When it comes to performance tuning, every detail matters. This was proven when this 2013 automatic ZL1 hit the dyno for a head-to-head fuel comparison between E85 and VP Racing’s C85. The goal? To see which blend delivered more power and why. What unfolded was an eye-opening lesson on how a few tweaks — and the right fuel — can make a big difference.

The LT4 is a straightforward yet powerful build. It’s a testament to investing in the right areas without going overboard. With a 2.38-inch supercharger pulley paired with a stock crankshaft pulley, essential cooling modifications, and an idler to keep the belt from slipping, the setup is solid. The car also boasts an off-the-shelf Roto-Fab intake and a set of long-tube headers, and is tuned specifically to run on E85.

The initial pull on pump E85 set the bar high, with 600 horsepower and 625 lb-ft of torque at the wheels. For a moment, it seemed hard to beat. Once the team poured in C85 without changing the tune, however, the car roared back to life, posting significant gains on the graph, now showing 628 horsepower and 651 lb-ft of torque — an instant gain of 28 horsepower and 25 lb-ft of torque with no tweaks, no changes, just better fuel.

The day didn’t end there. Encouraged by the gains, the tune was cleaned up. The fuel mixture tweaked and a bit more timing was added. The results were electric: 644 horsepower and 668 lb-ft of torque. The car responded well to the C85, soaking up two to three additional degrees of timing beyond what the E85 tune had in place. The team knew they could push it even more but opted for a balance that kept reliability in mind. “Unless you’re running race gas all the time, you don’t need 23 degrees of timing in your boosted car,” the tuner explained. It’s a real-world reminder that moderation often wins the day.

To keep things practical, the car left with two tunes available — one optimized for race fuel, the other dialed back for regular street use on pump E85. It’s a smart strategy that gives him the flexibility to harness the car’s full potential while staying safe.

This dyno session reinforced an important takeaway: the right fuel can unlock serious power. While E85 showed its worth, C85 proved it could take things further with its exact 85-percent ethanol blend and high-octane petroleum distillates giving tuners and enthusiasts a much more consistent and reliable fuel when chasing those extra ponies.

The day ended with a nod to simplicity and efficiency. It wasn’t just about hitting numbers; it was about understanding what makes those numbers possible. Sometimes good fuel really is worth its weight in horsepower.