S13 Exhaust System Routing And Hanger Locations

The Nissan S13, a darling of the drift and tuning community, possesses a chassis that's relatively simple yet remarkably adaptable. Understanding the intricacies of its exhaust system, specifically the routing and hanger locations, is crucial for anyone seeking to modify, repair, or simply appreciate the engineering that went into this iconic car. This guide delves into the details of the S13 exhaust system, providing an analytical look at its design and functionality.

Exhaust System Overview

The exhaust system's primary role is to safely and efficiently expel the burnt gases from the engine's combustion chambers. In the S13, this involves several key components working in concert: the exhaust manifold (or header), the downpipe, the catalytic converter (in some markets), the mid-pipe, and the muffler (or silencer). Each of these plays a vital part in reducing emissions, noise, and optimizing engine performance.

Exhaust Manifold (Header)

The journey begins at the engine's exhaust ports, where the exhaust manifold collects the high-temperature, high-pressure gases. The S13's stock exhaust manifold is typically a cast iron design, known for its durability but often criticized for its flow restrictions. Aftermarket options, such as tubular headers, are popular upgrades for improved exhaust flow and, consequently, increased horsepower. These headers can be either equal-length or unequal-length, each offering different performance characteristics. Equal-length headers are designed to have runners of the same length, promoting balanced exhaust pulses and potentially improving mid-range power. Unequal-length headers, while often more affordable, can contribute to a distinct exhaust note favored by some enthusiasts.

Downpipe

Connected directly to the exhaust manifold is the downpipe. This section is responsible for directing the exhaust gases downwards and towards the rest of the exhaust system. The stock downpipe often incorporates a catalytic converter (depending on the year and market), which reduces harmful emissions. Aftermarket downpipes often eliminate the catalytic converter (for off-road use only) and feature larger diameters to improve exhaust flow. The flange connecting the downpipe to the exhaust manifold is a critical point, requiring a robust gasket to prevent leaks. The routing of the downpipe must carefully avoid interfering with other components, such as the steering shaft and chassis members.

Catalytic Converter (If Equipped)

The catalytic converter is a vital component for reducing pollutants like hydrocarbons, carbon monoxide, and nitrogen oxides. It contains a catalyst that promotes chemical reactions to convert these harmful gases into less harmful substances. While essential for emissions control, the catalytic converter can also restrict exhaust flow, particularly as it ages and becomes clogged. Many aftermarket exhaust systems offer high-flow catalytic converters or delete them entirely (again, for off-road use only) to improve performance.

Mid-Pipe

The mid-pipe connects the downpipe (or catalytic converter) to the muffler. Its primary function is to further direct the exhaust gases and provide additional space for sound dampening components like resonators. The length and diameter of the mid-pipe can significantly influence the exhaust note and overall performance. A longer mid-pipe can help to reduce drone, while a larger diameter can improve exhaust flow. The mid-pipe often includes a flex joint, a section of corrugated or braided metal, to absorb vibrations from the engine and prevent stress on the exhaust system components.

Muffler (Silencer)

The muffler is the final component in the exhaust system and is responsible for reducing exhaust noise. It typically consists of a series of chambers and baffles that dampen sound waves. Mufflers come in various designs, each offering different levels of sound reduction and performance characteristics. Straight-through mufflers offer minimal restriction to exhaust flow but provide less sound dampening. Chambered mufflers provide more sound dampening but can restrict exhaust flow to some extent. The choice of muffler depends on the desired balance between performance and noise level. Many S13 owners opt for aftermarket mufflers with a deeper, more aggressive exhaust note.

Exhaust System Routing

The routing of the S13 exhaust system is carefully designed to maximize ground clearance and avoid interference with other vehicle components. From the exhaust manifold, the downpipe typically routes downwards and towards the passenger side of the car. It then passes underneath the transmission and connects to the mid-pipe. The mid-pipe runs along the center of the car, underneath the driveshaft and fuel tank, before connecting to the muffler at the rear. Careful attention is paid to keeping the exhaust system away from fuel lines, brake lines, and other critical components to prevent heat damage or other issues.

