Correct, left side, hardly possible to fit it wrong, and my guess is it's nothing
to do with heat but protects the electrics from water thrown by the wheel.
General Louvred Engine Under Tray
- Thread starter Toshi 975
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General Louvred Engine Under Tray
Correct, left side, hardly possible to fit it wrong, and my guess is it's nothing
to do with heat but protects the electrics from water thrown by the wheel.
It is almost certainly to do with engine cooling. To understand would require an idea of the airflow used to cool the engine.
The air underneath a vehicle is high pressure, due to the vehicle moving air out of the way to move through it. That would tend to push air from underneath into the engine compartment. A cover with louvres, may instead help air to exit there, as the air pressure reduces as it exits under the rear bumper.
If I remember correctly, the 500 is air cooled? The 600, being water cooled may not need this, although airflow through the radiator is still a design issue.
As an example, the VW Beetle has a sealed engine compartment. When the lid is opened, you should not be able to see the ground, even small holes can cause problems. The cooling air is drawn in through vents, in the engine lid, or on the rear pillars, depending on age, pulled across the top of the engine by the fan, and pushed down over the cylinders, which are below the tray panels. This air then dissipates from under the rear bumper. There have been cases of overheating when plug caps do not seal properly, allowing hot air to re-enter the engine compartment, so gaps in their trays are important.
It appears that the 500 does not suffer as readily as the Beetle, as many owners do not have that trya fitted, but it must help, or, as said above, Fiat would not have borne the expense of it.
The air underneath a vehicle is high pressure, due to the vehicle moving air out of the way to move through it. That would tend to push air from underneath into the engine compartment. A cover with louvres, may instead help air to exit there, as the air pressure reduces as it exits under the rear bumper.
If I remember correctly, the 500 is air cooled? The 600, being water cooled may not need this, although airflow through the radiator is still a design issue.
As an example, the VW Beetle has a sealed engine compartment. When the lid is opened, you should not be able to see the ground, even small holes can cause problems. The cooling air is drawn in through vents, in the engine lid, or on the rear pillars, depending on age, pulled across the top of the engine by the fan, and pushed down over the cylinders, which are below the tray panels. This air then dissipates from under the rear bumper. There have been cases of overheating when plug caps do not seal properly, allowing hot air to re-enter the engine compartment, so gaps in their trays are important.
It appears that the 500 does not suffer as readily as the Beetle, as many owners do not have that trya fitted, but it must help, or, as said above, Fiat would not have borne the expense of it.
I respect the work of engineers, and I'm convinced that they do not create parts willy-nilly, even if the reasons are not always obvious to us users.
In this case, though, the tray covers at most 15% of the bottom area of the engine bay, and well clear of heat-producing areas, from crankcase to exhaust. It does shield the dynamo and regulator from the nearby left wheel. The louvres help dissipate a potential pocket of hot air, but that's not the tray's main function here.
Not owning a 600 or Beetle, I would not presume to comment on those.
The Fiat 500 doesn't rely on having a sealed engine compartment and anywhere additional where hot air can exit would be welcome.
As Dave Toshi 975 has shown, the latterly developed 126 undertray offered louvres aligned to allow air to exit; this pushes the argument towards the idea that its main function is for protection.
On my 900 van, which is a successor to the 600, there is a need for the engine bay to be almost completely sealed by undertrays and cowlings. This is because the hot air is positively extracted through a radiator to exit under the vehicle. There is a need to ensure that heated air is not recycled.
As Dave Toshi 975 has shown, the latterly developed 126 undertray offered louvres aligned to allow air to exit; this pushes the argument towards the idea that its main function is for protection.
On my 900 van, which is a successor to the 600, there is a need for the engine bay to be almost completely sealed by undertrays and cowlings. This is because the hot air is positively extracted through a radiator to exit under the vehicle. There is a need to ensure that heated air is not recycled.
The 600 doesn't have under trays, it pulls air in via a thermostaticly controlled flap, pulls it through the radiator and actually expels the air back into the engine bay where is should escape through the engine lid louvres.
The 850 has undertrays which are a vital part of the cooling system as it pulls air in via vents in the rear and top panel and expels it out under the car. If the trays aren't present, especially in traffic hot air can re-enter the engine bay and lead to overheating.
