Diesel Remapping or Diesel Tuning Box? What Should I Get?

What’s better between a tuning box and a remap for a diesel?

Browse online for even a few minutes, and the answer seemingly boils down to “tuning boxes are rubbish; invest in a remap. End of discussion.” But, did you really think anything involved with tuning a car was that simple?

Thankfully, modding your car isn’t that black and white. After all, tuning boxes still exist (and more importantly, are still used) for a reason, right?

So with that said, let’s take a look at everything tuning boxes and ECU remaps have to offer. You’ll even find if the online forums are legit, or if tuning boxes really aren’t so bad after all. So, let’s get right into it!

What is the Difference Between Tuning and Remapping?

Before we even get into any discussion about which is better, let’s begin by taking a look at how each of these forms of tuning work. After all, wouldn’t you want to know what’s actually happening under your hood before committing to one of these choices?

What is Remapping?

In short, remapping refers to tweaking your engine’s ECU to achieve better speed, performance, and fuel economy. In most cases, you’ll do this by hooking a computer to your On-board Diagnostic Port (OBD).

It’s a pretty quick process as well. With the help of a tuner, your car will achieve performance you never before thought possible. Equally impressive, it only takes a half hour or so to remap your ECU. You can’t go wrong there! If you’re looking for a bit more depth to this, we wrote a more in depth guide here.

For this one, you’ll probably need the help of a car tuner. Or maybe accidentally frying your ECU crispier than Gordon Ramsey fries his fish and chips sounds like a good idea to you. In that case, you can try remapping your ride yourself—just note that it probably won’t go so swimmingly if you’re new to modding cars.

In other words, play it safe and ask a diesel remapping specialist for help.

How Do Diesel Tuning Boxes Work?

Tuning boxes work quite a bit differently than remapping. Here, you won’t even need to touch your ECU. Instead, you’ll plug this box into your car between your sensors and actuators. And the end result is that it alters the information the ECU and engine communicate to each other.

To be exact, the ECU will read that there’s less fuel pressure than what’s actually in the car. So it responds accordingly by increasing the fuel pressure sent to the engine to make up for the difference. In other words, you get more diesel pumping through your car, which allows for more power.

Reasons for Remapping

Make sense so far? Great! Now let’s take a look at why you’d chose either form of tuning. So let’s kick this off by discussing the pros and cons of remapping!

Unchain the Beast Resting Within Your Diesel

As you may already know, carmakers will limit your vehicle’s performance with the ECU. So set it free of these shackles with a remap. Words can’t describe the feeling of driving your ultra-powered diesel the way the designers intended for it to be driven—free of performance restrictions!

More Speed, More Power, More…Everything

Bluntly put, even the best of tuning boxes won’t deliver on the performance that a remapped car provides. To give you an idea of how great your performance will grow, you can easily expect a boost of 30-40 bhp. That makes a pretty huge difference when it comes to pumping some extra speed out of your diesel ride. So, if you’re looking for the biggest performance boost, remapping is without a doubt the way to go. You’re not just rolling coal here—you’ll gain the horsepower to back it up!

Easier Drives and More Fuel Efficient

In short, your engine becomes more responsive. This means you won’t need to shift through your gears as often. Therefore, you can sit back and enjoy your drive for longer periods of time before needing to step on that clutch. Even better, this allows for some savings at the pump. So in the long term, ECU remapping will pay off with the dosh you save in gas.

Honest Numbers

With remapping, your injected quantity always reads at its true value. This also means that your car’s fuel economy numbers are exactly as they read as well. So if your car displays your MPG, that’s your true gas mileage. This differs from tuning boxes, where the fuel numbers are all around smudged.

What to Look Out For

It’s easy to say that remapping your ECU is a process that’s nothing short of epic. But even with that said, there are still a few things to be aware of before you fully commit:

More Expensive Than a Tuning Box…at Least at First.

A quality remap will cost more than a quality tuning box. But don’t let that worry you too much. When you’re not pushing your ride to its fullest with performance, remaps will allow for some better fuel economy. So after a few months, you’ll make up the difference at the gas pump.

Remapping Voids Your Warranty

Sadly, not all the best things in life are free. And for remapping, the price is your parts warranties. That’s not to say you can’t hide the remap. In most cases, you can reverse the process without anyone even noticing. But that’s still not a 100% full proof plan to prevent an OEM company from finding out you remapped at one point—it’s a rare occurrence, but it does happen. And it does cost you your warranty. So be aware of that if you’re still in the early stages of your warranty or you have a history of making full use of your car’s warranties.

