Upgrading the Exhaust Manifold On Dodge Ram Diesel

If you’re seeking to improve the performance, reliability, and life of your Dodge Ram diesel engine, then an upgrade of the exhaust manifold is a worthy project. Exhaust manifolds that come factory on your diesel truck can twist, crack, and restrict flow, especially under loads or with towing materials.

The aftermarket manifolds improve exhaust flow, allowing the engine to breathe more freely, and can help cool exhaust gas temperatures (EGTs) if you’re running a diesel engine. Regardless of whether you’re trying to achieve a higher horsepower or just want your Ram to breathe better, this upgrade is valuable and produces tangible results.

Why You Should Upgrade Your Exhaust Manifold?

Upgrading the exhaust manifold on your Dodge Ram diesel isn’t only about increasing power, but it’s also durability and improved flow. Stock exhaust manifolds typically crack and warp under heat and pressure, especially when towing or performing heavy-duty work. Aftermarket exhaust manifolds are typically made of stronger materials, provide better flow characteristics, and heat resistance.

By replacing your OEM manifold with a quality aftermarket manifold, you can reduce exhaust gas temps, improve turbo spool, and overall engine performance. If you want your diesel truck to run cooler, have improved exhaust flow, and last longer, then upgrading the exhaust manifold is a good choice.

One-Piece vs Multi-Piece Manifolds

When comparing one-piece vs. multi-piece exhaust manifolds for your Dodge Ram diesel, the choice comes down to heat tolerance, durability, and long-term performance—especially under heavy loads or high temperatures.

One-Piece Exhaust Manifolds

Design: Cast as a single solid unit.

Pros: Simple, cost-effective, and easy to install.

Cons: Less capable of handling extreme thermal expansion. Under prolonged stress—like towing or hard acceleration—these can warp or crack, leading to exhaust leaks and performance issues.

Best for: Light-duty use or stock setups with minimal upgrades.

Multi-Piece Exhaust Manifolds

Design: Typically made of 2 or 3 separate pieces bolted together, often with expansion joints or slip connections.

Pros: Allows each section to expand and contract independently. This reduces the chances of warping, minimizes cracking, and helps maintain a tight seal under fluctuating temperatures.

Durability: Better suited for high-performance setups, heavy towing, or trucks with tuned engines and upgraded turbos.

Best for: Long hauls, hard-working diesel trucks, or anyone looking to future-proof their build.

Exhaust Manifold Bolt Kits

• Exhaust Manifold Bolts for 03-07 5.9L Cummins 24V
• Exhaust Manifold to Turbo Mounting Studs / Nuts for 89-07 5.9L Cummins 12V 24V
• Exhaust Manifold to Cylinder Head Mounting Studs / Nuts for 89-20 5.9L 6.7L Cummins 12V 24V
• 10.9 Exhaust Manifold Bolt Kit for 94-03 7.3L Powerstroke
• Exhaust Manifold Bolts for 03-10 6.0L Powerstroke
• Exhaust Up-Pipe Gasket Bolt Nut Kit for 94-03 7.3L Powerstroke
• Exhaust Manifold Gasket Bolt Kit for 94-03 7.3L Powerstroke
• Exhaust Manifold Gaskets + Bolts for 03-10 6.0L Powerstroke

Guide to Upgrading Your Exhaust Manifold

Upgrading the exhaust manifold on your Dodge Ram diesel involves several steps and some mechanical skill. Here’s a general guide:

1. Choose the Right Manifold

• Select a high-quality one-piece or multi-piece aftermarket manifold designed for your Ram model and engine (e.g., 5.9L or 6.7L Cummins).

2. Prepare the Vehicle

• Let the engine cool completely.
• Disconnect the battery.
• Remove any components blocking access to the manifold (heat shields, intake piping, etc.).

3. Remove the Old Manifold

• Carefully unbolt the manifold from the engine head
• Disconnect the turbo if it’s mounted to the manifold.
• Inspect studs and bolts; replace any that are corroded or damaged.

4. Clean the Surface

• Scrape off any old gasket material or carbon buildup from the mounting surface.
• Ensure the surface is flat and clean for a good seal.

5. Install the New Manifold

• Use new gaskets and hardware.
• Follow the torque specs and pattern recommended by the manufacturer.
• Reconnect the turbo if necessary.

6. Reconnect Everything

• Reinstall any parts you removed earlier (heat shields, intake, sensors).
• Double-check all bolts and fittings.

7. Start the Engine and Test

• Let it idle and check for leaks.
• Take a short test drive to ensure proper performance and no exhaust leaks.

What Size is Best?

Depending on what turbo you choose to upgrade to in the future, you may need to change the manifold to one that has a different turbo flange or will accept a turbo flange adapter. The most likely scenario, if you are upgrading, is that you are upgrading to a bigger turbo. What does that mean?

That means you need to pay attention to the flange on the turbo and the manifold you are using if you want it all to fit. Most turbos are mounted with either T3 or T4 flanges, and you will need to make sure that your manifold matches for a proper fit.

There are numerous T flanges that go beyond T3 and T4, and they come in all different sizes. Understanding the flange type, stock or aftermarket, is important when selecting an upgraded exhaust manifold.

Final Thoughts

Upgrading the exhaust manifold on your Dodge Ram diesel isn’t just an upgrade for performance, but it’s a long-term investment in the reliability of your truck. Whether you’re trying to add some horsepower, lower your EGTs, or avoid thermal failures that are commonplace with stock exhaust manifolds, the aftermarket upgrade is worth its weight in performance gains.

Choosing a one-piece or multi-peice exhaust manifold depends on how hard you work your truck and your performance expectations. With the proper manifold and proper installation, your diesel engine will run cooler, pull harder, and stay stronger for thousands of miles to come.