C7 ZR1 Exhaust Flames

[John]

Under certain conditions, the 2019 ZR1 can, by prolong shooting engine flames out the exhaust, potential damag the ZR1 badge and the rear fascia. Thanks to CorvetteActionCenter for the following Service Bulletin. Thankfully a software reprogram can fully solve this issue.





https://www.corvetteactioncenter.com...ile.php?id=146

[Ateupjoe]

The flames are a misfire? And I thought it was all done on purpose. Silly me.

[John]

Actually both. The excessive length of time of the flames is a misfire. The actual flames are cool, and as you know, a secondary by-product of both intake port and cyclinder injection — as result of unburnt fuel being superheated.

[Ateupjoe]

John, I respectfully disagree and here is why. Please correct me where I a wrong in my analysis and conclusion.

There is nothing in this writeup mentioning purposefully displaying flames unless you're referring to the second line where it states that "a fuel injector may be commanded on.....". This begs the question of how this feature is commanded on? Is there a flames on button with this feature? If no, then the rest of this same sentence references this being a misfire and not something done on purpose.

[John]

I can only share that at the ZR1’s reveal, that Tadge was happy to share (bragging is excessive to describe it) that due to the dual injection fuel mode, that under certain circumstances that flames were coming out the back. GM even released a video of this.

There is no switch to turn on or off to create the flames. Additionally, TSB notes that this is only happening on certain vehicles.

Fuel delivery is handled by a combination of direct and port injection, a pairing that is said to be responsible for the car’s already-legendary ability to blow a jet of blue flame out of the exhaust at wide-open throttle.

My take, could be wrong, is that there is no inherent problem with short term flame duration, but when there is a 7.5 second long flame as a result of a misfire, that is when there is a potential for flame damage, and since they are not going to change the dual fuel injection, that some vehicles are having an issue with too long a flaming occurrence.

The correction is a ECM software reprogramming, something to prevent long duration flames. Reprogramming it will reduce the flame time duration lengt of the misfiring, and thus reduce fascia damage as a result of flame overheating it.

[Ateupjoe]

Ok thanks.
now excluding this misfire and no actual flame on/off button, can one turn on the flames at will via acceleration or shifting or something else?

[John]

Sorry, the only last thing I was just able to learn was that this happens at full throttle.

[Milliwatt Rob]

Well, I guess I better forget about driving a ZR-1 through an old leaky oil refinery. I could blow the place up.