Reasons to Buy a  Diesel Tuning Box

So, it’s no surprise that remapping is bloody fantastic, right? But it’s not for everyone. So in these cases, a tuning box is easily your next best option for your diesel ride. And, despite mainstream tuners hating on these devices, you’ll find they still offer plenty when it comes to optimising your drives.

They’re Cheap

As a whole, tuning boxes are a far more budget-friendly tuning option when it comes to pumping power out of your diesel. In fact, you can find quality tuning boxes for cheaper than £300. So you won’t need to worry about thinning your wallet too much if you’re looking to gain a bit more speed and power.

Great When You Don’t Have Easy Access to Your ECU

This one is especially true for older cars. In fact, OBD ports didn’t become a common feature until 2000. So, if your car is from before that year, then you’ll likely find tuning boxes to be an easier process for pumping some extra power out of your ride.

Easy to Do Yourself

Unlike remapping, inserting a tuning box in your diesel car is something that’s pretty easy—even for a beginning tuner. So with that said, it’s something you can do yourself. Moreover, most tuning boxes will even come with a detailed set of instructions to ensure you get it right on your first try. And in most cases, it’s really as easy as plugging the box into two ports—nothing more.

Of course, this means that removing the tuning box is something you can also do on your own. So if you ever need to use a warranty on a part or get your car serviced for any reason, removing the tuning box is as easy as installing it. In other words, it only takes a few minutes to restore your car to its original settings—no traces of its existence in the first place. Now that’s efficiency!

What to Look Out For With Tuning Boxes

No surprises here. Much like remapping, tuning boxes aren’t the end-all-be-all solution to tuning. So as you’d expect, you’ll want to be aware of a few things before you buy your tuning box.

Diesel Particulate Filter (DPF) Issues

Ever heard of a soot trap in your car? That’s your DPF. And like the name implies, this filter captures any excess soot and other garbage to reduce your diesel emissions.

If you remember from earlier, tuning boxes alter the signals of your fuel pressure. So then, it makes sense that over-fuelling is a common problem with tuning boxes. And as such, particles build up in the DPF far more frequently than they normally would. This means you’ll need to clean your filter more often. Also if you need to perform DPF forced regenerations to eliminate the excess soot, it becomes downright expensive as well. Therefore, be sure to give some extra attention to the DPF if you opt for a tuning box.

Performance Doesn’t Keep Up With Remapping

Here’s quite possibly the biggest con to a tuning box. Even the best of them won’t produce the same levels of performance and power that you’d get from an ECU remap.

Now, you’ll still get impressive performance boosts from a tuning box. With that in mind, the only real issue here is that you’re just not getting as much. To put it into practical terms, you can easily expect boosts of 30-40 bhp from a remap. But tuning boxes generally max out around 20 or so bhp. Of course, your car and your box will determine the exact numbers here. But don’t expect them to be as large as your friends who opted for a remap.

Your MPGs Aren’t as Great as They Appear

By this point, we all know the gist of how a tuning box works—the ECU and engine send false information regarding fuel pressure to each other. And as you might have guessed, this isn’t always great for your fuel economy.

The reason for this is that your injector pump takes on the bulk of the work now by providing even more pressure than before. However, the ECU isn’t appropriately reading these new higher fuel flows. As such, your fuel economy suffers.

Final Thoughts: What’s Better for your Diesel—Remapping Vs. Tuning Box

Time to wrap things up with one final, overarching question:

Should you remap your diesel or opt for a tuning box?

To answer this question, let’s consider what both of these formats have to offer. Remapping instantly boosts your diesel’s performance, grants it unrivalled speed, and even adds in some extra fuel economy as a nice bonus. So you’ll even see savings in the long run.

Meanwhile, tuning boxes are simply cheap and easy to install at the start. So they offer that quick little fix for upping your diesel’s power. But they will lack the same level of performance and fuel economy that a remap provides.

So it really comes down to this: Do you want a budget option? Or do you want the all-out no-holds-barred version of your diesel? If your answer is the latter option, then we’ve got just what you need.

When you’re ready to unleash all the hidden potential beyond anything you dreamt possible for your diesel, we’re here to help. So, to instantly gain access to speed and power like never before, contact Car Tune to book a quick consultation about remapping your diesel.