ECU Tuning – The Reality and The Myths

Diesel tuning

Basic engineering fact – Smoke is wasted energy. This is the product of a badly modified file, by normally adding fuel because its the easy and quick map to find with absolutely no recognition to thermodynamic principles, stoichiometry or Volumetric efficiency. A correctly modified file will provide the cylinder with the correct amount of air to completely com-bust the given fuel. Please understand that fuel is fixed sum (energy) for the ECU and air is variable, an engine is driven by the heating of air to gain the most power you must heat as much volume of air as possible from a relative due point (exothermic reaction), the fuel already in cylinder must be burnt completely to extract the most energy (allowing for the boundary layer), a complete burn of fixed fuel = more heat, more heat = more power, basic physics.

Smoke will damage a modern diesel engine

Manufactures go to huge lengths to achieve the perfect/maximum thermal efficiency in engine design striking the perfect balance from a induction temperature and the heating point of the fuel vs permissible exhaust temperature (EGT) whist targeting the idea push/pumping(expansion) cycle or adiabatic process. The problem in tuning a diesel engine for a manufacture is purely down to controlling EGT relative to particle matter and Nox (nitrogen oxide) emissions the very reason forcing the use of DPF systems.

So how is the damage done? – By modifying the lambda (fuel relative to air) the first issue is the over loading of the DPF management cycle as the filter is designed to handle a certain amount of matter vs measured flow vs a oil quality / engine ageing strategy, think of it like this – tuning a engine it is a given performance air filters provide more airflow by using better more expensive materials. Currently there is no material solution for DPF to achieve performance increase other than (at best) an increase regeneration cycles to keep flow optimized resulting in increased fuel use for such a regeneration leading to the inevitable shorted life cycle. So adding fuel = Dead DPF.

Turbochargers suffer greatly from tuning ignorance, and are a fundamental component in managing the efficiency of a engine. The compressor map of a turbo dictates the dynamics of the air heating process with the cylinder temperatures vs. EGT calibrated precisely known as the ‘flame wall’ as diesel fuel ignition timing is dictated by the mass vs relative fuel temperature respecting thermodynamic variables / eg – the fuel pressure (endothermic reaction), fuel mass (duration), start of injection (timing). I see issues with calibrations where the mass (duration) is modified the SOI (timing) is modified along with increased rail pressure resulting in the movement in flame wall causing a cascade rise in EGT thus damaging the turbocharger due to the pardox of increased boost pressure only compounding the issue. Another issue born out of over fueling and flame de-tuning is the sooting of the exhaust wheel of the turbo causing a imbalance of the turbine and jamming of a variable geometry where applicable thus greatly reducing the life of the turbocharger.

Drive line and chassis harmonics – manufactures again go to huge length to control engine running frequency and this ‘noise’ causes long term damage to components a simple example is the presence of a dual mass flywheel which is tasked in part to countering this issue in conjunction with tuned engine mounts and phased injection strategies. By not respecting these components in a file modifications all will lead to early failure.

The work is already done in the ECU to increase the performance to a sensible point without compromising the powertrain the key is understanding the physics on which the calibration was designed, so the next time you see a Youtube video of a vehicle pumping a dyno cell full of black smoke think about what you have read here and the ignorance of some tuners.

EGR Removal on DPF vehicles

It is bad idea. I am currently seeing alot of companies offering EGR deletes on vehicles equipped with LIVE DPF systems. I do not offer this service (unless you strongly demand) for a number reasons. First of all, as part of the integral emissions system that was embedded into the software, the EGR and DPF systems work together in the regeneration process.

If the EGR system is deleted by means of duty cycle and airflow modification, this will have a negative impact on the DPF regeneration cycle. The DPF system was designed to work along side the EGR using different strategies in the passive and active regeneration process.

Once the EGR is modified, by default, this will upset the regeneration strategies and more often than not, result in an early DPF filter failure due to incorrect regeneration strategies.

Custom Tuning Files

Fact – in ecu tuning there is no such thing. This is impossible to modify your file by your vehicle’s odometer count… So do not trust the companies who advertising that tuning file for your personal vehicle is custom made and adapted regarding you engine’s wear condition. You will get a standard tuning file upon your request (Stage 1, Stage 2 etc), but you will pay more.

Clone or copied Tools

FACT – with most things in life, there will always be copies, clones, rip offs. For example DVD movies and CD Albums. When it comes to chip tuning, Yes many tools have been copied/cloned etc. A quick google search will reveal the extent of how many clone tools are a wash over the internet. As an example, try and search FGtech for the legitimate FGtechnology website, lets put it this way, its not in the top 10 results. The fact that China has gone all out on manufacture and marketing of these tools, and even to the point of starting websites with very similar names means that people very little experience in chip tuning may be duped into thinking they are buying a legitimate tool a fraction of the cost of the genuine article.

Do they work?

Of course they do, but as clones are clones and it will be up to the user to test. The quality of the components and construction varies. The tools cannot be used while connected to the internet, so they cannot be updated to the very latest software/firmware, some protocols may or may not work due to old or corrupt software/hardware. The best source of information on these tools is the internet, like a chip tuning forums and other websites.

Genuine tools are built as the manufacturer intended, all of the protocols listed 99% of the time is working, so there is no real chance of error.

So in conclusion, clones are usually working as well as genuine tools, but there is a bigger chance of error.

All this information is based on the books which I read during my experience on ECU tuning.


  1. d333gs says:

    I am very new to tuning and know very little…….I hope to change this!

    I have a couple of questions in regards to engine heat:
    I installed a RaceChip Pro on to my 07 Mini CooperS. My impression on the first run was “WOW!”.
    BUT the engine got very hot very quickly. The second run was less “WOW!” and the engine did not get as hot. QUESTION: Did the ECU adapt , i.e. make corrective changes?
    Some kids ripped off the non functional hood scoop which now allows the now open hole to let a lot of air in……..I realize this could be my imagination, BUT the car seems to run better?

    (3) Can you suggest any books that would give me the basics of what the ECU does?

    Thank You

  2. leedibnah says:

    Audi TT 225 bhp remap absolutely superb, smooth power throughout the rev range and lots more of it!

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