Don’t you want that extra horsepower that comes from straight piping your vehicle? Many truckers are desperate to get that additional horsepower but are unsure whether straight-piping a diesel truck is okay.
So now comes the moment of truth.
Yes, you can absolutely straight pipe your truck that has DEF. The diesel exhaust fluid (DEF) tank is located close to the fuel tank, which means it is not in the exhaust system. As a result, DEF will not interfere with straight-piping your truck.
Ready to straight pipe your vehicle? Don’t rush. Before you proceed, ensure you are well aware of its impacts of it. I will describe them in the next paragraph.

What Happens If You Straight Pipe Your Truck?
While straight piping has its perks in terms of performance, it also has downsides, such as generating a lot of noise. I will go over all of the pros and cons that can help you decide whether straight piping is a good idea.
1. Is It Good To Straight Pipe A Truck?
You will definitely gain some benefits from straightening the pipe on your truck. Have a look at them below.
- Improved Truck Health
Straight piping gets rid of diesel particulate filters as well as some inconvenient sensors such as the NOx sensor. In the long run, these components shorten the lifespan of your truck. Once you straight pipe your vehicle, you will notice an immediate improvement in throttle response and a healthier engine.
- Better Mileage
Do you find yourself spending too much on your truck’s fuel? Trust me; I know how costly that is. As surprising as it is, straight piping actually improves the mileage of your vehicle by a large margin.
So what are you waiting for? Straight pipe the truck and save yourself some bucks!
- Superior Driving Experience
It’s not like I hate modern diesel trucks, but their dull, slow and quiet nature doesn’t appeal to me at all. They are supposed to be kind of loud and responsive to make you feel like you are driving a genuine diesel-powered vehicle.
You can feel the pure thrill of riding a diesel engine again through straight piping.
- Better Performance
Straight piping is a must if you plan to transform your ride into a performance monster. There is no way that emissions devices like the DPF can ever allow a truck to produce 500 or 800 horsepower.
When you straight pipe, those devices are no longer attached. It gives you the opportunity to turn the vehicle into a performance truck.
2. How Bad Would It Be If You Straight-Piped A Truck?
Are straight pipes bad for your car? Yes, as I mentioned earlier, straight-piping your truck does come with some disadvantages. But how bad are they? Let’s find out.
- Against the Law
The law prohibits you from tampering with your vehicle’s emission system, meaning straight piping is illegal.
If you produce a significant amount of black smoke, you could be issued a ticket. Making loud noise through the exhaust can also get you fined for violating the noise protection law.
- Failed Emission
The chances of your ride passing emission tests are next to none when it’s straight piped. The lack of DPF eliminates any hope of passing emission tests.
Here is one more bit of bad news for you if you think you’ve heard enough.
A visual inspection will reveal that all of the exhaust filters are missing. You will be subjected to legal action, something you certainly do not want.
If you want to straight pipe and plan to do an emission as well, I might be able to help. Click here for details.
- Expensive
Buying an aftermarket exhaust is, in short, expensive. You will also need a substantial budget for a tuner. Exhaust systems do not work on trucks unless they have been tuned specifically for them.
In total, I am talking about a cost of well over a thousand dollars.
To Sum Up
The answer to the question, “can you straight pipe a diesel truck with DEF?” is yes, it is possible to straight pipe your truck even with DEF.
As I said earlier, the exhaust area gets entirely overhauled for the straight pipe to work. Due to DEF being far away from exhaust, you can run a straight pipe without DEF disrupting it.