Tuner vs Stealth Module: Are they the same?

Tuner vs Stealth Module: Are they the same?

As we’re sure you’ve noticed, diesel trucks appear to be significantly faster and more powerful than before. For example, all three major brands offer roughly 1,000 lbs./ft. of torque from the factory. Regardless of the advertised high peak power figures, a large portion of new diesel owners are left unsatisfied with their new purchase.

Don’t get us wrong; these trucks come from the factory with plenty of power to get the job done. The issue is that these trucks feel awkward - as if you’re always lugging outside of its power curve. Perhaps that has to do with the fact that dyno figures represent wide open throttle situations which are not typical or realistic for your daily driver, especially when mileage is a concern.

This is probably why you landed here - wondering if you should go the old route of flashing the ECM (Engine Control Module) and sacrificing your warranty or “settle” for a warranty-friendly solution. Stealth Modules are a very popular option for the silent majority of diesel owners out there, but they are not for everyone.

Our goal today is to help you understand the difference between a flash tuner and an inline module so you can decide which option is best for you. Read on to learn the ins and outs of tuner vs module.


If you’re like most new diesel pickup owners we speak to, this is not your first rodeo. You’ve had one or more stinky, smokey, unreliable, and heavily modified 2000’s pickup.

You’ve been down the long slippery slope of buying performance piping, exhaust, studs, turbos, transmission rebuilds, etc. After years of exploring that route and of experiencing the end result, you’re hoping for a satisfying yet less invasive option.

Tuners plug into the OBD II (Onboard Diagnostics Systems) port and flash the ECM. They are great for big top-end power and exploring the absolute limit of a truck’s potential. Wide open throttle dyno figures and ¼ mile times will be more impressive compared to a module.

This option is usually complemented with a plethora of expensive supporting modifications and requires gauges to monitor drivetrain vitals. Having full control over the ECM is important when squeezing power out of larger injectors, turbo, manifolds, exhaust, intercooler, etc. Exhaust gas, coolant, oil, and transmission temperature limits can be raised to avoid pre programmed electronic safety limitations.

Since this approach at power is better suited for increasing power on top of the peak, it is uncommon for tuners to amplify the throttle sensitivity to give the impression of more power down low. Stop light to stop light, playing around can be a blast. Wide open throttle peak power gains are typically 30-150 hp and 50-300+ lbs./ft. of torque.

Stealth Modules

Modules intercept ECM reference signals by plugging inline under the hood with simple factory style connectors. These are great for improving power where it is lacking. Instead of lugging around, waiting for the boost to hit.

Your truck will be happy getting the job done in a much broader RPM range. Modules will not make you blow smoke, do wheelies, or apply throttle manipulation like a tuner.

Instead, you will have smooth predictable power delivery that allows you to hold higher gears and keep your RPMs down. The 2-stroke style power curve, which has a lot of lag followed by a sudden surge, will be replaced with freight-train-feeling, 4-stroke style torque power delivery.

Working outside the ECM with a module means factory safety parameters remain in place. No other modification is required or even recommended. Wide open throttle peak power gains are typically 30-60 hp and 50-100+ lbs./ft. of torque.

What About Mileage?

Mileage is a hot subject in the diesel industry. There is no way around it. If you plan on using horsepower to get the job done, you need to feed the horses.
Gasoline is significantly more combustible at a rest than diesel. Have you ever tried to light a puddle of diesel with a cigarette lighter? Imagine the potential that can be squeezed out of every drop of diesel if it is properly atomized out of the tip of an injector into a combustion chamber with a piston compressing it until it explodes.

Stealth Modules’ approach to power, combined with responsible driving habits, often result in a mileage improvement. It is hard to deny, considering our feedback is littered with subtle flexes. There are far too many factors involved for us to get involved in guaranteeing mileage.

We hope to sell modules based on power improvements instead. If you’re using your highly addictive and smile-inducing power to accelerate faster; mileage is not a priority and gains shouldn’t be expected. What we find is that, once the initial phase of pure bliss and power intoxication is attained, some customers do a great job of using throttle discipline and patience to take advantage of the power on demand to get down the road with less effort.

So.. Tuner or Stealth Module?

Now that you know more about tuner vs module you can wrap your mind around the benefits of our module, and it will be a no-brainer. Are you interested in more power where you need it without spending thousands of dollars?

Just remove it before service, and it does not leave a trace in the truck’s computer? Can you install it yourself with factory style connectors? Yes.

You might ask yourself, “Well, why doesn’t the factory just do this already?” It’s simple. They do. The difference is that our modules work by bringing the fuel pressure up earlier and boosting on quicker. That is how manufacturers are able to squeeze out more power year after year.

Unlocking the performance your truck should have come with from the factory is as simple as ordering a Stealth Module with free shipping** and taking a few minutes to install the unit yourself in your driveway. Unplug a couple sensors, plug our module inline, and drive off enjoying the same performance you see our customers bragging about.

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