12 Volt Bosch Coil

12-Volt Bosch Blue Ignition Coil - The Gold Standard for VW Performance

Ensure your air-cooled engine starts quickly and idles smoothly with the legendary 12-Volt Bosch Blue Ignition Coil from Appletree Auto. Widely recognized as the most reliable ignition coil in the Volkswagen community, the "Blue Coil" is famous for its internal resistor design and consistent high-voltage output. Unlike standard coils that may require an external ballast resistor, this self-contained unit simplifies your engine bay wiring while providing a hotter spark than stock factory units, resulting in better combustion and improved throttle response.

The Bosch Blue Coil is engineered to handle the high-heat environment of the air-cooled engine bay, featuring a durable metal housing and high-quality internal windings. It is the preferred choice for both daily drivers and off-roaders who demand "set-it-and-forget-it" dependability. Whether you are running a traditional points-and-condenser setup or have upgraded to a modern electronic ignition, this genuine Bosch coil from Appletree Auto provides the electrical punch your Beetle, Bus, or Sand Rail needs to perform at its best.

Product Fitment & Compatibility

This 12V coil is designed for all Volkswagen Type 1, Type 2, and Type 3 engines equipped with a 12-volt electrical system. It is a universal upgrade for both stock and performance air-cooled builds.

• Volkswagen Beetle (Standard): 1967 - 1977 (Factory 12V models and 6V-to-12V conversions)
• Volkswagen Super Beetle: 1971 - 1979
• Volkswagen Karmann Ghia: 1967 - 1974
• Volkswagen Bus / Transporter (Type 2): 1967 - 1979
• Volkswagen Thing (Type 181): 1973 - 1974
• Custom Sand Rails & Dune Buggies: All 12V air-cooled configurations

Tech Tips & Installation Advice

• Internal Resistor Advantage: The Bosch Blue Coil features a built-in internal resistor (typically 3.0 to 3.4 ohms). This means you do not need an external ceramic ballast resistor. If your vehicle currently has an external resistor, you should bypass it for the best performance.
• Identify Your Terminals: Proper wiring is critical. Connect your 12V ignition power wire to the positive terminal (marked "+" or "15"). Connect the wire leading to the distributor (points or electronic module) to the negative terminal (marked "-" or "1"). Reversing these will result in a weak spark and potential damage to the coil.
• Electronic Ignition Compatibility: This coil is the perfect companion for Pertronix Ignitor or other magnetic-pickup ignition modules. The internal resistance provides the protection these modules need to prevent overheating, unlike "low-resistance" racing coils which can burn out street-driven modules.
• Keep it Clean: Ensure the mounting bracket has a solid, clean contact with the fan shroud or engine case. While the coil is internally grounded, a secure bracket prevents vibration from damaging the internal windings over time.
• Spark Plug Gap: Because the Bosch Blue Coil provides a stronger spark than a stock 12V coil, some tuners choose to slightly increase their spark plug gap (to roughly .028" - .030") to take full advantage of the increased voltage. However, for most stock engines, the factory .025" gap remains a reliable standard.