Why 65,000-Volt Granatelli Coils Matter

Ford 4.6L & 5.4L 2V Spark Blowout

Your Ford 4.6L or 5.4L 2-valve engine can have the right fuel system, the right tune and plenty of airflow, but none of that matters if the ignition system cannot consistently light the mixture. This becomes especially important on supercharged, turbocharged and nitrous Ford Modular engines, where increased cylinder pressure makes the spark plug harder to fire.

One of the problems that can appear as power increases is commonly called spark blowout. Granatelli Motor Sports developed its Pro Series Xtreme 65,000-volt ignition coils for Ford 4.6L and 5.4L 2V applications where a stronger ignition system is needed under demanding conditions.

What Is Spark Blowout?

Spark blowout occurs when the ignition system struggles to create or maintain a consistent spark under high cylinder pressure. The higher the pressure inside the cylinder, the harder it becomes for the electrical energy to jump across the spark plug gap. That means an ignition system that works fine at idle or during normal cruising can begin struggling when the engine is under full load or boost.

What Does Spark Blowout Feel Like?

Spark blowout can sometimes feel like the engine suddenly hits a wall as boost or RPM increases. Possible symptoms can include:

• Misfire under heavy acceleration
• Engine breakup under boost
• Hesitation at high RPM
• Inconsistent power delivery
• Loss of power as boost increases
• Engine runs correctly at light throttle but poorly at wide-open throttle

These symptoms can have many possible causes, so the ignition system should be properly diagnosed rather than assuming every high-RPM misfire is caused by a weak coil.

Why Boost Makes Ignition More Difficult

A supercharger or turbocharger forces more air into the engine. More air allows the engine to burn more fuel and make more power, but it also increases the pressure inside the combustion chamber. The spark plug now has to fire through a more densely packed air/fuel mixture. As boost and cylinder pressure increase, the amount of available ignition energy becomes increasingly important.

Why Ford 2V Engines Benefit From Higher-Output Coils

Ford's 4.6L and 5.4L 2-valve Modular engines are popular platforms for performance upgrades. Many of these vehicles are now being modified with:

• Supercharger pulley upgrades
• Turbocharger systems
• Nitrous
• Camshafts
• Higher compression
• More aggressive tuning
• Higher RPM
• Increased boost pressure

As the engine combination becomes more aggressive, the ignition system must keep up.

Granatelli Pro Series Xtreme 65K Ford 2V Coils

The Granatelli Motor Sports 28-1697SC Pro Series Xtreme Coil Pack & Connector Kit is designed for compatible Ford 4.6L and 5.4L 2-valve Modular V8 engines. The coils produce up to 65,000 volts and are intended for demanding naturally aspirated, supercharged, turbocharged and nitrous applications.

What Comes in the 28-1697SC Kit?

• 8 Granatelli Pro Series Xtreme ignition coils
• Matching coil connector kit
• Up to 65,000 volts maximum output
• Zero-ohm resistance design
• Patent-protected isolator technology
• RFI and EMI suppression
• Direct OEM-style installation on compatible vehicles
• No external ignition amplifier required

65,000 Volts vs. Factory-Style Ignition Coils

The advantage of additional available voltage is not that the spark plug always consumes all 65,000 volts. The advantage is having additional ignition capability available when the operating conditions demand it. Under heavy load, boost or increased cylinder pressure, the voltage required to jump the plug gap can increase. A higher-output ignition coil gives the system additional headroom when those demands rise.

Why Granatelli Calls Them Pro Series Xtreme

Granatelli's Pro Series Xtreme coils are the highest-output coils in the Granatelli Ford 2V ignition lineup. They are specifically intended for combinations such as:

• Supercharged engines
• Turbocharged engines
• High-level nitrous applications
• High-compression engines
• High-horsepower street cars
• Drag racing vehicles

Granatelli Coil Dyno Results

Granatelli reports that the current 65,000-volt Pro Series Xtreme ignition coils can produce performance improvements when the original ignition system is limiting combustion.

Actual horsepower gains vary based on the condition of the existing ignition system, engine modifications, tune, boost level, spark plugs and overall engine combination.

Why Does a Boosted Engine Have More to Gain?

The coil does not create boost or increase airflow. Instead, a higher-output coil can help maintain reliable ignition when increased cylinder pressure makes the spark plug more difficult to fire. That means the benefit can become more noticeable on a combination where the existing ignition system is already approaching its limits. This helps explain why Granatelli reports greater potential gains on supercharged, turbocharged and nitrous combinations than on naturally aspirated applications.

Granatelli Coils on the 1999–2004 SVT Lightning

The 1999–2004 Ford F-150 SVT Lightning is one of the best examples of why ignition strength matters. Its 5.4L 2V V8 is supercharged from the factory. Lightning owners frequently increase performance with:

• Smaller supercharger pulleys
• More boost
• Ported superchargers
• Aftermarket superchargers
• Cold-air systems
• Exhaust upgrades
• Custom tuning
• Nitrous

Every time cylinder pressure increases, the ignition system has to work harder. The Granatelli 28-1697SC kit is specifically listed for the 1999–2004 5.4L supercharged SVT Lightning.

