Enthusiasts have realized the benefit of boosting the LS/LT-based engines found in many Chevrolet automobiles almost since they first came out in the 1997 Corvette. They respond quite favorably to supercharging and as a result, performance levels have risen sharply.
Chevrolet started getting into the action of supercharging their new small-block with the LS9 in the C6 ZR1 Corvette and the ZL1 Camaro. Peaking out at over 600 horsepower from the factory was a line crossed in the sand to all other car manufacturers who wished to market their performance cars. Since then, horsepower has risen considerably, and with the new LT4 engine in the 2015-2018 ZO6 Corvette and 2017-2018 ZL1 Camaro, 650 horsepower is the norm. When you consider that the last time this level of power was delivered from Chevrolet was back in the days of belching, cold-blooded, fuel-hungry big-block L88s, it becomes easy to see the benefits of today’s technology.
That is, unless you’re trying to go beyond the factory-ordained performance levels set forth by the engineers and computer geeks at GM. Sophistication is a two-edged sword. The very thing that controls the amount of fuel and air to such a level that it can seemingly utilize every molecule to its fullest potential, also controls how others may be able to manipulate it in the future. We went to the folks at SCT and asked them a few questions about the benefits and challenges of tuning such a highly sophisticated engine such as the supercharged LT4.
There are several obvious hurdles that rise up along the way for those who choose to reinvent the wheel when it comes to fuel tables and flow to our engines. On the one side, if massive amounts of horsepower were available by simply throwing a switch, wouldn’t it behoove any manufacturer to make it available in this “rise to the top” horsepower race that we seem to be having? The restriction more often than not, comes down to reliability, driveability and warranty claims.
When we’re toddlers, we play with plastic hammers, but as we age, the tools become more specialized, and our potential to punch holes in walls becomes greater. Preferably, as we grow, we learn to wield those tools properly. Sure, you can tell the difference between spark knock and some loose change in the cup holder, but not everyone is so adept. For those that are, there are some benefits to be had and, if you go beyond the stock configuration, there are even more smiles per gallon. But GM can’t decide who purchases their cars, so they engineer it with a performance envelope that is a safe distance from the edge of any cliff.
We heard that SCT had just obtained some LT4-equipped cars for testing and tuning and we asked the folks at SCT about some of the benefits and issues that they’ve found in tuning the LT4 engine for more performance. Keep in mind, that this focuses on the LT4, and not the LT5 engine as found in the new 2019 Corvette ZR1. That engine uses a totally different and highly complicated “dual fuel” architecture to control the port and direct-injection system for operation. Many companies are diligently working on ways to garner long-term performance gains from the new computer.
The folks at SCT are currently finalizing their work on the LT4 using the SCT BDX tuner. As such, a tune for the LT4 engines has not yet been released. But, the BDX can always be updated via Cloud Tuning over WiFi. Meaning, if you find an SCT BDX for a great deal somewhere now, you can get it and update the tuner when the new application is released. Here are a few questions to help you get an idea of what benefits you’ll gain once the tune is released.
Q&A From The Pros
We asked the folks at SCT about what benefits their BDX tuner will bring to the enthusiast and how it interfaces with both the Corvette and the Camaro with the LT4 engine.
What kind of gains (and where) can an enthusiast expect to see using this tuner?
For the LT4 supercharged platform, typical gains with our preloaded calibration are 15-25 horsepower and 25-35 ft lbs of torque with the most noticeable gains being the amount of torque increase down low.
What are some other goals of using the tuner, besides horsepower?
Our tuning devices have data logging functionality that allows you to monitor a number of engine and transmission parameters. It reads and clears ECM Diagnostic Trouble Codes and has dual, analog input capability to monitor air fuel ratio, temperature, and pressure sensors.
Is the SCT BDX simply a flashing device or is it adaptable to changes?
Yes! The tuning device can store up to 20 custom tune files (created by any SCT Custom Tuning Dealer) for reflashing the ECU. It has user-adjustable vehicle options to allow for cold-air intakes and rear gear ratio and tire size changes. It also stores the original factory calibration, to allow for easy restoration back to the factory calibration.
Is there expandability for future modifications?
Once future modifications are made, the user can have their custom tuning dealer build custom calibrations for the specific parts installed. With the ability to store multiple calibrations on the device, the user can have calibrations for different octanes or different types of fuel. They can even utilize a separate calibration for use of nitrous oxide for example.
What hurdles did the team have to overcome in cracking the code on the newer engine?
Today’s automobiles use an extensive amount of technology to bring the performance to the levels that we are enjoying today. As such, there is a lot that goes into the reverse engineering of the factory Electronic Control Modules. We have an entire team that works on this full time.
Can the tuner get into most of the areas controlled by the OEM computer?
Yes, the calibrator can get into thousands of parameters that live in the OEM computer. Torque Management, variable camshaft phasing, fueling and ignition timing maps are just some of the areas available for calibration, to name a few.
Can you adjust for different parameters so the MIL light still works, but perhaps might be better adjusted to any modifications?
Yes, for example if a larger cold-air intake or throttle body is installed, tables such as Maximum Airflow vs. Engine Speed can be adjusted to keep the vehicle out of a reduced power situation or a situation that may set a MIL light that is not warranted.
The Bottom Line
We couldn’t have today’s performance levels and still breathe clean air if it wasn’t for the amount of technology that today’s cars contain. Thankfully, companies like SCT are working hard to ensure that whether modified or not, that technology can be suited specifically to the style of driving that we do the most. Check out the website and see which SCT products are designed for your car and budget.