Can Turbochargers Deliver the Ultimate Performance Boost for Your Truck?

11th Feb 2025

Frustrated with sluggish acceleration? Spending too much time at the pump when you need to make your delivery? If you’re an owner-operator who is looking to boost driving performance, a semi-truck performance turbocharger might be just what you need.

Aftermarket performance turbochargers can dramatically enhance your truck’s torque and horsepower, thereby affecting your bottom line.

Truck performance directly impacts profitability, whether it’s maximizing mileage, delivering shipments on time, or minimizing fuel consumption.

Here’s How Turbochargers Boost On-the-Road Performance

Increases power and torque
Improves fuel efficiency
Reduces emissions
Altitude compensation

4 State Trucks Aftermarket Turbocharger Brands

We offer aftermarket replacement turbos from brands like BESTfit and AFTERMARKET.

These are designed to replace the widely-used OEM turbos made by Borg Warner for engines like:

Caterpillar
Detroit Diesel
Cummins

Let’s say that you’re driving a Kenworth T800. Then, it’s recommended that you get an aftermarket turbocharger replacement for the N14 engine or a turbo for the Cummins ISX engine.

Freightliner Cascadia has the Cummins NTC315 engine. We offer a replacement for it.

If you own a Peterbilt, you may need a turbocharger that complements the 3406E 475-550 HP CAT engine.

Some of our top-selling performance turbos are from brands like Bully Dog and Full Tilt Performance.

Turbos designed for the Cummins N14 engine:

Aftermarket Replacement Turbos vs Performance Upgrades

Aftermarket replacements are designed to serve as a cheaper alternative to an OEM turbo. Performance turbos offer an enhancement to the current setup.

Considerations Before Buying a New Performance Turbocharger

Turbocharger Stages

Turbocharger “stages” are general indicators used to estimate the range of horsepower that a turbo can deliver.

The stage number can differ heavily by manufacturer, since there’s no fixed industry standard.

Remember this: Higher stages do not guarantee an increase in horsepower.

The Turbo Stages and power output:

STAGE 1: OEM replacement grade or a mild upgrade.
STAGE 2: significant performance upgrades like a larger compressor wheel, improved turbocharger housing, or more efficient turbine wheel.
STAGE 3: Designed for max performance output; features larger components delivering more horsepower and torque gains, but lesser fuel efficiency and emission conservation.

Your Semi Truck’s Horsepower is determined by other factors:

Engine size and configuration
Your fuel system and how large it is
Engine tuning
Exhaust system, intake system, and intercoolers

Max Boost Pressure: What Your Engine Can Handle

The right turbocharger will need to be compatible with your engine. If it’s too large, it's sluggish on the bottom end. If it's too small, it won't gain the high speeds you need.

The AR (Air Ratio) Exhaust Housing

The Air ratio (AR) dictates how your turbocharger performs. It shows the ratio of how much air moves into the engine.

A low air ratio will lead to a quicker response time for acceleration gain. The higher the number, the slower the acceleration gain but the higher the maximum horsepower is on the highway.

Low to High AR Ratings Defined:

0.70 - 0.90 AR: lower ARs have quick spool-up and great low-end torque for good responsiveness, but caps out horsepower at higher RPMs.
0.90 - 1.10 AR: mid-range AR balances quick spool-up and high RPM horsepower; great for general-purpose long-haul driving
1.10 > AR: maximum top-end performance at high RPM, but spool-up is slow going.

The Intake Wheel

This is the compressor wheel of the turbocharger. It spins and draws air into it, compressing it, and then forcing it into the engine to burn more fuel.

The diameter size directly impacts how much air the turbocharger can take in.

Larger MM diameter = more air, burns more fuel, and achieves higher horsepower levels.

Smaller MM diameter = less oxygen to burn fuel, and lower max horsepower.

Intake Diameter Sizes:

68MM - 76MM: OEM replacements and slight power increases.
76MM - 85MM: noticeably higher boost in power.
85MM - 100MM: max power output for heavy modifications which are rare to see.

Turbo Ball Bearings vs Journal Bearings

Bearings control the turbine rotation speed from the input of exhaust gases.

Ball bearings: faster spool-up, less friction, responsive
Journal bearings: simple design, slower spool-up, durable, more cost-effective.

