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At RPM-Motorsports we have been working with the GM Ecotec Platform since 2004, and have seen a few different generations of ECUs come and go over the years. We started off with tuning the Ecotec way back when the little Chevy Cavalier gave you practically less options to adjust than a common household VCR. Over the years we evolved with the platforms, to the more advanced Chevy Cobalts and their introduction of the MAF sensor to the Ecotec family, followed by the Bosch torque-based ECU found in the Pontiac Solstice GXP, Saturn Sky Redline, Chevy Cobalt SS, and HHR SS.
That first torque-based ECU was a curveball to the typical dyno tuner back in its first year of introduction. Some more complicated concepts that were typically only seen in Diesel engine applications were now starting to make their way into the engine management of gasoline powered engines. Things like Torque-based Airload, and Direct Injection settings started to look like a foreign language to most. We quickly adapted, and got ourselves at the forefront of tuning the LNF engine, and quickly adopted the LTG engine when it was introduced too.
The LTG brings a lot more complication to the process of tuning an automobile, and even though it has been around for more than 3 years there are still a lot of people puzzled by it’s inner workings. This logic now applies to even the mighty LS series V8 engines, which has come as a shock to those shops that have not been keeping up with the times in the 4-cylinder and 6-cylinder direct injection world.
The real basics of the good ole days are gone, and tuning a car to run properly is rarely as easy as just turning up the timing advance until it knock and then dialing it back a little, and dialing in your air fuel ratios to where you are happy. Now there are calculations for axle torque and predictive coefficients that must be taken into consideration, as well as a spider web of tables that cross-reference each other to keep things in check.
Tuner are now facing tables like the Driver Demand tables that indicate the amount of torque that the engine should be allowing/demanding. This table does not exist as a perfect 1:1 relationship with reality.
We also see tables like Peak Engine Torque coming into play, though you can see that these values are not perfectly related to the Driver Demand table, yet these tables work together to target and limit calculated torque output from the engine. “Calculated” being the operative word, because if you spend some time looking at logs you will see that this number is also something somewhat arbitrary to the ECU itself. If you look at these tables in an Automatic Equipped car versus a Manual Transmission equipped car you will also notice that their values are wildly different, as the ECU uses a different method of torque calculation in each.
From there you will find a plethora of other tables that require careful adjustments in order to ask the engine to demand more power. The relatively complex ECU found with the LNF engine now seems rather elementary compared to that found with the LTG in the 2016 Camaro 2.0T. In fact, the logic in this ECU shares more in common with the newer ECUs found with Subaru’s FA20DIT engine that comes with the 2015+ WRX and 2014+ Forester XT.
Boost control now becomes a delicate balance of torque targets and wastegate duty cycle tables that simply airload limits and torque percentages. You cannot simply max things out to 100% and expect this LTG to want to pick up steam.