Why does the Hemi 5.7 have 16 spark plugs?
The Hemi 5.7-liter V8 engine, a popular choice in many Dodge, Chrysler, and Jeep vehicles, features an unusual design with 16 spark plugs. This configuration serves a specific purpose that enhances the engine's performance and efficiency.
Dual Spark Ignition System
The Hemi 5.7 engine utilizes a dual spark ignition system, which means that each cylinder has two spark plugs. This design provides several benefits:
- Improved Combustion: The dual spark plugs in each cylinder help to ignite the air-fuel mixture more evenly and completely, leading to a more efficient combustion process.
- Enhanced Performance: The dual ignition system allows for a faster, more controlled burn of the air-fuel mixture, resulting in increased power output and improved engine responsiveness.
- Reduced Emissions: The more complete combustion achieved with the dual spark plugs helps to reduce the amount of unburnt fuel and emissions, making the engine more environmentally friendly.
The use of 16 spark plugs in the Hemi 5.7 engine is a key feature that contributes to its reputation for power, efficiency, and clean operation.
Cylinder Head Design
The Hemi 5.7 engine's cylinder head design is another factor that necessitates the use of 16 spark plugs. The engine's hemispherical combustion chambers require two spark plugs per cylinder to ensure optimal ignition and combustion.
This unique cylinder head design, which features a dome-shaped combustion chamber, allows for a more efficient air-fuel mixture flow and improved thermal efficiency compared to traditional flat-top cylinder heads.
The combination of the dual spark ignition system and the hemispherical combustion chambers makes the Hemi 5.7 engine a highly advanced and capable powerplant, delivering impressive performance and efficiency.
Why are there 16 spark plugs on Hemi?
Modern HEMI V8 engines have 16 spark plugs (two per cylinder) to create a faster, more complete combustion, which improves performance, fuel economy, and emissions. The hemispherical combustion chamber of a HEMI is efficient for airflow, but the deep dome shape makes it difficult for a single spark plug to ignite the entire fuel-air mixture quickly. Placing a second spark plug on the opposite side of the cylinder allows the two flame fronts to meet, ensuring a more complete burn and smoother operation, especially at high RPMs.
This video explains why some HEMI engines use 16 spark plugs: 58sThe Enthusiast MechanicYouTube · Jul 26, 2024
Key reasons for dual spark plugs
- More complete combustion: The two plugs ensure the entire fuel-air mixture is burned more efficiently, reducing wasted fuel.
- Improved performance: A more complete burn translates to a slight increase in horsepower and better throttle response.
- Better emissions: By burning fuel more completely, the engine produces fewer harmful emissions.
- Smoother operation: Dual ignition points provide a more stable and consistent power stroke, which can improve cold starts and idle quality.
- Address the hemispherical design: The unique shape of the HEMI's combustion chamber requires two ignition points for optimal efficiency, as a single plug cannot effectively ignite the entire volume of the chamber.
Why does a 5.7 Hemi have two spark plugs per cylinder?
Chamber. Obviously this takes some time and the amount of time required to complete the combustion depends on the flame speed of the combustion.
Which spark plugs are best for a 5.7 Hemi?
Here's a detailed guide: For the Dodge Ram 1500 with a 5.7L Hemi engine, the recommended spark plug is typically the Champion 3570 or NGK LZFR5C-11. These are platinum-tipped spark plugs commonly used for this engine model.
Can a V8 have 16 spark plugs?
With four in them. And a lot of people don't know this but the fun fact is that each cylinder on this particular engine runs two spark plugs. And even has a coil pack that has twin leads for output.
