Hello all. Today, I decided to do an experiment to see just how effective ECU tuning is in-game, as well as how it translates to the real world.
Now, this isn’t a study of how much horsepower you can gain on turbocharged engines by simply ‘reflashing’ the ECU. Instead, this is a study of how large a difference you can make with a car’s cruising fuel economy by simply changing parameters in-game that would equate to nothing more than reprogramming the ECU on-the-fly while not driving in a spirited manner.
My experimental subject today will be this 5-door RWD hatchback, targeting the Family Sport demographic.
(Yes, the fixtures on this model are acting up a bit, that’s why this is open beta)
Every aspect of the car will be +3 quality.
The engine that I will be testing with is this 3.0L I6. It is N/A, DOHC 24V with VVT/VVL, and AlSi block/heads. It runs on premium fuel.
The first setup will be the engine in its ‘SPORT Tune’ configuration, with AFR set to 12.5 and ignition timing set to 100. It makes 273.9 hp @ 7200 RPM, and 241.9 lb-ft @ 4600 RPM.
When placed into the car, this is the fuel economy that the car returns:
27.4 MPG average, 33.9 MPG @ 75 MPH, and 50.7 MPG @ 43 MPH. That’s about average fuel economy for a car of this size with that much power.
Now let’s make a quick tweak to that engine. All I did was drop the AFR all the way down to 15.0, and tuned the ignition timing down to where the engine won’t knock. These are all things that an ECU is capable of doing on-the-fly without manual recalibration completely necessary.
As you can see, power and torque took a big drop by reducing the amount of fuel injected, as well as cutting back ignition timing. 245.3 hp and 216.4 lb-ft torque at the same RPMs; 10.5% reduction in power and torque. However, average fuel economy jumped by a significant margin, from 22.9% to 31.8%; a massive 38.9% increase in efficiency. Peak power and torque are meaningless when you’re just cruising down the highway, so the massive efficiency bonus is incredible, simply by adjusting AFR and ignition timing.
Now let’s look at the car’s fuel economy with this new state of tune:
Absolutely massive increases in fuel economy can be seen here. 38.8 MPG average, 47.3 MPG @ 75 MPH, and 73.6 MPG @ 43 MPH! Those are increases of 41.6% for the average, 39.5% @ 75 MPH, and 45.2% @ 43 MPH. Sure, straight-line performance is reduced, but if you’re just commuting in ECO mode to get the best gas mileage, the increase in efficiency is certainly worth it.
To summarize, by altering only AFR and ignition timing, which an ECU can do on its own almost instantaneously, you can have maximum performance when you want to drive spiritedly, or unbelievable fuel economy when just commuting or grabbing groceries.
So the real question is, why don’t cars in real life and in-game take advantage of such tuning to have both fuel efficiency and performance? Why must we make this compromise if the computers in our cars are able to make this drastic of an efficiency change while only sacrificing a small amount of maximum performance?
Thank you for reading, and I hope you enjoyed this quick experiment as much as I did.