Auto mechanic tuning an ECU using a computer

Chip Tuning – Risks and Rewards of ECU Remapping

Everyone with even a passing interest in cars has heard of chip tuning. As the story goes, a magical mechanical man turns up with his secret software, plugs it into your engine, and BOOM: Your car’s a lean, mean, street racing machine! Yes, in the best-case scenario, this is exactly what happens – done properly, an ECU remap can safely boost your car’s performance and even improve fuel efficiency.

However, as with anything software-related, there is an equal opportunity for an absolute nightmare if done badly, with poor performance, or even total and utter engine failure.

But what is ECU remapping, and what exactly does it do for your vehicle? We explain the concept, and its risks and rewards, below.

Automotive engine control unit ECU

What is an ECU?

As cars have progressed, so have the technologies that manage them. In previous decades, cars were almost purely mechanical (with the exception of the starter motors, headlights and so on), but today most of a modern production car’s functions are controlled by ECUs.

An ECU, or electronic control unit, is a ‘chip’ with software installed with default settings for those functions. A car might have up to 50 or more ECUs, which handle things like the driver interface, door locking systems, airbag systems and so on.

However, the ECU we’re specifically talking about here is the Engine Control Unit which controls things like fuel flow, gear ratios, engine speed, variable valve timing and so on.

What is ECU Remapping?

When a car rolls off the production line, its Engine Control Unit’s software is set to a default that works anywhere in the world, taking into account factors like different climates, road conditions, geographical conditions, varying fuel qualities and so on.

While these default settings might be the best generic setting for your vehicle overall, they might not be the most efficient settings for your particular requirements. For example, if you want more performance, an ECU remap can change the gear ratios, air/fuel ratios and fuel flow of your car’s powertrain to boost power, usually at a sacrifice of fuel efficiency. If you have replaced some other parts in favor of high-performance parts on your vehicle, like a performance exhaust, for example, you might also want to have your ECU tuned to fit the new mods. Any performance add-on will require a different ECU mapping to get the most out of it.

On the other hand, if your vehicle is a working vehicle such as a van, truck or company fleet car that does a lot of miles, you might want to remap the ECU to boost fuel efficiency at a slight cost of performance.

What are the Rewards?

Well, as any gearhead would say, power is its own reward, and sure, if your Honda Civic suddenly shifts like hot shit off a shovel without any other modifications for a relatively inexpensive remap, then you’d think that was a pretty good deal. Also, if your car’s top speed is electronically limited, you can have that removed as well.

And for a workhorse, if you’re suddenly saving hundreds of dollars a year on fuel, an initial investment of a couple of hundred bucks is a wise move.

automotive problem diagnosis

What are the Risks?

The first thing you should bear in mind is that if a car’s top speed is limited, this is usually for a very good reason – you don’t want to find out the hard way that your car suddenly turns into a kite at speeds in excess of 155mph. You should also bear in mind that the car’s standard brakes, tires and suspension are all matched to the car’s power output at production, and won’t be able to safely deal with any significant boost in power and speed. Again, you don’t want to find this out the hard way at high speeds.

The second main thing you should bear in mind is that, as with any software, there are pirates. Any cowboy with a laptop and the right connections can lay his hands on the software and the right plugs for your car’s serial port, and turn up on your driveway promising big performance gains for peanuts, but his software might be outdated, hacked or cloned.

You wouldn’t let some guy from Craigslist promising big improvements on performance come and install a shady copy of OS X on your $2000 MacBook, would you? And yet this is what hundreds of people have done to their $20,000 cars each year.

In the case of a bad remap, the best-case scenario is that you notice strange, inconsistent behavior from your vehicle, and you end up having to take it to a reputable ECU Remapping center and paying to have it redone properly. A worse scenario is that the dodgy software damages your ECU, causing total engine shutdown, and requiring you to fork out a couple of grand for a new ECU.

In the very worst case, the shady remap is entirely unsuitable for your powertrain, causing irreparable damage to your engine or transmission, and costing you many thousands of dollars.

How to Avoid the Risks

Predictably, the advice is: Steer clear of the cowboys. Go with reputable, well-established tuning companies with a track record. They might be more expensive, but this is for a reason – they use well-trained technicians, and their hardware and software are licensed and up-to-date.

Things you should also look out for are whether they are covered by insurance and if they offer a warranty, both of which should be a ‘yes’.

An initial investment of an extra couple of hundred dollars could save you thousands in the long run, so don’t take risks with your ride.

Check out and get a safe performance tuning chip for your vehicle.

About Nishal Singh

Car enthusiast since before I could drive.


  1. Avatar

    I live in Thailand… but still have a question as I follow blogs etc.
    I have a subaru forester 2.0i P
    I can choose between ECU remapping and a plug and play solution.
    My question is if I can do both… first the remap and add 20 HP and then the chip for another 20 HP or doesn’t it work that way???

    Please advise,

    • Avatar

      This likely would not work through just computer tuning. Both of the solutions you have described would yield similar result, without significant modifications to the car itself to yield the extra power.

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