What are the flex fuel conversion options for a Chevrolet Corvette C7 ZR1?

Converting a C7 ZR1 to run on flex fuel is a highly effective way to pick up power and keep the engine cooler, but because of the massive fuel demands of the LT5 engine, there are some hard limits you need to be aware of before you start.

Here is how the conversion works for this platform, your hardware options, and what to expect.

Hardware Options

The physical installation of a flex fuel sensor is straightforward.

• The Sensor Kit: The community consensus strongly favors the DSX Tuning plug-and-play flex fuel kit ⁴. While there are other options like Advanced Fuel Dynamics, C7 owners generally recommend sticking with the basic DSX kit for reliability ⁸.
• Monitoring Ethanol Content: You will need a way to know your exact ethanol mixture when you fill up. You can use a generic OBD2 scan tool with a custom PID, or install a physical P3 gauge ¹. However, a very popular and clean setup is running the Fuel-It Bluetooth module inline with your DSX sensor; this sends your ethanol content directly to a phone app without tying up your OBD2 port ⁸.

Tuning Requirements

Installing the hardware does nothing on its own. The factory C7 ECM actually has flex-fuel capability built into it, but the tables are disabled from the factory ⁶.

Once the sensor is plumbed in and wired to the ECM, you must have a tuner flash the ECM to turn on the flex-fuel tables and adjust the tune for ethanol ⁴. It is critical that you use a tuner who is highly experienced with the GM LT Direct Injection platform, as an improper E85 tune on these engines can cause severe drivability issues or engine damage ⁹.

The Catch: Fuel System Capacity

The factory lines and seals in the C7 are fully E85 compatible, so the fuel itself won't degrade your system ⁶.

However, E85 requires about 30% more fuel volume than premium pump gas to hit the same target AFR. Because the ZR1 makes so much power, you cannot run straight E85 on the stock fuel pumps and injectors. The 2019 Z06 shares the same upgraded low-side fuel pumps as your ZR1, and tuners generally cap max-effort driving at an E50 to E60 blend on that factory pump setup ⁷.

If you want to run full E85 (E85 straight from the pump without mixing in 91/93 octane), you will be forced to upgrade the fuel system. Standard practice for maxing out E85 on supercharged LT engines involves adding an auxiliary low-side fuel pump, a larger high-pressure fuel pump (HPFP), and larger injectors.

Difficulty: Moderate. Plumbing the sensor and tapping the ECM is an easy-to-moderate driveway job, but the mandatory custom tuning requires a professional.