Crud_muffin
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- e-Golf
Jason from from Engineering Explained has helped bring to light a condition in our turbocharged engines, tuned or not. You'll want to see his video and supplemental links below.
Basically, in modern engines like ours - small displacement, turbocharged, direct injection - there's a phenomena when the engine cycles for a duration in a lower RPM, high load situation (i.e., initial WOT on the highway) that produces engine knock/ping. (Note: Yes, this is the kind that breaks spark plugs and pistons, but is not turbo flutter from proper diverter/wastegate operation that you can volume down with soundaktor settings). Here's the kicker - normal downshift isn't enough, and it's not overcome with higher octane or tuning spark/timing advance. The reason being is there is an agent present in the cylinders that, under the right pressure conditions, becomes like a piece of BBQ charcoal, for lack of better words, that ignites what's left from ordinary fuel trim cycles in the cylinder before the proper time. Again, it's a unique condition; please don't feel guilty if it's happened to you when you felt you were driving normally.
Here's a video clip illustrating the ignition issue courtesy of Afton Chemical:
https://youtu.be/7L5XLPN_G3Q
Although using DSG 'D' automatic mode to downshift isn't always sufficient to raise the RPM's high enough to cycle outside the dangerous range, using DSG 'Sport' mode generally will. And for you MT folks, the engine's fate is in the palm of your hands (and clutch foot). When this topic has been brought up in MK7 threads, people have used 3k RPM as a safe mark. Simply being mindful of spending time in high gears with high load is all it takes. Also, the new oil specification, ILSAC GF-6, has tested vehicle makes across the board with this pre ignition phenomena in mind. The new oil is in the final stages of approval and anticipated to be on shelves April, 2018 - maybe the same time your oil change will be due anyway
Here's Jason's video:
https://youtu.be/soJea7xEt-8
Here's a Chevron site dedicated to the issue:
https://www.oronite.com/products/lspi.asp
Here's the official oil standard site:
http://www.gf-6.com
Basically, in modern engines like ours - small displacement, turbocharged, direct injection - there's a phenomena when the engine cycles for a duration in a lower RPM, high load situation (i.e., initial WOT on the highway) that produces engine knock/ping. (Note: Yes, this is the kind that breaks spark plugs and pistons, but is not turbo flutter from proper diverter/wastegate operation that you can volume down with soundaktor settings). Here's the kicker - normal downshift isn't enough, and it's not overcome with higher octane or tuning spark/timing advance. The reason being is there is an agent present in the cylinders that, under the right pressure conditions, becomes like a piece of BBQ charcoal, for lack of better words, that ignites what's left from ordinary fuel trim cycles in the cylinder before the proper time. Again, it's a unique condition; please don't feel guilty if it's happened to you when you felt you were driving normally.
Here's a video clip illustrating the ignition issue courtesy of Afton Chemical:
https://youtu.be/7L5XLPN_G3Q
Although using DSG 'D' automatic mode to downshift isn't always sufficient to raise the RPM's high enough to cycle outside the dangerous range, using DSG 'Sport' mode generally will. And for you MT folks, the engine's fate is in the palm of your hands (and clutch foot). When this topic has been brought up in MK7 threads, people have used 3k RPM as a safe mark. Simply being mindful of spending time in high gears with high load is all it takes. Also, the new oil specification, ILSAC GF-6, has tested vehicle makes across the board with this pre ignition phenomena in mind. The new oil is in the final stages of approval and anticipated to be on shelves April, 2018 - maybe the same time your oil change will be due anyway
Here's Jason's video:
https://youtu.be/soJea7xEt-8
Here's a Chevron site dedicated to the issue:
https://www.oronite.com/products/lspi.asp
Here's the official oil standard site:
http://www.gf-6.com
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