[aerodavew]

Is the engine cover necessary or does it just hold in unnecessary heat?
Cons to removal?

[gosi]

Sound insulation. Also the engine has a dedicated cooling system that doesn’t involve cooling through the engine compartment and bonnet. So no gain or loss from it.

[overcoil]

I think the engine cover may also be a pedestrian impact device - so head hits plastic instead of hard metal. I’m not certain about the engine cover but do know that many car designs in the front are dictated by pedestrian impact and particularly head impact.

My cover also keeps little rodents from eating wires to some extent - I see the nesting material

[mikeysosa]

Originally Posted by ScottSinger

I think the engine cover may also be a pedestrian impact device - so head hits plastic instead of hard metal. I’m not certain about the engine cover but do know that many car designs in the front are dictated by pedestrian impact and particularly head impact.

My cover also keeps little rodents from eating wires to some extent - I see the nesting material

I can't tell if this is a joke or not...

[overcoil]

Originally Posted by mikeysosa

I can't tell if this is a joke or not...

No joke - I thought I read auto designers lament the frontal impact requirement and pedestrian impact test since hoods have to be higher to make crumple space above the top of the engine.

[OldCrow7xx]

Originally Posted by ScottSinger

I think the engine cover may also be a pedestrian impact device - so head hits plastic instead of hard metal. I’m not certain about the engine cover but do know that many car designs in the front are dictated by pedestrian impact and particularly head impact.

My cover also keeps little rodents from eating wires to some extent - I see the nesting material

Our valve covers are plastic too. I know because mine cracked off last year and leaked oil on the turbo manifold! What a mess. So its basically plastic on plastic I think.

[gosi]

The pedestrian protection thing is (at least in Europe) a set of struts with explosives that lift the bonnet at the back where the hinges are, so that if you hit someone there is more space between the relatively flexible bonnet and the engine itself to help lessen the impact, afaik.

[XutvJet]

I doubt it's for pedestrian protection. If that were the case, then the M2 Competition would have a larger engine cover. That car uses the same hood as the M235/240 and the engine cover is tiny.

In my opinion, the cover is to keep heat in the engine and help improve warm up. When the N55 came out, BMW said there were new systems employed to improve warm up and maintain heat to help with MPGs and emissions. Insulating components around the motor were noted as components of this system. I believe it. Look at that dense and heavy foam used on the engine cover, on the upper backside of the motor, and the insulation on the hood (Note: the M2 doesn't have the hood insulation, same hood though). The under tray panels also trap heat to some extent as well as improve aero.

There's a downside though. It traps heat and can wreak havoc on the plastic components that reside under the cover and keeps that valve cover and gasket very hot. It also impedes your ability to easily inspect motor for rodent dens.

A while ago I did a silly thing and removed the huge and heavy engine cover so the N55 could cool off and I could see that sweet motor. I installed a BMW 540i V8 valve cover on my N55. The reason I did it was because I wanted a way to cover the injector and coilpack harnesses a bit. Under load, the motor sounds more sporty in the cabin. I do not perceive any addition noise during steady driving or other ugly mechanical sounds when driving normally. I also removed the hood heat shield to help improve air flow in the engine bay. The M2/3/4 do not run the hood heat shield either.

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