber line means PWG, an electric actuator with a wiring connector means EWG.
What changed
The N55 is BMW's 3.0-liter single-turbo inline six, used across the 1, 3, 4, 5, 6 and 7 Series and the X3, X4, X5 and X6. Partway through production BMW switched the turbo's wastegate control from vacuum to an electric actuator. The changeover timing varies by model, so the turbo itself is the most reliable check.
How to tell which you have
- Look at the turbo. PWG: round vacuum canister with a hose. EWG: rectangular electric actuator with a plug.
- Check the vacuum lines. PWG engines have vacuum lines and a converter valve running to the wastegate. EWG engines do not need that wastegate vacuum circuit.
- Use your VIN. A parts catalog lookup shows the correct turbo and engine part numbers for your car.
Why it matters when buying
- The turbo, related vacuum and wiring parts and the engine software differ between versions.
- Swapping one version into a car built for the other usually means changing wiring, vacuum parts and DME software, so matching versions is the simplest path.
- Drivetrain also matters: rear-wheel drive and xDrive engines can differ in oil pan and related parts.
Shop N55 engines
We list N55 engines by version: N55 PWG engines and N55 EWG engines. Listings include mileage and drivetrain, and many include a running video. Also see used BMW turbochargers and our used BMW engine buying checklist.
Need help confirming fit?
Call or text our sales team at 954-882-3346 with your VIN and the part you need, and we will help confirm fit before you order. Every used part we sell carries a 30-day warranty.