[tylerhart_21]

This is more of a curiosity question. Why do the US cars have the charcoal filter while the euro cars don't?

[Biginboca]

Originally Posted by tylerhart_21

This is more of a curiosity question. Why do the US cars have the charcoal filter while the euro cars don't?

US Emissions Laws

[tylerhart_21]

I can see that will California and there laws. So the main reason they use it is to stop these particles from escaping from the intake. (When you turn off the car)

[Brian86]

The charcoal canister is between the fuel tank and the atmospheric vent.

It collects gasoline fumes to prevent them from escaping to the atmosphere.

The vapor side of the fuel system is then subsequently connected to the intake manifold, so when running the engine pulls some air in through the charcoal canister and into the intake for combustion.

This purges the fuel out of the charcoal canister for pretty much infinite reuse.

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Seriously? euro cars don't have charcoal canisters and fuel evap systems at all? The fuel system just vents straight to atmosphere? That's wild.

That would have saved me a lot of problems on my e36.

[The Nightman]

Originally Posted by Brian86

The charcoal canister is between the fuel tank and the atmospheric vent.

It collects gasoline fumes to prevent them from escaping to the atmosphere.

The vapor side of the fuel system is then subsequently connected to the intake manifold, so when running the engine pulls some air in through the charcoal canister and into the intake for combustion.

This purges the fuel out of the charcoal canister for pretty much infinite reuse.

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Seriously? euro cars don't have charcoal canisters and fuel evap systems at all? The fuel system just vents straight to atmosphere? That's wild.

That would have saved me a lot of problems on my e36.

The charcoal filter in question is in the N51/N52 NA spec airbox. It's supposed to capture unburned gas fumes that escape from the intake into the atmosphere.

I believe it's for the N51 to meet SULEV II but all N52s got it for whatever reason: https://www.e90post.com/forums/showthread.php?t=52608

There might be some power gains if you delete it: