i was looking in the wheel arch on my 1992 1275 mayfair last night i saw what i can only guess is a charcol canister. how does this work and is it worth leaving in when i rebuild my mini.
charcol canister
Started by
andywaller
, Apr 14 2005 02:47 PM
5 replies to this topic
#1
andywaller
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Posted 14 April 2005 - 02:47 PM
#2
Bungle
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Posted 14 April 2005 - 04:17 PM
is what your looking at the fresh air vent for the heater ?
#3
Dan
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Posted 14 April 2005 - 07:06 PM
Yes you have to leave it in place. While it is not on the MOT it is part of the construction and use (motor vehicles) regs for your car. And your ECU and emmissions systems expect it to be there and may not work properly without it.
It is designed to stop your car from off-gassing fuel when it is not being used. The vent line from your fuel tank does not run directly to atmosphere, it runs through the charcoal canister and any fuel vapour which may try to escape from the tank through the vent line is absorbed into the carbon on it's way through the canister. The carbon is capable of absorbing many times it's own mass in fuel. Then when the ECU detects that the engine has reached operating temperature a purge valve is opened into the inlet manifold so that the engine draws some of it's air through the canister which has the effect of pulling the fuel back out of the carbon and it is burned off in the engine. It's a harmless little system which doesn't cost you any real power output or take up any space so it's best to leave it in place, unless you are intending to fit an older engine which won't understand how to use it in which case dump it.
By the way, if you dump it remember that the canister is full of activated carbon powder (not activated charcoal which is different altogether) which is just about the most corrosive thing on earth. Don't break it open, don't play with the powder, it will take your skin off. And you can't just throw it in the bin as it is hazardous waste.
It is designed to stop your car from off-gassing fuel when it is not being used. The vent line from your fuel tank does not run directly to atmosphere, it runs through the charcoal canister and any fuel vapour which may try to escape from the tank through the vent line is absorbed into the carbon on it's way through the canister. The carbon is capable of absorbing many times it's own mass in fuel. Then when the ECU detects that the engine has reached operating temperature a purge valve is opened into the inlet manifold so that the engine draws some of it's air through the canister which has the effect of pulling the fuel back out of the carbon and it is burned off in the engine. It's a harmless little system which doesn't cost you any real power output or take up any space so it's best to leave it in place, unless you are intending to fit an older engine which won't understand how to use it in which case dump it.
By the way, if you dump it remember that the canister is full of activated carbon powder (not activated charcoal which is different altogether) which is just about the most corrosive thing on earth. Don't break it open, don't play with the powder, it will take your skin off. And you can't just throw it in the bin as it is hazardous waste.
#4
P91MER
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Posted 14 April 2005 - 07:37 PM
ahhhh.. i have ALWAYS wondered what the canistor tank actually does!!
I knew it was something to do with oxins, and emmisions etc.. just wasn't sure how it worked!!
cheers Dan, i can now sleep at nite!
Rich
I knew it was something to do with oxins, and emmisions etc.. just wasn't sure how it worked!!
cheers Dan, i can now sleep at nite!
Rich
#5
andywaller
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Posted 16 April 2005 - 03:51 PM
oh right i thought it was something along those line only one thing its running a carb so it aint got an ECU 
#6
Dan
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Posted 16 April 2005 - 07:46 PM
Then the system which opens the purge valve is run by a thermic vacuum valve thingy which is in the thermostat housing. On a carb engine it may be worth considering removing it as it is fairly hard to calibrate for the change in mixture strength when the valve opens without electronic control. If you are tuning for maximum power then this may hurt your output, but in most cases the system is fine left where it is (and less hassle than getting rid of it too!).
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