Ground clearance is a significant consideration, especially for lowered S13s. Aftermarket exhaust systems are often designed with flatter sections to maximize ground clearance and minimize the risk of scraping on speed bumps or uneven surfaces. The routing also needs to account for the movement of the engine and chassis under acceleration, braking, and cornering.

Exhaust Hanger Locations

Exhaust hangers are crucial for supporting the weight of the exhaust system and preventing it from vibrating against the chassis. The S13 exhaust system typically uses several hangers strategically located along its length. These hangers usually consist of rubber bushings or straps that absorb vibrations and allow for some movement. Here's a typical breakdown of hanger locations:

Downpipe Hanger: Usually located near the connection between the downpipe and the transmission, this hanger supports the weight of the downpipe and helps to prevent stress on the exhaust manifold.
Mid-Pipe Hangers: Typically, two or three hangers are located along the length of the mid-pipe, evenly distributing the weight and preventing sagging. These hangers are often attached to the chassis using bolted brackets.
Muffler Hangers: The muffler is usually supported by two or three hangers, often located near the rear of the car. These hangers are particularly important, as the muffler is the heaviest component of the exhaust system.

The condition of the exhaust hangers is critical for preventing exhaust leaks and damage to the exhaust system. Over time, the rubber bushings in the hangers can deteriorate, crack, or break, causing the exhaust system to sag and vibrate excessively. This can lead to exhaust leaks, rattles, and even damage to the exhaust manifold or other components. Regularly inspecting the exhaust hangers and replacing them as needed is essential for maintaining the health of the exhaust system.

Common Issues and Solutions

Several common issues can arise with the S13 exhaust system:

Exhaust Leaks: Exhaust leaks can occur at any point in the system, but they are most common at the flanges connecting the different components. These leaks can cause a loss of power, reduced fuel economy, and increased emissions. Replacing gaskets and tightening bolts can often resolve minor exhaust leaks. In more severe cases, welding may be required.
Rattling: Rattling is often caused by loose exhaust hangers or by the exhaust system contacting the chassis. Tightening loose hangers or adjusting the position of the exhaust system can usually resolve this issue.
Drone: Drone, a low-frequency humming noise, is a common complaint with aftermarket exhaust systems. It is often caused by resonant frequencies in the exhaust system. Adding a resonator or changing the muffler can often reduce or eliminate drone.
Ground Clearance Issues: As mentioned earlier, lowered S13s are particularly susceptible to ground clearance issues with the exhaust system. Installing a more compact exhaust system or raising the ride height can help to prevent scraping.

Modifications and Upgrades

The S13 exhaust system is a popular target for modifications and upgrades. Many owners choose to install aftermarket exhaust systems to improve performance, enhance the exhaust note, or simply customize the appearance of their car. Common upgrades include:

Aftermarket Headers: Tubular headers offer improved exhaust flow and increased horsepower compared to the stock cast iron manifold.
High-Flow Catalytic Converters: High-flow catalytic converters reduce emissions while minimizing restriction to exhaust flow.
Cat-Back Exhaust Systems: Cat-back exhaust systems replace everything from the catalytic converter to the muffler, offering a complete performance and sound upgrade.
Axle-Back Exhaust Systems: Axle-back exhaust systems replace only the muffler and the tailpipe, providing a more subtle upgrade.

When choosing an aftermarket exhaust system, it's essential to consider the desired performance characteristics, sound level, and budget. It's also crucial to ensure that the system is compatible with the S13 chassis and meets all applicable emissions regulations. Proper installation is critical for ensuring optimal performance and preventing leaks or other issues.

Conclusion

The S13 exhaust system is a relatively straightforward design, but understanding its intricacies is essential for anyone seeking to modify, repair, or maintain this iconic car. By carefully considering the routing, hanger locations, and potential issues, owners can ensure that their exhaust system is functioning optimally and contributing to the overall performance and enjoyment of their S13.