6.7 Powerstroke 4 Inch Exhaust: Benefits, Kits & Install Guide

Introduction to 6.7 Powerstroke 4 Inch Exhaust

Having the right exhaust system on your Ford 6.7L Powerstroke diesel truck is crucial for performance, fuel economy, and the overall health of your engine. Many truck owners choose to upgrade to a 4 inch exhaust system to help their Powerstroke breathe easier and see improvements across the board. In this comprehensive guide, we'll look at the benefits of switching to a 4 inch exhaust on the 6.7L Powerstroke, compare different exhaust system designs, and review some top-rated exhaust kit options for these powerful trucks.

Benefits of a 4 Inch Exhaust on the 6.7 Powerstroke

The 6.7L Power Stroke turbo diesel engine comes equipped from the factory with a restrictive 3 inch exhaust. While this is sufficient for stock power levels, it creates excessive backpressure once modifications like a tuner, intake, and bigger injectors are added. By upgrading to a less restrictive 4 inch system, you can realize significant benefits:

• Increased horsepower and torque - Less backpressure allows the engine to breathe better and make more power throughout the RPM range.
• Improved throttle response - Narrow stock exhaust restricts exhaust flow, hampering throttle response. A wider 4 inch system improves flow and makes the engine more responsive.
• Better EGT management - By reducing exhaust backpressure, EGTs are lowered which reduces heat soak and eases loading on the turbocharger and engine.
• Enhanced turbocharger performance - Lower EGTs and reduced backpressure keep the turbo running cooler while allowing it to spool up faster for better boost response.
• Increased fuel economy - The engine doesn't have to work as hard with an exhaust that flows freely, improving MPG.
• Better sound - A 4 inch exhaust paired with a performance muffler gives the 6.7L Powerstroke a much more aggressive exhaust tone.

Exhaust System Designs for the 6.7 Powerstroke

Several types of exhaust systems are available for the 6.7L Powerstroke diesel trucks. Each has its pros and cons:

Single Exhaust

Uses a single 4 inch diameter exhaust pipe from the turbocharger back. Simple, budget friendly design, but doesn't allow for as much flow capacity as a dual exhaust setup.

Dual Exhaust

Utilizes two 3 inch or 4 inch exhaust pipes instead of a single large one. This design doubles the exhaust flow capacity compared to a single exhaust and is ideal for highly modified trucks making over 800 horsepower.

Diesel Particulate Filter (DPF) Back Exhaust

Keeps the stock DPF system intact while replacing the exhaust piping after it. This is a great option for mild truck builds wanting better flow while retaining the factory DPF.

DPF Delete Exhaust

Removes the diesel particulate filter altogether and uses a 4 inch straight pipe or muffler in its place. DPF deletes are illegal for street use, but popular with truck pullers and off-road racers.

Exhaust with Muffler Delete

Eliminates the muffler for maximum noise and flow. Muffler deletes sound aggressive but are very loud inside the cab at highway speeds.

Top 4 Inch Exhaust Kits for the 6.7L Powerstroke

MBRP 4" Single Exhaust System

MBRP is one of the most trusted names in diesel truck exhaust systems. Their 4 inch single exhaust kit for the late model Powerstroke trucks is designed to boost performance and includes the following components:

• 18-gauge 4" mandrel bent intermediate pipe
• 4" turbo outlet pipe with H-pipe crossover
• 4" stainless steel MBRP Series exhaust tip
• All necessary clamps, hangers, and hardware

Made from premium materials in the USA, this kit will add power while giving your truck an aggressive exhaust note. MBRP also backs it with a limited lifetime warranty.

Flo-Pro 4" DPF Back Dual Exhaust

From respected brand Flo-Pro, this DPF back 4 inch dual exhaust kit keeps the factory diesel particulate filter in place while improving flow with a dual exhaust design. Kit includes:

• (2) 4” mandrel bent stainless steel intermediate pipes
• (2) 4” mandrel bent stainless steel over-axle pipes
• (2) 4” stainless steel exit pipes with 4” angle cut tips
• Laser cut 409 stainless steel components

With this kit, you'll get reduced EGTs, lower smoke, and improvements in horsepower and throttle response while retaining the factory DPF.

Sinister Diesel DPF Delete Exhaust

Ready to ditch the restrictive factory DPF altogether? Sinister Diesel is known for their top quality DPF delete kits designed for off-road use. Their 4 inch DPF delete exhaust for the 6.7L Powerstroke includes:

• 4” downpipe back exhaust system
• 409 stainless steel construction
• Mandrel bent for maximum flow
• Compatible with OEM and aftermarket up-pipe
• Includes clamps, hangers, and installation hardware

Remove that DPF and experience huge gains in horsepower and torque with this free-flowing DPF delete system.

Diamond Eye 4” Straight Pipe Exhaust

For truck owners on a tighter budget, this Diamond Eye straight pipe kit provides big exhaust flow at an affordable price. It features:

• 4” mandrel bent front pipe
• 4” straight rear pipe section
• Stainless steel construction
• Slip fit connections
• 4” stainless steel exhaust tip

Overall a great entry level 4 inch exhaust upgrade for the 6.7L Ford Powerstroke diesel pickups.

Installing a 4 Inch Exhaust on Your Truck

While it is possible to install a 4 inch exhaust system yourself in your driveway, it requires some fabrication skills and the right tools. Most truck owners choose to have their new exhaust installed by a professional shop for the best fitment and results. A typical shop will charge around $800-$1000 for complete removal of the old exhaust and installation of the new system including parts and labor. This is money well spent to make sure your brand new exhaust goes on correctly. The last thing you want is exhaust leaks, which can negatively affect performance and potentially lead to carbon monoxide entering the cabin.

When done properly, upgrading to a 4 inch exhaust system can transform the personality and performance of your 6.7L Ford Powerstroke diesel pickup. Just make sure to select quality components designed specifically for your truck's year and cab style. With the right exhaust kit, you'll be enjoying reduced EGTs, crisper throttle response, and best of all - more torque and horsepower every time you put your foot down.

FAQs

Will a 4 inch exhaust void my truck's factory warranty?

In most cases, no - installing an aftermarket exhaust will not automatically void your factory powertrain or emissions warranty. However, if Ford can prove the exhaust caused a related failure, they may deny a claim.

What are the biggest benefits of a 4 inch exhaust?

A 4 inch exhaust system improves power, torque, throttle response, turbo performance, EGTs, and fuel economy on modified 6.7L Powerstroke trucks. It also gives the engine a deeper, throatier exhaust tone.

Is it legal to delete the DPF?

No, removing the diesel particulate filter is prohibited by federal emissions laws. DPF deletes can only be used for off-road applications like racing or pulling competitions.

Should I get a single or dual exhaust system?

For mild to moderate truck builds, a single 4 inch exhaust is sufficient. But for heavily modified trucks making over 800 hp, a dual exhaust design is recommended to handle the higher volume of exhaust flow.