Login
My Account
My Cart
The site navigation utilizes arrow, enter, escape, and space bar key commands. Left and right arrows move across top level links and expand / close menus in sub levels. Up and Down arrows will open main level menus and toggle through sub tier links. Enter and space open menus and escape closes them as well. Tab will move on to the next part of the site rather than go through menu items.
Enter your truck info so we can recommend the right products for you.
Can't find it? Call us at 859-737-4966 for free advice.
Menu
Banners
Decals
Hats
Hoodies
Shirts
Tank Tops
Show your support with a Thoroughbred Diesel t-shirt, sweatshirt, or sticker decal.
Fuel prices are something every diesel truck owner thinks about. When diesel prices climb, the question becomes pretty simple: What can I do to improve my diesel fuel economy and spend less money at the pump?
There are a lot of things inside the diesel performance world that can help. But before we start throwing parts at a truck, we need to talk about the bigger picture.
The word I want you to remember is efficiency.
If we can make the truck more efficient, better diesel fuel economy should naturally follow.
There are three main areas I want to cover:
General maintenance
Tuning
Performance and upgraded hard parts
All three of these work together. You can’t neglect one and expect the other two to magically make up for it.
Before you spend money on a tuner, injectors, a turbo, or anything else, there are several things you can do that cost little or nothing.
This gets talked about constantly, and it should, because tire pressure is one of the easiest things you can address.
If you have a low tire that you’ve been fighting for months and you keep putting off getting it fixed, get it taken care of.
Every time that tire gets low, it creates more rolling resistance. More resistance means the truck has to work harder, and that costs you fuel.
If you’re running the stock tire size and configuration, look at the recommended tire pressures inside the door jamb. The manufacturer has already determined an appropriate pressure for the truck and its normal loading.
Get the tires right and keep them right.
Think about everything you carry around in your truck.
If you’ve got a cord of firewood in the bed, a slide-in camper you haven’t taken out, a toolbox full of tools you don’t need for your daily commute, or a back seat full of hunting gear from three seasons ago, all of that is weight.
And weight costs you efficiency.
Go through the truck and ask yourself what actually needs to be there.
You might be surprised how much weight you can remove.
And while we’re at it, wash the truck.
If you’ve got a bunch of mud packed underneath it, you could be carrying around a surprising amount of extra weight. Clean it up.
Little changes might not seem important on one trip, but over months and years they can make a difference.
Aerodynamics matter too.
If you have something hanging off the truck that catches a bunch of air, it’s creating drag.
Things like bed covers can change how air moves across the truck. The point isn’t that everybody needs to run out and buy one specific product. The point is to look at your truck and think about anything that is unnecessarily creating resistance.
Again, we’re trying to make the truck more efficient.
One maintenance item people sometimes overlook is alignment.
If you’ve recently replaced tires, steering parts, or suspension components, make sure the truck is aligned properly.
A truck that is fighting itself going down the road is wasting energy.
That also brings us to worn steering and suspension components.
If your tie rods are worn out or your ball joints are bad, number one, you might not be able to properly align the truck.
Number two, you’re probably going to eat tires.
And number three, you could be creating additional drag that hurts efficiency.
The same idea applies to other components.
If you’ve got a vibration at 55 mph, don’t just ignore it for the next year. Check the truck. Look at the U-joints and driveline components.
A failing component can create drag, reduce efficiency, and eventually cause a bigger repair bill.
Basic maintenance matters if your goal is better diesel fuel economy.
Change your filters.
Keep your fuel filters serviced. You want the fuel system working the way it was designed to work without unnecessarily restricting it or forcing the system to work harder than it should.
Stay current on your oil changes.
Look at the entire operating system of the truck and think about filters or service items you might normally forget.
A lot of diesel owners don’t think about their positive crankcase ventilation filter until there’s a problem.
Those filters have service intervals too.
If crankcase gases aren’t being managed properly, you can start creating additional problems inside the engine and emissions system.
You can end up putting an oily mess back into systems like the EGR and eventually creating more buildup.
Stay on top of the crankcase filtration system.
Even something as simple as the cabin air filter is worth maintaining. If your HVAC system has to work harder because airflow is restricted, that’s another system on the truck using energy unnecessarily.
The larger point is simple:
A well-maintained truck gives everything else the opportunity to work correctly.
Let’s go back to something that is completely free.
Your driving style has a huge effect on your diesel fuel economy.
