ECU FAQs

Atty. Jerome G. Neri
The Scrutineer

I HAVE been receiving a lot of queries about Engine Control Unit (ECU) tuning and reprogramming. So here is a list of the most common questions I get and the corresponding answers.

Can any car ECU be tuned or reprogrammed?

Not all ECU’s have hardware and software available on the market so that it can be tuned/reprogrammed. The hardware needed is a cable or device that can download and upload the tune from the ECU. Software is needed to be able to edit the tunes in a computer.

What are the tuning alternatives if my car’s ECU cannot be tuned/reprogrammed?

For a car that has no hardware and/or software available, to tune its ECU, there are aftermarket programmable ECUs. There are two types of aftermarket ECUs: the stand alone and the piggyback. The stand alone ECU replaces the original ECU of the car. A piggy back ECU is added-on to the original ECU and works together with the original ECU. A stand alone ECU can do a lot more than a piggy back ECU. Knowing whether or not to get a standalone ECU or a piggy back ECU depends on the set-up of the engine and the horsepower goals for that engine.

Is there a significant increase in horsepower by getting an ECU tune?

It really depends on the engine. Generally, there are significant gains to be found on just a tune from forced induction engines. On naturally aspirated engines, there are no significant gains to be found from a tune when the engine is completely stock, such that supporting mods are recommended for naturally aspirated engines to complement the tune.

Will my fuel economy improve by getting my ECU tuned?

No. There are a whole lot of claims that a car can be tuned for more power and better economy. I do not believe in that. If you want more horsepower, fuel economy will suffer. An engine gets the most horsepower when the correct amount of fuel is mixed with the correct amount of air. Modern engines are programmed to use the least fuel possible that will not damage it, so that when I tune an engine for more horsepower, I find myself adding fuel, and, of course, when fuel is added, then the more the fuel consumption will be.

Dyno tuning is expensive – can we just do a street tune?

Actually, if you have a proper tuner, tuning on a dyno will come out cheaper than street tuning. Dyno rental rates in the Philippines is at P4,500/hour, and with a good tuner, the job can be done between 1-2 hours depending on how easy/difficult it is to tune and reprogram the ECU. The result of this 1-2 hour session on a dyno is a perfect tune as the data that is gathered in dyno tuning has very good resolution, since the pulls are done in fourth gear. What is saved on dyno time but tuning on the streets is replaced by additional professional fees to the tuner, as street tuning would easily take more than double the time as compared to tuning on the dyno. Moreover, it is very difficult and risky to do more than a dozen pulls in fourth gear as the car will be reaching speeds over 200kph on the streets, and therefore, data logging will have to be done in third gear, giving the tuner less resolution on the data, which is used as the basis in tuning the ECU.