07-26-2021, 10:46 AM | #2 | |
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This was Roundel Technical Editor Mike Miller's opinion on the subject in the March, 2019 issue:
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09-14-2021, 09:25 AM | #4 |
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I have a temp gun at home, I should take some temps with and without the cover to see if it does trap heat in.
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aerodavew10.50 |
09-14-2021, 09:44 AM | #5 |
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The B58 engine is deliberately designed to keep as much heat in for as long as possible after shut off to speed warmup after re-start. The "engine encapsulation" system which incorporates the cover and splash shield insulation is designed to retain heat up to 36 hours after shut off.
If the engine temp is within normal operating range when shut off (can be checked using the hidden menu), it doesn't make sense to try to make it cool down faster in any normal use scenario, other than avoiding heat soak of the intake between runs at the track, then you want to just open the hood and not take the engine cover off. The cooling system during operation should keep the engine at optimum temperature, both too hot and too cold are problems. |
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09-14-2021, 04:38 PM | #6 | |
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At the same time, I don't doubt that BMW, along with other manufacturers, are taking advantage of improvements in materials science as they relate to the plastics available for use in high-heat environments. BMW would certainly cut it close, though, if that saved even a small amount; perhaps that has something to do with the M235i/N55 charge pipe failures.
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2017 M240i: 25.9K, 28.9 mpg, MT, Sunroof Delete, 3,432#, EB, Leather, Driving Assistance Package, Heated Front Seats | Sold: E12 530i, E24 M635CSi, E39 520i, E30 325is, E36 M3 (2)
TC Kline Coilovers; H&R Front Bar; Wavetrac; Al Subframe Bushings; 18X9/9½ ARC-8s; 255/35-18 PS4S (4); Dinan Elite V2 & CAI; MPerf Orange BBK; Schroth Quick Fit Pro; Full PPF |
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aerodavew10.50 |
09-15-2021, 02:13 PM | #7 |
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Best thing you can do is not drive your car.
I'm not sure on the exact science behind it, especially with these plastics. But, heat cycles will happen every time you start your car. I don't see how cooling your car faster would help anything, the damage is done. https://en.wikipedia.org/wiki/Thermal_stress "In mechanics and thermodynamics, thermal stress is mechanical stress created by any change in temperature of a material. These stresses can lead to fracturing or plastic deformation depending on the other variables of heating, which include material types and constraints.[1] Temperature gradients, thermal expansion or contraction and thermal shocks are things that can lead to thermal stress. This type of stress is highly dependent on the thermal expansion coefficient which varies from material to material. In general, the greater the temperature change, the higher the level of stress that can occur. Thermal shock can result from a rapid change in temperature, resulting in cracking or shattering. " I also noticed drier climates degrade some plastics a little sooner, salt spray likely doesn't do any favours either. |
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09-20-2021, 07:58 PM | #8 |
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Another reason to leave the cover on is to mask the sound of the injectors. Those direct injection injectors make a serious racket. So much quieter with the cover on.
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09-24-2021, 11:19 AM | #9 |
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I leave mine off so that:
- It's easier on the valve cover, wiring harnesses, and other plastic components that sit under the cover. The engine covers are not just plastic but also have very thick insulation. - Allows for easier inspection of leaks or weeping The S55 has a tiny useless engine cover and the M cars don't run underhood heat shielding either. I did the same with my M235. |
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aerodavew10.50 |
09-26-2021, 11:00 PM | #11 |
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Off in summer, On in winter
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