ECU Remapping explained

ECU Remapping explained



With so many options out there these days when it comes to extracting extra performance from your vehicle it is hard to know the difference between all of the options available, with plug-in boxes available on ebay for as little as £10 which claim up to 40% more power!

In this article we will concentrate on ECU remapping, the differences between the different types of remaps available, and why you should be very careful before handing over any of your hard earned cash. We also have a recent example of a customer that came to us after opting for a cheap 'mobile' option and the results.

Rather than telling you all of the reasons why these cheap, risky options are best avoided, we will tell you the methods we use and why we use them to ensure perfect power delivery and reliability.


Pre tuning checks

One of the most important stages is checking the current condition of the vehicle. To do this we will carry out a visual inspection and a health check on our linked 4x4 rolling road (dyno). This means that we are able to mechanically link the front and rear wheel speed so all 4 wheels are turning, as they would on the road and then measure the vehicles standard power and torque in a safe, temperature controlled environment as well as plot a power curve. This will show up any problems with the vehicles engine or emisson systems. If a problem is found it will need to be rectified before any tuning takes place.



If all is well with the Pre tuning checks we will then look at the data that we have managed to capture from the vehicles ECU while the tests were being performed. This can include critical information regarding boost pressures, ignition timing, fuel pressure, load values, throttle plate position, fuel trims, Air-Fuel ratios, temperatures and many more. This data is all then evaluated by both our dyno operator and software calibrator. Again, if any problems are found they will need to be rectified before any tuning takes place, tuning a vehicle that is not 100% healthy can cause even more problems in the future.


Software Calibration (remapping)

Once the Pre tuning checks and Datalogging are complete, we will read the data contained within your ECU (the stock MAP) and our software calibrator will identify the various different tables that require adjustment and then create a 'base map' based on the knowlege and experience we have with that engine and ecu. This is then written or 'flashed' back to the ECU.


Dyno testing

Now that we have lots of data of how the vehcile was performing before tuning, we will test our base map, and then view the differences to both power and torque output, and view the datalogs to see if the changes we have made have had the desired effect, and ensure that the various parameters we have changed are within safe levels. Its rare that the base map is perfect, so the process of dyno testing, datalogging, calibration and more testing is carried out many times until the performance gains and data is perfect. below is an example of how changes to a map can look, and the power gained between changes


As you can see, the power curve is very different between the 3 map changes (orange, blue and green power curves) compared to the standard curve in red. This is a great example of why the back to back testing and tuning is critical to achieve a great end result. The customer is then given a copy of the power curves, a tuning certificate and warranty allong with a copy of their VAT reciept.


The difference

Now that you have read how it should be done, lets take a look at what happens when its not done properly. This example shows why the 'man in a van' armed with a laptop, mobile phone and access to cheap map files really is a false economy, it may be cheap but its also probably terrible quality. This customer booked in with us for a dyno test, he had paid for a mobile remap on his VW T5 Transporter 2.0l 140bhp van but it really didnt match his expectaions and wanted to check if the remap he had paid for was delivering what it promised. Once tested it was clear that something was not right, producing just 16bhp and 40nm more than standard, far from the gains he was promised, so we returned the van to a factory spec stock file and measured the difference, the results are below:


As you can see, the van had gained a little power and torque in the higher and lower rpm range, but virtually nothing in the mid-range. Dissapointed with this, the customer gave us the go-ahead to remap it with our CustomPro ECU software and the results speak for themselves, below graphs show the standard power (red), the mobile remap (blue) and our CustomPro remap (green) with power and torque on seperate graphs to make it easier to see the differences, which are clear to see. Much smoother power delivery and more power and torque accross the entire rpm range.



The above is just one example of many that we see on a weekly basis, we have invested hundreds of thousands of pounds over the years on equipment to be able to tune modern vehicles correctly and safetly, the question to ask yourself when considering a cheap remap is wether or not a mobile remap from a tuner with no dyno equipment, no datalogging tools, no real tuning experience or knowledge can safetly remap your car at the side of the road, and will the results be what they promise? sadly, the answer is often no. 


We have ECU remaps available from just £199 for more info please give us a call on 01915402048 

Or use this link to see what we can do for your vehicle:



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