A lot of people don’t like talking about this because it’s easier to talk about parts.
But your right foot directly affects fuel consumption.
If you drive everywhere like you’re qualifying for the Indy 500, you’re going to burn more fuel.
We talk about driving on offense versus driving on defense.
If you’re constantly accelerating hard, braking hard, and getting right back into the throttle, the truck is going to use more fuel.
Try backing off.
Watch how the truck responds.
You may find that simply changing your driving habits puts money back in your pocket.
Sometimes the cheapest modification you can make is just not driving like an idiot.
Now let’s talk about tuning.
Modern diesel trucks have incredibly complex operating systems. Tuning companies are working with a huge number of tables and parameters involving the engine, transmission, emissions systems, fueling, airflow, and much more.
One misconception I hear from diesel owners is that adding horsepower automatically means you’re dumping a bunch more fuel into the engine.
That’s not necessarily how it works.
There is obviously a point where how you use the additional power matters. Your right foot is still going to have a lot to say about fuel economy.
But a good tune or inline module is designed to work with the operating system of the truck.
The goal is to improve the way the truck operates.
And when you improve efficiency, you can sometimes produce more power while also putting the truck in a better operating range.
That can translate into improved diesel fuel economy depending on the truck, the tune, the setup, and how you drive it.
But there is an important catch.
Tuning can’t do what it is designed to do if the truck isn’t maintained.
If you haven’t changed the oil in two years and you don’t know where the fuel filter is, you can’t expect to bolt a tuner onto the truck and suddenly have everything work perfectly.
Maintenance gives tuning the opportunity to work correctly.
That relationship matters.
If you’re considering tuning, I like the idea of using a device that also gives you monitoring capabilities.
If the tuning option you want doesn’t provide monitoring, consider adding a separate monitor.
Why?
Because monitoring teaches you what your truck is doing.
Many devices can display real-time miles per gallon along with other important engine parameters.
Once you start watching real-time fuel economy, you can see exactly how your driving style affects the truck.
You start learning things like:
What happens when you accelerate harder?
What happens at different highway speeds?
What happens when towing?
What happens when you back out of the throttle?
That information can help you adjust your driving style and get better efficiency without changing another part on the truck.
Do your research when choosing tuning for your platform too.
Different companies have different strengths, and some have more experience with certain truck platforms than others.
Look for feedback from people running a setup similar to yours.
If fuel economy is one of your goals, find out what people with similar trucks and modifications are actually experiencing.
You also need to understand what you’re driving.
You are not going to magically gain five miles per gallon by putting a tuner on a truck with a huge lift and enormous tires.
It’s just not going to happen.
If you’ve built a show truck with a big lift, big tires, and a lot of additional weight and wind resistance, that setup has consequences.
There’s nothing wrong with that if that’s what you want.
Just understand that you’re working against fuel economy.
Your modifications need to match your goals.
The third area is performance and upgraded hard parts.
There’s quite a bit that goes into this because every diesel platform is different.
The main thing I want you to think about is airflow efficiency.
That applies to both the intake side and the exhaust side.
If the engine can move air more efficiently, the entire system has the potential to work better.
One example is intercooler piping.
There are diesel trucks where the factory intercooler piping has restrictions created because of packaging, clearance, transitions, or the original design.
Aftermarket manufacturers may offer upgraded piping designed to reduce those restrictions and improve airflow from the intercooler into the engine.
The same idea can apply to other parts of the intake system.
Look at your specific platform.
Ask:
Are there known airflow restrictions on this truck?
There is a lot of information available for most diesel platforms.
The exhaust side can have similar issues.
There have been diesel platforms with factory exhaust manifold designs that include restrictions created for clearance.
Aftermarket manufacturers have addressed some of those restrictions with redesigned manifolds that improve flow.
That can be a worthwhile upgrade on the right truck.
Again, this is platform-specific.
The point isn’t to replace every part on the truck.
The point is to identify where the factory system may have an inefficiency and decide whether correcting it makes sense for your setup.
Turbo sizing matters.
If you have a turbo that is too large for the way you use the truck, it may not operate in the most efficient range for your application.
Maybe your original goal was maximum horsepower.
Now your priorities have changed.
Maybe the truck is a daily driver.
Maybe you’re towing more.
Maybe you’ve got a family now and you’re more interested in drivability and fuel economy than chasing a horsepower number.
There is nothing wrong with changing the setup.
