With stricter emission standards in the early 2000s, Caterpillar introduced the C15 ACERT engine, featuring Advanced Combustion Emissions Reduction Technology. This included intake valve actuators (IVAs) and a compound turbocharger arrangement. However, this complex system led to complaints about turbo lag, replacement costs, and difficult maintenance. As a result, many owners have opted for single turbo conversion kits for their C15 CAT engines. This article explores the reasons behind this trend, the conversion process, and the pros and cons of a single turbo system.
Simplicity: A Major Draw for Single Turbo Kits
While a single turbo conversion for a C15 ACERT is a significant undertaking with a price tag often exceeding $5,000, it drastically simplifies the engine. Eliminating one turbocharger reduces the risk of failure and the simplified intake and exhaust plumbing minimizes potential boost and drive pressure leaks. A single turbo also creates more working space on the passenger side of the engine.
Cooler EGT and Improved Fuel Economy with Single Turbo Conversions
Beyond simplicity, single turbo conversions on C15 ACERT engines often lead to cooler operating temperatures and improved fuel efficiency. A properly sized single turbo, combined with appropriate ECM tuning, can result in lower exhaust gas temperatures (EGT) compared to the factory compound turbos. The performance gains from tuning, coupled with cooler engine operation, contribute to better fuel economy.
Cost Considerations for C15 CAT Single Turbo Kits
While the initial investment for a single turbo conversion is high, the long-term cost benefits can be significant. Replacing the factory compound turbo setup on a C15 ACERT is expensive. A single, readily available BorgWarner S400-based turbo offers a more affordable and easily replaceable alternative, potentially reducing downtime and repair costs.
Reduced Engine Stress with a Single Turbo
Compound turbo systems multiply boost and drive pressure. While manageable at stock power levels, increased horsepower can lead to excessive pressures, potentially damaging the head gasket. A properly sized single turbo generates lower overall pressures, reducing stress on the head gasket and improving engine longevity.
Components of a Single Turbo Conversion Kit for C15 CAT
A comprehensive single turbo conversion kit for a C15 ACERT typically includes a new exhaust manifold, turbo downpipe, oil lines, air cleaner piping, and charge air cooler piping. Various other components like intercooler boots, clamps, adapter fittings, hardware, and gaskets are also necessary.
The BorgWarner S430: A Popular Choice for Single Turbo Conversions
The BorgWarner S430 turbocharger is a common choice for C15 ACERT single turbo conversions. Its robust construction, affordability, and ability to support 425-600 hp make it a reliable option. Upgrades like a 360-degree thrust bearing and larger exhaust housings are available for higher horsepower applications.
Performance Options for Single Turbo C15 CAT Engines
For higher horsepower goals, options like titanium compressor wheels, optimized designs, and larger wheels are available. An Air Tec Innovations S430 with a titanium 78mm compressor wheel can support up to 750 hp, while their 80mm version exceeds that.
Compression Ratio Considerations for Single Turbo C15 CAT
Lowering the compression ratio isn’t always necessary for a single turbo conversion. For power levels below 550 hp, the factory 18:1 compression is often sufficient. Lower compression pistons are generally recommended for builds exceeding 600 hp.
ECM Tuning: Essential for Optimizing a Single Turbo System
Proper ECM tuning is crucial for maximizing the benefits of a single turbo conversion. A well-tuned ECM ensures optimal performance, drivability, fuel efficiency, and minimizes turbo lag.
The Case for Retaining the Compound Turbo System
While single turbo conversions are popular, the factory compound turbo system, when properly tuned, can offer excellent performance and drivability. For those prioritizing drivability and moderate horsepower, sticking with the compounds and investing in tuning can be a viable option. However, for significant horsepower increases, a single turbo conversion is often necessary.
