We researched, compared, and evaluated the most popular modifications for the 6.7L Cummins diesel engine using manufacturer specifications, published industry standards, and aggregated owner feedback. This guide covers seven essential mods that can improve performance, durability, and drivability. Our evaluation focuses on real-world benefits and limitations to help you make an informed decision.
| Photo | Product | Score | Buy |
|---|---|---|---|
 |
Edge Products CTS3 Insight Pro Monitor and Tuner Best Tuner 5.7-inch color touchscreen, up to 150 HP gain, EGT/Boost/Trans temp monitoring |
9.2 | 🛒 Check Price |
 |
S&B Filters 75-5096 Cold Air Intake Best Cold Air Intake Dry filter, no oil, fits 2013-2018 6.7L, gains 10-15 HP |
8.9 | 🛒 Check Price |
 |
MBRP S5214308 4-inch Turbo Back Exhaust Best Exhaust 4-inch aluminized steel, turbo back, single exit, muffler delete option |
8.7 | 🛒 Check Price |
 |
BD Diesel 1030700 Exhaust Manifold Best Exhaust Manifold Cast iron, stock replacement, fits 2007-2018 6.7L |
8.2 | 🛒 Check Price |
 |
FASS 100GPH Titanium Signature Series Fuel System Best Fuel System 100 gallons per hour, 2-micron filtration, includes lift pump and filter kit |
8.4 | 🛒 Check Price |
 |
Sinister Diesel EGR Delete Kit Best EGR Delete Includes block-off plates, gaskets, and hardware, fits 2007-2018 |
7.8 | 🛒 Check Price |
 |
AEM 21-811C DryFlow Air Filter Best Drop-In Filter DryFlow, washable, reusable, fits stock air box, 2013-2018 6.7L |
7.3 | 🛒 Check Price |
1. Edge Products CTS3 Insight Pro Monitor and Tuner: Best Tuner
The Edge CTS3 Insight Pro is a top-tier tuner and monitor combo that we researched extensively. Manufacturer specs indicate up to 150 horsepower gains on the highest performance tune, while owner feedback highlights the intuitive touchscreen and the ability to monitor critical parameters like EGT and boost. However, we noted that some users experienced occasional connectivity issues with the OBDII port, and the device may be considered overkill for those who only want a simple tune.
This mod is ideal for owners who want both tuning and monitoring in one package. Skip this if you prefer a standalone tuner or are on a tight budget, as there are more affordable options that still provide significant gains.
- Combines a powerful tuner with a comprehensive multi-gauge monitor
- Pre-loaded tunes for towing, economy, and performance
- Includes EGT, boost, transmission temperature, and DPF regeneration monitoring
Pros: Easy to use touchscreen interface with customizable layouts; Real-time data logging and alarm capabilities
Cons: Higher price point compared to basic tuners
2. S&B Filters 75-5096 Cold Air Intake: Best Cold Air Intake
We compared the S&B 75-5096 against other cold air intakes and found its dry filter design to be a standout for durability. Owner feedback consistently praises the build quality and the fact that it never needs re-oiling. According to the manufacturer, it flows enough for up to 650 horsepower, making it suitable for moderately tuned trucks. However, in our evaluation, the actual power increase on a stock truck is subtle, and some users reported that the filter can get dirty quickly in off-road conditions.
This intake is a great choice for those prioritizing filtration and low maintenance. Skip it if you want maximum horsepower gains from an intake alone, as a wet filter or a larger diameter tube might offer more flow.
- Dry synthetic filter with 5-layer filtration, no oil required
- Sealed aluminum intake box with clear lid for visual inspection
- Includes pre-filter for dusty conditions
Pros: Excellent filtration efficiency without the risk of oil contamination; Easy installation with no cutting or drilling
Cons: Horsepower gains are modest compared to some competitors
3. MBRP S5214308 4-inch Turbo Back Exhaust: Best Exhaust
The MBRP S5214308 is a popular turbo-back exhaust system that we evaluated based on owner feedback and flow data. Users report noticeable turbo spool improvement and a 1-2 mpg increase in fuel economy when combined with a tune. The aluminized steel construction is durable but not stainless, which could be a concern in corrosive environments. We also found that the muffler delete version can be very loud, which may not suit everyone.
This exhaust is a solid pick for those wanting improved flow and a sporty sound. Skip it if you live in an area with heavy road salt, or if you need a stainless system for longevity.
- Mandrel bent 4-inch tubing for maximum flow
- Includes all necessary clamps and hangers
- Available with or without muffler
Pros: Significant reduction in exhaust backpressure; Deep, aggressive sound without being obnoxious (with muffler)
Cons: Aluminized steel may rust in salt-belt regions
4. BD Diesel 1030700 Exhaust Manifold: Best Exhaust Manifold
The BD Diesel exhaust manifold is a direct replacement that we researched after noting widespread reports of OEM manifold failures. Owner feedback highlights its durable cast iron build and improved durability under high EGT conditions. However, in our evaluation, the installation is challenging due to tight access on the 6.7L, and some users had to remove the turbo for proper fitment. The price is also higher than a stock replacement but justified by the longevity.
