08-11-2019, 08:50 PM | #23 |
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This post will tell you all you need to know about the drivings modes and what they do/do not do.
https://f87.bimmerpost.com/forums/sh....php?t=1385679 |
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08-11-2019, 09:14 PM | #24 | |
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08-12-2019, 11:50 AM | #25 | |
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But indeed not mentioning data about engine cooling or overrun.
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08-12-2019, 12:10 PM | #26 | |
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But anyway, the "break them in hard" concept really comes from the crotch rocket crowd. It's been long debated that a hard break-in will "seat the piston rings quicker/better" than an easier break-in. My knowledge is more from car engines than from motorcycle engines, but I can see how people may believe that a 12,000 RPM motorcycle engine would benefit from a hard break-in......but anyone who has ever built an engine should know that there's very little truth to that, for obvious reasons. Anyway, opinions are like a-holes since everybody has one. That said, I'd be more inclined to follow the manufacturers break-in procedure, which usually calls for a more moderate break-in with varied levels of RPM during the first thousand or so miles. Either way, I don't think it will make a huge different to the engine over it's lifetime. Much more important is the way the car owner treats the engine over the years. For example, not going WOT with a cold engine....especially on a turbocharged engine. Also letting the engine idle for a minute before shutting the engine down, especially if you were running it hard shortly before you got to your destination. You know, those sort of things.... |
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08-12-2019, 03:00 PM | #27 | |
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But lets look at this theory logically. If we even assume a 2 sigma distribution of tolerances of clearance of piston ring seals, it would mean that 95.4% of said rings fall in a nominal rage of clearance. This covers most cars, so no problem. But what about cars at 3 sigma or even 4 sigma? They would have larger gaps in the rings. So the stock break in procedure covers most, but not nearly all. Those with higher variance need a different procedure then. More heat, more pressure more time at temp... and for reference auto industry strives to cover 6 sigma in a lot of cases. But not in all. My previous car burned 1/2 qt of oil in the first 3000 miles. Then I took it to a track day and it stopped. The following 39k miles till I sold it it din't use a drop. Why? It needed more heat and more pressure to seat the rings properly. But what about those in the middle, within 1 sigma? Will a harder break in or exposure to track day temps and pressure hurt them? Well a normal car does not get hurt by driving on track, or driving hard, does it? You don't loose your warranty for exceeding 6500rpm, do you? This is within the design parameters and the intended use case after all. So where is a downside here? Harder break in covers a higher distribution of cars. Some will still need an ever harder process to seal the rings. Very few will burn oil no matter what. Because statistics.
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