Granatelli Coils on the 1997–2004 Mustang GT

The Ford Mustang GT's 4.6L SOHC 2V engine remains one of the most popular Modular Ford platforms. Granatelli's 65K coils are compatible with 1997–2004 Mustang GT 4.6L 2V applications, including the 2001 Mustang Bullitt. They can be especially useful when the vehicle has been upgraded with:

• Vortech or centrifugal supercharger systems
• Roots-style or positive-displacement superchargers
• Single turbo systems
• Twin turbo systems
• Nitrous
• Performance camshafts
• Higher compression

Do I Need 65K Coils on a Stock 4.6L 2V?

Not every stock engine requires a 65,000-volt performance ignition coil. A healthy stock ignition system may already provide enough spark energy for a completely stock combination. However, Granatelli Pro Series Xtreme coils provide additional ignition capability for owners who:

• Plan future performance upgrades
• Are replacing aging ignition components
• Want a performance-oriented ignition system
• Have already increased horsepower
• Run forced induction or nitrous

Should I Replace All Eight Coils?

On a performance application, using a matched set of ignition coils provides consistent ignition capability across all eight cylinders. The Granatelli 28-1697SC is sold as a complete set of eight Pro Series Xtreme coils with the matching connector kit. Granatelli specifies that its high-output Pro Series Xtreme coils should be used as a complete set rather than mixing them with lower-output coil designs.

Should I Change the Spark Plugs Too?

Spark plugs and ignition coils work together. If you're diagnosing a misfire or upgrading a high-mileage ignition system, the condition and specification of the spark plugs should also be checked. Important considerations include:

• Spark plug condition
• Correct heat range
• Correct spark plug gap
• Boost level
• Fuel type
• Engine tune

A powerful ignition coil cannot compensate for an incorrect or damaged spark plug.

Does Spark Plug Gap Matter on a Boosted 2V?

Yes. As cylinder pressure increases, a large spark plug gap can become more difficult for the ignition system to fire. Some high-boost combinations require a tighter spark plug gap than a naturally aspirated engine. The correct gap depends on the specific engine, boost level, spark plug and tune.

Will Granatelli Coils Fix Every Misfire?

No. Ignition coils are only one possible source of a misfire. Other causes can include:

• Damaged spark plugs
• Incorrect spark plug gap
• Fuel injector problems
• Low fuel pressure
• Vacuum leaks
• Damaged wiring
• Connector problems
• Compression problems
• Incorrect engine calibration

The vehicle should be properly diagnosed before parts are replaced.

Do Granatelli 65K Coils Require an Ignition Box?

No external ignition amplifier is required for the compatible applications. The Granatelli 28-1697SC coils install as an OEM-style coil-on-plug upgrade while providing the increased output of the Pro Series Xtreme design.

Ford 2V Applications for Granatelli 28-1697SC

Compatible applications include select:

• 1997–2004 Ford Mustang GT 4.6L 2V
• 2001 Ford Mustang Bullitt 4.6L 2V
• 1999–2004 Ford F-150 SVT Lightning 5.4L Supercharged 2V
• Ford F-150 4.6L and 5.4L 2V
• Ford Expedition 4.6L and 5.4L 2V
• Ford Crown Victoria 4.6L 2V
• Ford Explorer 4.6L 2V
• Ford Excursion 5.4L 2V
• Lincoln Town Car 4.6L 2V
• Mercury Grand Marquis 4.6L 2V
• Mercury Mountaineer 4.6L 2V
• Select Ford E-Series 4.6L and 5.4L 2V applications

Ford used 2-valve, 3-valve and 4-valve Modular engines during overlapping model years, so always verify the engine configuration and original coil design before ordering.

65K Granatelli Coils: Key Specifications

Part Number	28-1697SC
Series	Pro Series Xtreme
Maximum Output	65,000 Volts
Quantity	8 Ignition Coils
Connector Kit	Included
Resistance	Zero Ohm
Engine Family	Compatible Ford 4.6L & 5.4L 2V Modular V8
Installation	Direct OEM-Style Replacement
Country of Origin	Made in USA

The Bottom Line

Making more horsepower means increasing the demands placed on the entire engine. The ignition system is no exception. As boost and cylinder pressure increase, maintaining a strong, consistent spark becomes increasingly important. The Granatelli Motor Sports 28-1697SC Pro Series Xtreme Ford 2V Coil Kit provides up to 65,000 volts and is designed specifically for performance 4.6L and 5.4L 2-valve Modular applications.

Granatelli reports gains of up to approximately 12 horsepower naturally aspirated and 25 horsepower on supercharged, turbocharged or nitrous combinations, depending on the engine and condition of the existing ignition system. For a boosted Mustang GT, modified SVT Lightning or another high-performance Ford 2V build, the ignition system should be treated as part of the complete performance combination — not an afterthought.

Shop Granatelli Ford 4.6L & 5.4L 2V 65K Coils

Shop Granatelli 28-1697SC Pro Series Xtreme 65,000-Volt Ford 2V Coils

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Written by JoJo Granatelli — third generation at Granatelli Motor Sports in Oxnard, California, and the one who drives what the company builds. He set a quarter-mile record of 7.06 seconds at 157 mph at Famoso Dragstrip in August 2026. More about JoJo.