2015 Corvette Z06 Owners Report Heat Soak Power Loss, but it’s actually a conservative ECU, claims General Motors.
The 2015 Corvette Z06 has hit the streets, and more than a few owners have started complaining about experiencing a power loss after back to back runs on the highway, or multiple laps on the track. They rushed to point the heat soak finger at the LT4 motor in the Z06, but this doesn’t seem to be the issue here.
First, let’s explain what ‘heat soak’ is: After a few full-throttle runs, the engine bay gets hot and starts sucking in warm air into the supercharger, resulting in a loss of horsepower.
Furthermore, the hot intake air charge also increases the risk of detonation. The ECU measures the intake air temperature – both before and after the charge – and when the after charge temp. is too high, it starts pulling timing to protect the engine.
Going back to what we said, though – these ‘performance issues’ aren’t just an issue with the LT4 supercharged V8 in the 2015 Z06, or at least that’s what the tuning scene is saying.
The crew at Vengeance Racing started playing with the C7 Z06 last week, and they came across this same issue. According to them, this this is all a conservative ECU setup.
So far, they only did repeated runs on the dyno, where they recorded a notable 20-degree difference between the two aforementioned intake air temperatures. They also performed several highway runs, and they’ve had 5 to 7 minute breaks between runs to analyze the resulting data and make changes to the ECU.
Once again, as Vengeance Racing explains, there doesn’t appear to be any heat soak issue at all – and such a problem wouldn’t make sense anyway – not after all the testing the Z06 has been through, and after GM hit the jackpot with the ZR1 in the past.
In a thread on Corvette Forum, the tuner explains the issue lies with the ECU – “With the OE calibration we did experience the same thing… The timing tables are EXTREMELY conservative and the ECU will pull timing for almost any situation. I am waiting for owners to complain about “tip in” as the ECU pulls a massive amount of timing when slightly touching the gas pedal”
We know it sounds convenient for a tuner to say this, but Vengeance Racing also claims “most of the loss of power can be addressed in the ECU.”
Of course, this may just solve the problem reported by multiple owners, but it will also void the powertrain warranty, not exactly something you want on a $100,000 car, unless you were planning on modifying it in the first place.
Furthermore, after a video surfaced the other day of a bone-stock SRT Viper walking a brand new C7 Z06 during some freeway runs (video below), the performance car world has been buzzing – and even GM has finally stepped into to explain:
“The reasons behind the ECU setup reigning over the LT4 V8. To put it shortly, Chevy wants to make sure the Z06 meets emission targets and keeps placing those 650 ponies at the mercy of your right foot for at least 10 years or 100,000 miles (160,000 km), which are the intervals covered by the warranty.”
To use the automaker’s words: “We are confident that the vast majority of customers are going to be more than satisfied with the performance the Z06 offers in stock form. For those that want more power, they can visit an aftermarket tuner – who are not held to the same standards [emissions and warranty] as an OEM. However, this presents significant risk to the customer. An aftermarket tune voids the vehicle warranty as Chevrolet cannot possibly test or confirm the durability of their calibration; and aftermarket calibrations could cause drivability issues that are not present in the factory setting.”
When asked about a possible track tune, that would unlock some extra potential for limited amounts of time, GM said they are not planning such a move.
Basically, GM acts like a father who’s giving you a car – it hands you the keys and whether you want to enjoy the supercharged thrills in marathon or sprint mode, the choice is yours. It’s just that you must remember to cover your dad’s 100 grand pension fund in return, on the spot.
Thanks to Auto Evolution for the heads up.