What size 7.3|6.0 Powerstroke Exhaust system is right for me 4" or 5"?

4 vs 5 inch exhaust


 

We get this question quite often for the sales staff. Depending on your application and interest will determine what size is best for your Powerstroke.

Sound is the biggest difference between the 4" and 5" exhaust systems.

The 4” systems will be the quietest but still give you a louder sound over stock. We typically hear a higher pitched sound with the 4”. The 5” will give you a deeper exhaust tone and will be the loudest. Performance mufflers can also be added to any exhaust system to help rid of drone sounds and quiet down exhaust overall. Typically, if you do a lot of highway driving or want the exhaust as quiet as possible, we would recommend the 4” exhaust system. Both size exhaust systems will give you more turbo noise also.

 

Performance gains can be achieved with the 4” and 5” exhaust systems.

So what performance gains are made with each of these two systems. What are the requirements to install each? We usually find that the 4” exhaust systems work the best up to 450-500 hp applications and typically have more bottom end torque compared to the 5” within this power range. Over 500 hp can benefit even more from a 5” exhaust system to maximize airflow for any turbo capable of the 500hp+ mark.

 

Installing a 5” exhaust system will dissipate heat quicker and lower your EGT’s (Exhaust Gas Temps) even more compared to a 4” exhaust system. Factory exhaust systems have many restrictions that cannot keep up with a modified engine compared to an aftermarket performance exhaust that have better flow.

So what about the high flow muffler options with each exhaust?

Diesel Mufflers

Adding an aftermarket performance muffler to your 4” or 5” exhaust system will not have much affect on EGT temps or power of your exhaust system. The muffler however will quieten down exhaust noise and sometimes drone compared to the straight pipe. It often comes down to only preference for the customer and doesn't benefit flow.

 

Aluminized or Stainless Steel?

Most aftermarket exhaust companies offer an aluminized steel or stainless steel exhaust system. Aluminized is an inexpensive option. It will have 3 layers of material. The innermost layer is the steel core. Outside of that is aluminum and the outermost layer is oxidized aluminum. The oxidized aluminum helps protect the inner layer from corrosion.

Stainless steel is iron that contains a minimum of 10.5% chromium. Stainless is the most expensive option but you will benefit from strength and longevity over the aluminized steel. Most customers that are in salty or harsh environments will opt for the stainless due to strength and corrosion resistance. Some companies offer long warranties with the stainless steel all the way to lifetime.

 

What about adding an exhaust tip to my system?

diesel exhaust tips

We offer many options for exhaust tips from stainless to powder coated and ranging in different sizes, shapes & designs depending on your preference. Length of the tip will depend on how far and how much room you have on your tail pipe. The majority of customers will opt for the 15” in length as this will take up most of the tail pipe length to maximize the visual impact of the tip.

Exhaust tips offer no performance gains but are only for bragging rights and aesthetics.