Remove charcoal canister?

[RyanH]

Hi. Having a tidy up of the trunk on my 1970 911T and wondered if the charcoal canister can be removed and the lines plugged? I seem to remember reading somewhere these were an early attempt at emissions and are not really considered to be of use any more? Anyone done this? Cheers...

[RichardNew]

I just spent money to buy one and put it into my 1973. I can't answer any question about how they work but I know you have to pay decent money to buy one today. I don't intend to make mine operable but the car does have to look correct.

Is that a little sick?



Richard Newton
Original May Not Be Original

[javadog]

The charcoal canister controls evaporative emissions. It's not the same thing as exhaust emissions control, so to say it's an early attempt at emissions control and that it is not needed is incorrect.

For a long time, ROW cars did not have this. So, it's technically possible to remove it and you could revert to the ROW system for fuel tank ventilation. Doing so, you'll notice more fuel smell in your garage.

JR

[ISpeed2day]

and if it was located in the front of your car but you remove it, you will want to run a small line from where it was to the back of the car so you don't smell gas going down the road.

don't ask me how I know... and someone either buy my GT or give me a good reason why nobody has.

[RyanH]

Thanks for the feedback. I have a ROW 911, what is the system used for ROW? Just a question and I'm leaning towards just leaving it in, but would plugging the lines not send any fumes back to the engine bay and out the grille?

[javadog]

I have no idea what system is in your car. Could have been added somewhere during its life. I've had a few ROW spec 911s and none of them have had a charcoal cannister. Generally, the tank vented to the overflow tank in the LF fender, then to an open line that ended behind the front bumper. Nothing went to the rear of the car.

Find a diagram for your year and understand what you have now, before you change anything. There's no substitute for looking at exactly what you have and understanding it before messing around with it.

JR

[ossiblue]

Originally Posted by RyanH

Thanks for the feedback. I have a ROW 911, what is the system used for ROW? Just a question and I'm leaning towards just leaving it in, but would plugging the lines not send any fumes back to the engine bay and out the grille?

Post a picture of your set-up as that will let us all know what has been added to your ROW car.

As stated before, the canister is for fumes from fuel evaporation and is passive, however it is also part of the ventilation system for the tank and plugging the hoses could cause problems as the tank will now not be ventilated properly and a vacuum could be created inside the tank itself. If you have no problems with the system now, I'd suggest you leave it alone and do not plug any hoses.

Again, without seeing your setup we don't know how it is plumbed. Typically, the canister has a large and small port at one end, and a single large port at the other. The two port end is for a hose that carries fumes (small port) and a hose from the fan shroud (large port) that blows air into the canister. The single port end is for the hose that carries the fumes back to the intake. If you have no hoses running back to the engine, then be sure the single hose end of the canister is connected to a line that ends somewhere outside the trunk. If there is no large hose at the two port end, then you could plug that port.

[47silver]

my evap hose running in the tunnel was plugged and made filling the gas tank very dificult.. also i noticed that the gas cap was almost impossible to remove which meant a very high negative was being placed on the gas tank which may lead it to collapse.
i welded 2 coat hangers together to clean out the line.
the theory of the cannister i think.. is that when the car is shut off the gas fumes accummulate in the cannister. When the engine operates the fumes are then pulled in to the engine via the vacuum line. if you disconnect the cannister wyou will vent gas fumes to the atmosphere which may not a be a good thing in a closed garage.

[frankc]

I have a '73 RoW T project that was mostly stripped when I purchased it, so I also will need to determine what is correct for evaporative emissions in '73 for RoW cars. It did have the small charcoal canister under the left cowl area, but everything else is gone.

I'll research PET to see if that provides any clues, but if anyone that owns a '73 RoW car could let me know what is installed, that would be great.

[javadog]

Usually a ROW tank vents to an expansion chamber, then to the atmosphere. In the later cars, the expansion chamber is behind the left headlight bucket, in the earlier cars I think it was under the cowl. I know where all the lines run on the later cars but I don't know where the earlier ROW cars vent the fumes to the atmosphere.

JR