This mod is for owners who have experienced or want to prevent manifold cracks. Skip it if you are not experiencing issues and prefer to keep the truck stock, or if you are not comfortable with a complex DIY job.
- Heavy-duty cast iron construction resists cracking
- Direct fit with no modifications required
- Reinforced design compared to OEM
Pros: Much stronger than factory manifold; Eliminates common cracking issues
Cons: Installation is labor-intensive and may require special tools
5. FASS 100GPH Titanium Signature Series Fuel System: Best Fuel System
The FASS Titanium Signature Series fuel system is a popular upgrade for 6.7 Cummins owners concerned about CP4 pump failures. We compared its filtration specs and flow rates against other aftermarket systems. Owner feedback consistently reports added security and improved performance. However, installation is moderately difficult and not a simple plug-and-play. The unit is also bulky and may require mounting in a specific location.
This mod is highly recommended for those who tow heavy or have experienced fuel system issues. Skip it if your truck is stock and you are not planning to increase horsepower significantly, as the stock system may suffice.
- Provides clean, de-aerated fuel to the injection system
- Reduces risk of injector failure from contamination
- Includes a high-flow lift pump with pressure regulator
Pros: Protects expensive CP4 injection pump; Noticeable improvement in throttle response
Cons: Installation requires cutting and splicing fuel lines
6. Sinister Diesel EGR Delete Kit: Best EGR Delete
The Sinister Diesel EGR delete kit is a very popular for the 6.7 Cummins. We researched its construction and found the block-off plates to be well-machined. Owner feedback indicates a reduction in intake buildup and slightly lower EGTs. However, we must emphasize that removing EGR systems is illegal for street use in most states and can void your warranty. Additionally, installation is time-consuming and requires removing the intake horn.
This mod is intended for off-road or competition use only. Skip it if you need to pass emissions testing or plan to drive on public roads legally.
- Removes EGR cooler and valve to reduce soot buildup
- Includes CNC-machined aluminum block-off plates
- Comes with stainless steel gaskets for a leak-free seal
Pros: Eliminates common EGR cooler failure points; Improves engine bay cleanliness
Cons: Illegal for on-road use in many areas; emissions components removal may violate federal law
7. AEM 21-811C DryFlow Air Filter: Best Drop-In Filter
The AEM DryFlow filter is a straightforward upgrade that we evaluated for its ease of use. It fits perfectly in the stock air box and requires no tools. Owner feedback is positive regarding filtration and longevity. However, in our comparison, the performance increase is negligible on a stock engine, and some users reported that the filter can let in fine dust if not properly sealed. It is not a substitute for a full cold air intake.
This filter is ideal for owners who want a reusable, low-maintenance option without altering the intake system. Skip it if you are looking for significant power gains or have a heavily modified truck that requires higher flow.
- Direct replacement for factory filter, no modifications needed
- Washable and reusable, lasts up to 100,000 miles between cleanings
- Improves airflow over OEM filter by up to 50%
Pros: Simple installation, just swap out the old filter; Cost-effective over time compared to disposable filters
Cons: Minimal horsepower gains on stock trucks
Frequently Asked Questions
What is the first mod I should do to my 6.7 Cummins?
Most owners recommend starting with a tuner or a monitor to understand your truck’s parameters. A tuner like the Edge CTS3 Insight Pro provides both tuning and monitoring, allowing you to safely add power while keeping an eye on EGTs and other critical data.
Are cold air intakes worth it on a 6.7 Cummins?
Yes, but gains are modest on a stock truck. A cold air intake like the S&B 75-5096 improves filtration and flow, which becomes more beneficial with a tuner or other mods. It also enhances engine sound.
Will an exhaust system void my warranty?
It can, depending on the modification. A turbo-back exhaust that removes the DPF or catalytic converter will likely void emissions-related components. A cat-back system may be less risky, but always check your warranty terms.
Is an EGR delete legal for street use?
No, removing the EGR system is illegal for on-road vehicles in most states and violates federal Clean Air Act. It is intended for off-road or competition use only. You may face fines and fail emissions testing.
How much horsepower can I expect from these mods?
Combined, a tuner, intake, and exhaust can add 50-100 horsepower to a stock 6.7 Cummins. However, individual gains vary. The Edge tuner alone claims up to 150 HP on the highest setting, but that requires supporting mods and careful monitoring.
Our Verdict
After our research and comparison, the Edge Products CTS3 Insight Pro Monitor and Tuner stands out as the top pick for its versatility, power gains, and comprehensive monitoring. For a close runner-up, the S&B Filters 75-5096 Cold Air Intake offers excellent filtration and easy installation, making it a solid first mod. Both provide reliable performance based on owner feedback and manufacturer specs.
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