Review of the TDI-Tuning box

"Superb, easy to fit and versatile tuning in a box"

Here is a long overdue review of an actual tuning box.

The chaps at TDI Tuning let us see their latest tuning box on a 3.0 v6 TDi Audi A6 Allroad backed up with Dyno results.

We must stress there are tuning boxes and there are tuning boxes. These tuning boxes from TDI Tuning contain a cpu and store programs and act like piggyback ECU's. They offer an extensive tuning boost. Don't confuse these with the simpler non microprocessor boxes you buy on popular auction sites.

I was impressed so I have since requested one for my own petrol A3 1.4 TFSi and am pleased with the results it gives. You can watch our video review here....

The tuning box plugs in between the (engine control unit) ECU and engine sensors.

There are tuning boxes in name only, and tuning boxes in deed, this thankfully is the latter!

The ECU controls the essential aspects of the engine, controlling fuel, ignition timing and turbo boost. It takes readings from sensors around the engine that tell it the engine speed, engine temperature, air intake temperature, boost pressure, fuel pressure, the amount of oxygen in the exhaust (which indicates a clean or dirty burn and more.)

The ECU does a good job at combining all of these data points and making useful decisions to keep your engine running smoothly and efficiently. However, car ECU's are designed to work across multiple markets with various grades of fuel and different operating conditions so they opt for a safe tune that will work ok and will meet even the most stringent emissions regulations.

This suggests that each engine has great untapped potential if the parameters could be set for high quality fuel and tweaked to provide the optimum power delivery.

A tuning box sits between the engine sensors and the ECU and takes the readings provided by the sensors and manipulates these before they go to the ECU.

It then alters the output commands that would come from the ECU and takes over controlling the various engine components to give more power.

The faster the tuning box can process the data the smoother and better the engine will perform, a modern piggyback ECU or tuning box can do this more quickly and efficiently than a cars standard ECU.

As the engine speed and fuel pressure alters, a smart tuning box reads the live data from the engine to provide instant changes and then feed data back to the ECU based on it’s calculations for the ECU to dish out the commands and settings needed by the driver.

On to the car, and we have our Audi A6 Allroad, a good solid car for tuning. This car is a bit of a challenge to a tuner as it combines traditional analogue sensors with modern digital sensors.

We chose TDI Tuning after a conversation with their tuning team about the complexities of the A6 engine and what they offer which perfectly matched our requirements.

We didn't want to chase a large peak power figure and were looking for more power and torque across the entire rev range.

We also wanted an economy option and sports option and with the 7 programs stored in the TDI Tuning ECU we had plenty to choose from.

We should stress that these are 7 separate programs, not just tweaks up and down from a standard program.

We were impressed by the professionalism of TDI Tuning who are a manufacturer and seller of state of the art tuning systems who do their own research and development - you can ask for specific maps, for example if you were towing or had other unusual requirements.

Review and testing

The instructions for fitting provided were very comprehensive and easy to follow. Within about 20 minutes we had the tuning box installed and ready to go.

We took it out on the economy setting (1) at first with TDI-Tuning’s permission. The car pulled noticeably better and felt much nicer to drive. We can't really comment on the fuel economy as we would prefer to take a week’s driving to compare and we haven't had the opportunity yet. The dash MPG indicated did seem to show about 15% improvement over what we were used to on similar parts of the road. TDI tuning state up to 20% more fuel economy.

The next job was to try out the maximum performance setting, where everything is turned up to a safe maximum.

The car felt totally different, and literally pulled like a train. The boost seemed to come in a lot sooner and more smoothly and it felt like we were driving on a wave of Torque.

We may sound a little crazy here but even at the max the fuel economy still seemed to be slightly better than what we are used to, probably because you needed less throttle to make the same progress. Obviously if you drive it hard your economy will drop but your smiles per gallon will increase!

We haven't tried out all of the options yet, there are 7 to choose from and we really like the performance one. For our daily commute we'll opt for program 4 which gives a really good mix of power and economy. For holiday drives and long journeys we'll switch it to program 1 and get the benefit of the economy.

If you look at the rolling road printout to the right (click it to see the full PDF) you'll see the improvement to the torque curve across the entire rev range which really has to be driven to be appreciated.

We could probably have got a higher peak figure with a custom tune/remap but we certainly wouldn't want to sacrifice a wide power band to hit a pub bragging rights figure and put strain on the turbo and engine to get there.


We are very happy with the results we saw from the TDI-Tuning box and can definitely recommend it - it does everything the makers claim acting like a proper piggyback ECU.

It was easy to install and worked as well as our prior experiences with tunes or remaps on other engines.

I have since fitted one to my own 1.4 TFSi Audi A3 and am very pleased with the results, although diesels seem to give more power when tuned, it still lifts performance noticeably for me and makes the car more fun to drive.

It can be viewed as a tune/remap by post, so you don't have any of the inconvenience of taking the car in for a remap.

The benefit of being able to unplug the box and return the car to standard in a completely untraceable way means we’ve got no qualms about fitting it to an otherwise stock vehicle.

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5 Responses to “Tdi Tuning box review”

  1. Kevin says:

    You really need to measure MPG improvements manually – as the tuning box effectively manipulates rail pressure readings to the ECU, tricking the ECU into increasing fuel pressure to deliver more fuel (to generate more power) the cars OBC will be out as this increase in fuelling is not ‘seen’ by the car.

  2. Eddie Roux says:

    Hi Kevin

    I fully agree. My trip computer shows that the car is much “lighter” on fuel, HOWEVER, as you stated, this is not true. Trip computer is way out. MUST calculate it manually by using ACTUAL km, and ACTUAL distance.
    To this, the companies seem to be advertising false numbers when it gets to fuel savings????
    Please let me know your thoughts.


  3. Arthur Clement says:

    Obviously if you drive it hard your economy will drop but your miles per gallon will increase– , Decrease surely.

  4. TorqueCars says:

    Well spotted, that should actually read SMILES per gallon so it was a typo, but not what you were expecting.

  5. TorqueCars says:

    This review has attracted lots of rather suspicious comments presumably from a rival tuning box maker. We stand by this review of TDI tuning boxes. This unit is fitted and used daily on my Audi A3 1.4 TFSi, and I’ve seen other TDI tuning units tested on the DYNO and outperforming other tuning boxes.

    Please note: Comments, Threats, and “reviews” posted from proxy IP addresses, or with random/fake names will not be published! – You know who you are…

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