Talk to somebody who understands turbo sizing and the way you actually use your truck.
The biggest turbo isn’t always the best turbo.
The best setup is the one that matches what you’re trying to accomplish.
The same idea applies to injectors.
If you installed injectors that are much larger than what the truck needs, they may not be ideal for your current goals.
There are also upgraded injectors designed with improved fuel atomization and efficiency in mind.
Some manufacturers even market certain injectors specifically as economy injectors.
The idea is that improving atomization and combustion efficiency can give you a performance improvement while potentially helping fuel economy.
Do your homework.
Look at the data from the manufacturer.
Talk to people running similar setups.
Most importantly, make sure the injector matches the rest of the truck.
The fuel system shouldn’t have to work harder than necessary.
If your truck uses a lift pump, consider the condition of that pump.
If the original lift pump has a lot of miles on it, replacing or upgrading it may make sense depending on the platform.
There are also diesel platforms that did not originally use a traditional lift pump setup where adding one can improve fuel supply to the high-pressure side of the system.
The low-pressure side and high-pressure side of the injection system have to work together.
If you can improve the efficiency and reliability of the fuel supply side, you’re helping the entire fuel system operate the way it should.
Gearing is another thing to think about, especially if you have changed tire size.
When you install much larger tires without making the appropriate changes elsewhere, you change the effective gear ratio of the truck.
Depending on your setup, changing gearing may help get the engine back into a more appropriate RPM range.
The goal is to get the entire combination working together efficiently.
Tire size, gearing, engine speed, transmission behavior, and driving conditions all play a part.
If you have a later-model diesel truck with emissions equipment, the condition of those systems matters too.
If the truck has a lot of miles on it, especially if you do a lot of in-town or short-trip driving, components like the EGR and DPF may not be operating as efficiently as they once did.
If an EGR component is worn or no longer functioning correctly, replacing it with a new unit can restore proper operation.
DPF service is also something worth considering.
There are diesel and fuel shops around the country that have invested in DPF cleaning equipment.
If you’re noticing more frequent regeneration events, increasing soot levels, or other signs that the DPF isn’t operating the way it used to, talk to a qualified shop.
Ask what cleaning or service options are available for your truck.
The EGR, DPF, and crankcase ventilation systems all work together.
When those systems become restricted or lose efficiency, they can hurt the overall efficiency of the truck.
If you own a later-model truck and mostly drive short distances around town, give the truck an opportunity to reach normal operating temperature and spend some time at highway speeds when appropriate.
These systems need heat and airflow to operate correctly.
Getting the truck out on the interstate periodically and letting everything come up to temperature can help the emissions system complete the processes it was designed to perform.
One thing I see all the time is somebody who started modifying a truck with one goal and now has a completely different goal.
Maybe you originally wanted a high-horsepower truck.
Now you’re driving it every day.
You’ve got a family.
You tow with it.
Fuel costs matter more than they used to.
There’s nothing wrong with changing the truck.
If you have a setup that no longer makes sense for how you use it, change it.
Maybe that means going to a smaller turbo.
Maybe it means changing injectors.
Maybe it means correcting the gearing.
Maybe it means taking some of the lift out of the truck.
You can still have a fun diesel truck while setting it up to be more efficient.
If your goal is better diesel fuel economy, keep one thing in mind:
Your main goal is fuel economy, but the way you get there is by improving the efficiency of the truck.
Maintenance, tuning, and performance upgrades all have to work together.
Start with maintenance.
Keep the filters changed. Keep the truck aligned. Fix worn components. Maintain proper tire pressure. Pay attention to the emissions system. And think about how you drive.
Then look at tuning.
Choose something that makes sense for your truck, your platform, and your goals. If possible, use monitoring to learn what the truck is doing and how your driving habits affect fuel economy.
Finally, look at the hard parts.
Are there airflow restrictions?
Is the turbo sized correctly?
Are the injectors appropriate for the setup?
Is the fuel system working efficiently?
Does the gearing match the tire size?
Study your platform and identify the inefficiencies that actually apply to your truck instead of just buying parts because somebody said they add horsepower.
When the hard parts are right, the tuning can work better.
When the maintenance is right, both the tuning and the upgraded parts have the opportunity to do their jobs.
That’s how the whole combination comes together.
If you have questions about your truck, your current setup, or what you can do to improve diesel fuel economy, give us a call at Thoroughbred Diesel. We’ll be glad to talk through your setup and help you figure out what makes sense.