ECU Remap vs Tuning Box

ECU Remap vs Tuning Box

ECU Remap vs Tuning Box

Do a quick search of the internet for advice and comparisons of a diesel / petrol ECU Remap vs Tuning Box and you’ll see an almost unanimous opinion that the remap, also known as chip tuning,  ECU tuning, mapping etc. is the preferred option to diesel tuning boxes.

Getting straight to the point: No diesel tuning box, however advanced or sophisticated it may be, can compete with a professional ECU remap for a better, and safer balance of performance, throttle response, economy and drive-ability.

To take advantage of any tuning your car / vehicle needs information, such as engine speed (rpm) and load, it is essential to know what the engine speed and load values actually are at any given moment.

If cost is the main reason that you are thinking of buying a tuning box rather than an ecu remap , speak to us, as we can often supply an insurance backed ECU remap with warranty cheaper than the cost of a tuning box.


Diesel Particulate Filter’s

Most modern vehicles are now fitted with a Diesel Particulate Filters, this helps to reduce emissions, which in theory is great, but in reality blockage of the DPF is a common problem. The DPF fitted in most cars needs to perform regeneration cycle, this is done automatically and should clear the Diesel Particulate Filter periodically, but it will only do so when the conditions are right for the regen procedure to safely commence.  Diesel tuning boxes are particularly likely to cause DPF blockage since they lack the ability to control fuel in accordance with engine speed and load. Such indiscriminate increases in fuel can cause frequent over-fueling, with the result being that particulates build up in the filter faster than DPF regeneration can remove them simply because your vehicles ECU is unaware that the Tuning Box is over-fueling your engine and particulates have increased.

BHP gains in diesel engines are easy to achieve, and choosing the ECU Tuner with the highest BHP figures can sometimes be likened to picking the one that’s bravest as it’s relativity easy to be brave with someone else’s vehicle / engine. Tuning boxes rely on intercepting signals from the Rail Pressure sensor, even though the ECU still controls the fuel rail pressure and it uses a sensor to confirm this as the figures are vital for the ECU to know the fuel quantity. If you add a resistor into this sensor circuit, as tuning boxes do, then the ECU is given false info, ie: 1500bar pressure is now reported to the ECU as being just 1400bar, so the ECU then thinks the pressure needs to be raised and activates the high pressure injection pump to raise the pressure by 100bar above the sensor value thus giving an actual pressure of 1600bar, when it should be 1500bar. The extra pressure then forces more diesel fuel through the injector and increases the work load of the Injector pump,  and the Injectors are now holding back greater forces. The Torque and Smoke limiters have been bypassed as the ECU doesn’t realise there’s increased fuel flow, resulting in unburnt fuel. This is why sometimes you’ll see a vehicle with a tuning box fitted being followed by a plume of dark smoke.



Economy and Tuning Boxes

The ECU in your car calculates your mpg based factors such as throttle position, engine load and vehicle road speed, with these figures the ECU will be able to calculate the amount of fuel used per unit of distance travelled.  Because a tuning box intercepts the fuel pressure sensor and increases the quantity of diesel injected at higher values than the ECU is expecting the economy will be overestimated as the ECU thinks it is using less diesel fuel than it actually is, giving you false economy figures. That’s not to say that there isn’t an increase in economy, often the economy does increase, but certainly not to the same level that’s being reported via the cars On Board Computer or Trip Computer.


Remapping vs. Tuning Boxes

Many people ask us this question, for a start a remap alters the actual programming inside the ECU, and doesn’t rely on intercepting or falsifying any sensor readings. A diesel remap will see the fuel injection quantity raised but only by telling the ECU to inject more fuel, the ecu will then calculate if the injectors require being held open for longer.  The fuel rail pressure may have slight increases which help with fuel vapourisation and economy. Turbo Boost pressure is often increased and this provides more air and oxygen which further allows greater injection quantities without becoming too rich and producing black smoke. The torque limiters are often raised to monitored levels under full control of the tuner who can also fine tune the Phase of Injection to keep exhaust gas temperature down.


Above all, the increases experienced in economy and power seen with a Remap are true and can be trusted, whereas Tuning Box’s only provide false data.

Are expensive tuning boxes any different?

Well, a tuning box is a device that’s external to the ECU that simply intercepts the rail pressure sensor and tricks the ECU into supplying more pressure to the fuel rail, there are devices fitted with a potentiometer   where you can alter the resistance added to the fuel rail sensor, but it is basically still just a resistor in a more expensive box, some even have extra circuits added, but it still comes down to tricking the ECU into supplying more pressure and fuel.

Even if a tuning box could supply real time adjustment of the falsified rail pressure signal it would require more inputs, such as engine speed, and the Torque Request, and any big changes would be immediately noticed by the ECU.  If the rail pressure sensor suddenly started to show a drop in pressure from a Tuning Box altering the signal, the ECU would assume that there is a failure in the pump, or a leak in the pressurised fuel rail, the result of which is likely to be an EML on your dash and limp home mode.

The purpose of the article is to help and give you the info required to make an informed decision on how you would like to tune your diesel vehicle.

Equally both Remaps and Tuning Boxes will bring your vehicle to life, although in different ways with different aspects of safety and different Pros and Cons. Contact us for your Remapping or Tuning box requirements.

Treat Your Vehicle to Optimised MPG, Enhanced Performance, Improved power Delivery and Lower Emissions