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Building a high-performance street motor capable of producing over 700 horsepower is a significant undertaking for any automotive enthusiast. Two popular engine platforms for this kind of build are the LS and HEMI engines. Both have their unique characteristics, advantages, and challenges when it comes to internal components, turbocharging, and supporting modifications. In this article, we will compare the LS and HEMI platforms, focusing on their internals, turbo systems, and additional modifications needed to achieve that coveted 700+ horsepower mark.
Understanding the LS Engine Platform
The LS engine family, developed by General Motors, has gained a reputation for its robust design and performance potential. These engines are lightweight, compact, and have a high power-to-weight ratio, making them popular choices for street and race applications.
LS Internals
When building an LS engine for 700+ horsepower, the choice of internals is crucial. Key components include:
- Pistons: Upgrading to forged pistons is essential for handling the increased power and boost.
- Rods: Forged connecting rods provide the strength needed to withstand high RPMs and stress.
- Cylinder Heads: High-flow cylinder heads improve airflow and combustion efficiency.
- Camshaft: A performance camshaft tailored for forced induction can significantly enhance power output.
Turbos for LS Engines
Turbocharging an LS engine can easily push it over the 700 horsepower threshold. Consider the following:
- Turbo Size: Selecting the right turbo size is critical for achieving the desired power band.
- Intercooler: An efficient intercooler will help lower intake temperatures and increase performance.
- Exhaust System: A free-flowing exhaust system minimizes back pressure and maximizes turbo efficiency.
Supporting Mods for LS Builds
To support the increased power from an LS build, consider these modifications:
- Fuel System: Upgrading to high-flow injectors and a larger fuel pump is necessary to meet the fuel demands.
- Tuning: A professional tune is vital for optimizing performance and ensuring reliability.
- Cooling System: An upgraded radiator and cooling fans help manage engine temperatures during high-performance driving.
Exploring the HEMI Engine Platform
The HEMI engine, known for its unique hemispherical combustion chamber design, has become synonymous with power and performance. This platform is favored by many for its ability to produce substantial horsepower with the right modifications.
HEMI Internals
When building a HEMI engine for 700+ horsepower, the choice of internals is equally important. Key components include:
- Pistons: Forged pistons are recommended for high horsepower builds to ensure durability.
- Rods: Upgrading to forged rods enhances strength and reliability under extreme conditions.
- Cylinder Heads: High-performance heads are essential for maximizing airflow and power output.
- Camshaft: A camshaft designed for forced induction can significantly increase horsepower.
Turbos for HEMI Engines
Turbocharging a HEMI engine can also help achieve over 700 horsepower. Consider the following:
- Turbo Selection: Choosing the right turbo size and type is essential for optimal performance.
- Intercooling: An efficient intercooler setup helps maintain lower intake temperatures.
- Exhaust System: Upgrading to a high-flow exhaust system reduces back pressure and enhances turbo performance.
Supporting Mods for HEMI Builds
To support the increased power from a HEMI build, consider these modifications:
- Fuel System: High-flow fuel injectors and pumps are necessary to meet the engine’s fuel requirements.
- Tuning: A professional tune is crucial for maximizing performance and ensuring engine longevity.
- Cooling System: Upgrading the cooling system helps maintain optimal engine temperatures during high-performance use.
Comparing LS and HEMI Platforms
Both LS and HEMI engines have their strengths and weaknesses when it comes to building a 700+ horsepower street motor. Here are some key comparisons:
- Weight: LS engines are generally lighter, which can improve overall vehicle performance.
- Aftermarket Support: The LS platform has a vast aftermarket support network, making parts and upgrades more accessible.
- Power Delivery: HEMI engines often provide a different power delivery characteristic, which some enthusiasts prefer.
- Cost: Depending on the specific build, costs may vary significantly between the two platforms.
Conclusion
Building a 700+ horsepower street motor is an exciting challenge, whether you choose the LS or HEMI platform. Both engines offer unique advantages and require specific modifications to achieve high power levels. By understanding the internals, turbo systems, and supporting modifications necessary for each platform, enthusiasts can make informed decisions and create powerful, reliable street motors that deliver exhilarating performance.