Why Turbochargers Aren’t the End-All-Be-All Performance Upgrade

If you want to truly boost your truck’s performance, look at your whole system, not just the turbocharger.

A turbocharger is just one part of how your truck achieves higher torque and RPM. Upgrading your exhaust, intake manifold, and fuel system can go a long way.

Besides that, you’ll need to properly tune your truck’s engine to achieve the full potential of your turbocharger.

This can get really technical, from ECU reprogramming to upgrading various components like your intercooler.

Advice: contact a seasoned diesel truck mechanic and get more info from your manufacturer.

Turbochargers vs Superchargers: The Difference Explained

Sometimes people get these two parts confused.

Supercharger = gear-driven (by the crankshaft)
Turbocharger = exhaust-driven

A supercharger is directly driven by the engine's crankshaft via a belt to steal power from the engine to compress air and provide more power. Semi trucks no longer use these. The old models used to.

A turbocharger is more environmentally friendly but takes a bit more time since it needs to spool exhaust fume waste and transfer it into more power for the engine to burn fuel.

Which one is better for your truck?

Superchargers aren't really added to semi trucks anymore. But if you're looking to really customize and "trick-out" your truck - you could use one.

Turbochargers are the industry-wide standard, and the better option.

Turbochargers work to increase power gradually, spooling excess exhaust fumes, while offering much better fuel economy for long-haul truck driving.

How Turbochargers Work: The Breakdown

Diesel engines rely on oxygen intake to burn more fuel. Turbochargers increase the amount of air, via the excess exhaust fumes, to help the engine burn more fuel.

So in other words, a turbocharger is a smart way to recycle the energy from the engine's exhaust to force more air into the engine, giving the truck extra power and making it more fuel efficient.

Putting it simply:

The engine burns fuel and creates hot exhaust fumes that get released through exhaust pipes.
The turbocharger, a special-looking windmill gets hooked up to the exhaust pipe to catch those exhaust fumes before they exit the pipes
The force of the exhaust pushes a wheel inside of the turbo to spin fast, just like a windmill
This spinning wheel connects to another wheel that’s on the other side of the turbocharger which acts like a powerful fan
This fan will suction the fresh, oxygen-rich air and push it into the engine so as to give it more fuel to burn and extra energy to use.

Longevity of Aftermarket Turbochargers

Depending on maintenance and driving habits, turbochargers can last between 500,000 and 700,000 miles or more.

The ROI of Aftermarket Semi Truck Turbochargers

Is it worth the investment?

Check for yourself.

Compare the upfront cost to the other savings you’re likely to have: like fuel savings, improved payload capacity, and road speed.

A turbocharged Freightliner Cascadia owner reported a 12% fuel efficiency boost after upgrading. That’s saving around $6,000 per year in diesel costs—more than paying off the turbocharger investment in just one year.

Types of Turbochargers Explained

They come in larger and smaller sizes.

Larger turbos: top-end power but can lag, taking more time to generate energy.
Smaller turbos: boast a faster response time and balanced performance.

Some aftermarket turbochargers are non-wastegated, meaning they can’t divert excess exhaust fumes away from the turbine. For these, you may want to buy a wastegate as well.

Turbochargers are generally classed based on how they work to move exhaust gas.

Fixed Geometry Turbochargers (FGTs)

All exhaust flows through a fixed path to the turbine wheel, making it a smaller and simpler design. It’s ideal for engines running at a constant speed (rarely ever used in vehicles).

Wastegate Turbochargers

A valve lets some exhaust gas bypass the turbine, preventing "overboost" - meaning, it's generating way more air pressure than what's safe for the engine.

This type of turbo is ideal for consistent performance at various engine speeds, and gives better acceleration at low speeds.

Variable Geometry Turbochargers (VGTs)

The exhaust passage size changes to control gas pressure and flow to the turbine, offering great optimization across various speeds and payloads.

Axial Flow Turbocharger

Axial flow turbochargers essentially refer to the type of fan blade arrangement that rotates alongside the shaft pushing air parallel to it into the

Compound Turbocharger (Sequential) Engines

This one is commonly mistaken for a “parallel” or “twin turbocharger.”

A compound turbocharger has two differently sized turbos that operate in a series, the first being smaller and the second being larger. The smaller turbo feeds air into the larger one which “compounds” the boost, adding even more crankshaft power.

A Parallel or twin turbocharger is different. It has two similarly sized, distinct turbos that each work independently to feed more power to the engine.

