If You Modify The LTG Engine, Be Sure To Get A Tune!

The 2.0 Liter LTG Ecotec can be found in a number of cars that we work with: namely the 2013+ Cadillac ATS, 2014+ Cadillac CTS, and the 2016+ Camaro. There are also versions of this motor in the Chevy Malibu and other vehicles as well, so this advice would ring true for all of them.

We recently began working with a customer who came to us with a modified 2016 Camaro 2.0T. This customer was ready for their tune, so the mods were installed with the anticipation of having the tune done right away.

The stock pulls on this car show that with the bolt-ons this particular car is making a very healthy amount of torque. That is, until it hits the ECU's factory torque output limit and torque management steps in to greatly reduce the amount of power that the engine is allowed to put to the ground.

In the graph you can see that from about 3,750 RPM to about 5,750 RPM the power output of the car is significantly reduced. This will happen if your car produces more torque than the ECU's preset torque limit, and is a significant reason to make sure that you get a good tune to support your mods. For those of you wondering, the factory torque limit varies by RPM, so it's not one set value, but the max calculated amount allowed is in the low 300's. It is safe to say that amount is meant to most closely relate to the output at the crank, not at the wheels.

Without a tune this driver would be driving at wide open throttle with less than 200whp at some RPM ranges due to the torque management intervention, when they could easily be making well over 260 whp as is. The torque management on these cars is aggressive on the stock tune, and very unforgiving. that calculated value could even be thrown off by something as seemingly benign as a change in tire diameter too.

What is actually happening here is that the ECU is sensing the additional torque output and is commanding the throttle body to start closing (much like it does during traction control). As the driver you may feel this as a sort of "nerfing" or dead spot in the powerband.

In even more extreme cases the ECU will also start to report false knock retard in order to demand less airflow from the turbocharger. (there is a table that reduces allowed airflow from the turbo in the presence of knock, FYI).

Here is what the ECU commanded Throttle % was, despite the fact that the driver's foot was at 100% throttle the entire time: