Why the Corvette C8 will be harder to tune thanks to over-the-air updates

Over-the-air upgrades (OTA) have become a popular talking point ever since Tesla debuted the feature on the Model S, so it’s no surprise that Chevrolet has added the capability to the new C8 Corvette. While OTA upgrades should save some trips to the dealer for small software reflashes, they also bring more complexity for those tinkerers that want to modify the factory computers.

Allowing OTA access to any vehicle requires better security and encryption, and the Corvette system will be no different. The basis of the electrical system in the C8 is the brand new General Motors “Global B” architecture. It comes with a variety of computers, such as the E99 engine control module that plugs into it. This increased level of security yields ECUs that have stronger encryption with fluid coding that is VIN-specific and harder to crack. Many of the modules require a piece of code from the GM side in order to be modified.

This development makes it harder for tuners to change the code in the ECU. They don’t have the other piece of the puzzle—the calculation that is done on the GM side to verify that the code in the ECU calculates out to a valid checksum. Some have made claims that this will render the new Corvette “un-tunable” by the aftermarket, but as Car and Driver correctly pointed out a couple of months ago, the electrical architecture and ECUs are not necessarily completely tied together and although they are symbiotic, they can still be modified separately.

Luckily, GM decided to test this new E99 ECU before the C8, when it was installed in the C7 ZR1. In hindsight this seems like a smart play, as it allows GM to get data back on the ECU from a lower-volume model before it spreads it to the whole line. A nice side effect, too, is that the aftermarket got a head start to crack the code.

While the E99 ECU cannot be directly programmed like previous GM ECUs, there are ways to get into it, as already proven by LS tuner powerhouse HPTuners. This Illinois-based outfit started working on the E99 ECU as soon as the ZR1 was released, and after some attempts at cracking the code, they found a way to reflash the ECU to accept changes from their software. These reflashes cannot be completed on a stock ECU, given the risk the system could possibly be bricked, so customers will require a specially modified ECU ordered from HPTuners if they want to get crafty.

The specially modified ECU adds around $2000 to the tuning cost if you’re sending your original unit to them as a core, or $2500 if you want to keep your ECU. The notes on the modified ECU state that it can only be modified with HPTuners software and tools so it’s probably a wise decision to keep the original ECU in case you want to return the vehicle to stock condition or enable updates from GM. In addition to the ECU cost, the software license requires additional credits from HPTuners, which is likely a reflection of the research and development cost that was put in on their side in order to unlock it.

Once the modified ECU is received from HPTuners, it still requires a few extra steps (and possibly a visit to the dealer), as the engine immobilizer is tied to the ECU and installation requires an immobilizer relearn by the GM dealer tool. Luckily, the relearn functionality is also available through the Service Programming System (SPS) which is available to independent shops and individual for those that don’t want to flatbed their Corvette over to a Chevy dealer.

Those that wish to use the new LT2 engine as a swap in another application shouldn’t be worried about these costs; it is very likely that GM will release an ECU kit once the engine is available in crate form. An ECU kit is already available for the LT5 engine from the ZR1, which contains the aforementioned E99 ECU, so it is likely that the LT2 engine may actually become cross-compatible with that crate engine ECU kit at some point. The standalone ECU kit may be a consideration by some Corvette owners but it cannot be used in OEM applications as it is not meant to interface with the other modules in the car and is only intended for use in swaps for other vehicles.

GM seems to have squeezed even more power out of the small-block but tuners are surely working on other ideas. The fact that the foundation for tuning options is already available bodes well for those considering a C8 Corvette purchase that they plan to modify.