That’s the main difference. One engages in turbo-compounding (TC) and the other doesn’t.

Turbo-compounding is when the exhaust gas from the first small turbocharger is moved to the secondary turbine that captures the additional energy of the exhaust’s air.

This second turbo then transfers the energy directly into the crankshaft through a complicated gear system.

Viola. And with that, you now have more low-end power and better fuel efficiency for your truck.

Semi Truck Engines that Use a Single Turbocharger

The majority of class 8 commercial semi trucks use a single turbo.

The Cummins X15 Engine:

Peterbilt 389, 367, 579, 520, and 567
Kenworth T680, T880, W900, W900L
Freightliner Cascadia, W122SD and 114SD

Detroit Diesel DD15:

Common in many Freightliner and Western Star models
Uses a single turbocharger

PACCAR MX-13: Commonly made for almost all Kenworth and Peterbilt models.

Older Caterpillar C15 (pre-ACERT):

Before Caterpillar introduced ACERT technology, the C15 engine had a single turbo application.

Semi Truck Engines that Use a Dual or Twin Turbocharger

Cummins
Volvo

The Components of a Turbocharger Explained

Cummins is the lead manufacturer of semi truck turbochargers. Depending on the type of turbocharger, it’s a fairly complex mechanism.

Here are the core components:

Compressor Wheel: compresses intake air to increase oxygen density for improved combustion
Turbine Wheel: moved by exhaust gases that spin the shaft to power the compressor
Bearing System: houses the bearings, lubrication system, and seals to prevent leaks
Compressor Housing: designed to suction in, compress, and direct air out through an outlet
Exhaust Gas Outlet & Inlet: the inlet is where hot exhaust gases enter the turbocharger to spin the turbine wheel and the outlet is where gas exists from the turbocharger
Compressed Air Outlet: the place where the pressurized air moves into the engine’s intake manifold

Signs that Your Truck's Turbocharger is Damaged

Truck moves slowly uphill
Excessive smoke coming from exhaust pipe
Whining or whistling noise from the engine
“Check engine” light is on

How to Maintain Your Turbocharger for Years to Come

If you're driving a newer model, it has an OEM turbocharger. So, unless you want to dish out serious wads of cash for a replacement, consider keeping your current one in mint condition.

A replacement turbocharger can cost $2,000 or more!

Here's the best way to preserve your turbo:

Regular oil changes
Swap out the air filter periodically
Monitor for signs of wear and tear on components
Maintain proper cooling to avoid overheating the components

Aftermarket Turbocharger FAQs

Do turbochargers wear out your engine faster?

If properly maintained, turbos can extend the engine’s lifespan.

If turbos need time to spool up, doesn't that lag make them inefficient?

Modern turbochargers, like VGTs, minimize the lag time significantly.

Can I add a turbocharger to any semi-truck engine?

Not all engines are designed for turbochargers. Check compatibility with your engine model and talk to your manufacturer before upgrading.

Will a turbo make my truck faster?

Yes, but speed gains depend on the turbo size, tuning, and supporting modifications like intercoolers and exhaust upgrades.

How much fuel savings can I expect after installing a turbo?

There’s no exact number.

Are there tax incentives for installing a more fuel-efficient turbo?

Some states offer incentives for fuel-efficient upgrades. Check local regulations or talk to a fleet consultant.

Do I need a new exhaust system if I install a turbocharger?

Not really; a high-flow exhaust system can help elevate the turbo’s performance.

How often should I replace my turbocharger?

Rarely. They can last between 500,000 and 700,000 miles.

How do I know if my turbo needs replacing?

Excessive exhaust smoke, loss of power, increased fuel consumption, and a loud whistling noise from the engine.

Can I add a turbo to an older truck engine?

Some older engines can support aftermarket turbochargers, but they may require modifications to work efficiently.

Will a turbocharger void my truck’s warranty?

It depends on the manufacturer’s policies. Always check with your dealer before installing aftermarket parts.

How do I choose between a small and large turbo?

Smaller turbos spool up faster for more low-end torque; larger turbos spool slower and have more top-end power.

Purchase Your Next Performance Turbocharger from 4 State Trucks

Don’t let slow acceleration eat away at your profits! If you need some extra information about our lineup of turbochargers and related products, give our team a call during office hours and we’ll be happy to help!