When Chevrolet introduced the 2020 C8 Corvette, it marked a revolutionary moment in American automotive history. For the first time in Corvette production, the engine sat behind the driver, transforming the iconic sports car’s dynamics. The mid-engine design, paired with the LT2 V8, delivered blistering performance with a 2.8-second sprint to 60 mph in Z51 trim. But in the world of performance engineering, enough is never enough. While the C8’s “Global B” electronic architecture initially posed challenges for tuners, innovative minds in the aftermarket community have finally begun cracking the code. At the forefront of this breakthrough is Howard Tanner, President at HTR Performance Engineering and lead calibrator for Vengeance Racing. Buckle up as Tanner brings us along for his LT2 intake testing.

LT2 Intakes: Stock vs. Carbon Fiber

In a recent testing session, Tanner and his team conducted an interesting comparison between the stock and PTR intake manifolds for a 2024 C8 Z51 Stingray. The subject vehicle, equipped with upgraded Vengeance Racing CNC-ported heads, camshaft, and headers, served as the test bed for comparing the stock LT2 intake that comes on the Stingrays against the Performance Design PTR carbon fiber intake manifold.

The PTR intake offers plenty of plenum volume. Luckily for C8 owners, hood clearance isn’t a big issue for tall intake manifolds.

Understanding Modern ECU Complexity

The complexity of modern engine management systems poses unique challenges for tuners. “Much of today’s controllers are what are known as coefficient-based airflow models,” Tanner explained. “Complicated algorithms are used to make instant changes to the engine’s airflow model, which is then used for various other functions. Only the OEM has the tools/software to properly make these changes.”

Fortunately, advances in aftermarket tuning technology have provided solutions. “HP Tuners has developed a tool portal to be able to extrapolate these coefficients to more user-friendly data that can be modified and converted back to the coefficient data,” Tanner noted. “Neural networks require ‘training’ so they can better conform to the changes in airflow that occur with modifications such as head/cam and forced induction applications.”

Dyno-Proven Testing

Testing was conducted on a Mainline hub dyno, chosen specifically for its consistency. “I use this dyno a lot for accurate testing as it’s dead consistent. Also, taking the wheels/tires out of the equation further helps consistency,” Tanner told us. The team maintained strict control over testing conditions, ensuring consistent weather conditions and engine/oil temperatures throughout the evaluation.

Power Behavior

The results proved fascinating. While an aftermarket intake is suspected to achieve horsepower and torque gains, the power delivery characteristics showed notable differences. The PTR manifold produced 509.9 horsepower at 6,591 rpm and 436.0 pound-feet of torque at 5,239 rpm compared to the factory LT2 intake manifold 468.8 horsepower at 6,543 rpm and 409.5 pound-feet of torque at 5,423 rpm. Gains of 41.1 horsepower and 26.5 pound-feet of torque are impressive for a manifold swap, but the impressive differences are shown from just 3,000 rpm to redline.

The PTR manifold demonstrated superior horsepower and torque characteristics, not only adding power at the top of the rev range, but also adding big gobs of torque in the mid-range compared to the stock unit. Tanner provided insight into these differences, explaining the complex physics at play: “If we picked up torque, we picked up airflow. It’s just physics. People often don’t understand that an intake manifold also works off sound waves that resonate from the intake valve back to the inlet. Pulse in an intake plays a big role in this. It’s very similar to those who understand how a two-stroke motor works with no valves. Sound is chasing the airflow. The PTR has a bit longer runner and a larger plenum so that can lead into much more ‘tuned’ frequency at those points.”

Intake Design

The LT2 intake testing highlighted the intricate relationship between intake design elements — runner length, plenum volume, and even the runner angles — and their effects on what Tanner terms “charge motion.” These design variables create complex airflow patterns that directly impact engine performance across the RPM range.

This is how you use an engine as a flow bench. – Howard Tanner, HTR Performance

“Interestingly enough, after reviewing the data logs between both intake tests, I could see factory widebands chasing the increase in airflow, which further substantiates that there was an increase in airflow at those spots,” Tanner explained.

Continuing The Legacy

This LT2 intake testing session is another chapter in the ongoing evolution of Corvette performance. Through the combined efforts of companies like HP Tuners and experts like Howard Tanner and Vengeance Racing, the aftermarket continues to unlock new potential from Chevrolet’s latest masterpiece. This effort maintains the small-block Chevy’s legacy of power and performance well into the 21st century.