Charcoal Canister Removal - Anyone done it?

[onequick325]

I'm tracking my car strictly and want to remove the charcoal canister. Anyone done it? If so, how did you cap off the line or what kind of breather did you put on the end of it?

Thanks

KK

[Flip_Side_the_Pint]

bump, I'd like to know the same....

[bmwman91]

Well, it probably weighs about 3lbs which inthe long run is not a whole lot. It would make some room down there, for what I do not know. I have contemplated removing it as well back when I was looking for ANY way to reduce weight, but I am pretty sure it serves an important function. I BELIEVE it filters residual gas fumes from the PCV system helping to reburn them, saving fuel economy & the environment. Since it is a part of the PCV system, you would not want ot have it left open to the atmosphere. Maybe put a small filter inline, or just connect the ends.

[Beau B]

Well, it probably weighs about 3lbs which inthe long run is not a whole lot. It would make some room down there, for what I do not know. I have contemplated removing it as well back when I was looking for ANY way to reduce weight, but I am pretty sure it serves an important function. I BELIEVE it filters residual gas fumes from the PCV system helping to reburn them, saving fuel economy & the environment. Since it is a part of the PCV system, you would not want ot have it left open to the atmosphere. Maybe put a small filter inline, or just connect the ends.

That is what it does. I personally would not remove it, but that is just me.

Beau

[ecpreston]

it's purely an emissions thing and isn't tied in with a PCV system. At least in the case of E30's, there's an inlet to the canister that comes from the fuel tank (actually, a secondary expansion tank), and an outlet into the throttle body or intake. The charcoal soaks up fumes when the car's not running or just at idle, and vents them back into the intake when running. Most of our charcoal canisters aren't even working anyway by now, it's supposed to be replaced now and then, and who's done that?

If I was going to remove it, I'd cap off the hole in the intake or TB, and install some little filter like one of these on the open line coming from the tank. I'm sure there's something to be found at any local autoparts store that would do the job for cheap.

[Flip_Side_the_Pint]

what about using some sort of catch can device?

[cdk4219]

The charcoal cannister is not only an emmissions device, but a needed vent fo rthe fuel tank. It is also an air gap inline device, that doesnt allow liquid to pass through it. Capping the line will produce excess tank pressure, removing it and leaving the line open to the atmosphere will vent the gas fumes (or possibly raw fuel in extreme cases when the tank is full to the tor) wherever the open line is, in this case the engine compartment, which in turn will leave you and your passengers to smell those lovely fumes or again in a worse case cause a fire under the hood( highly unlikely but either case isnt pleasant) Lastly replacing the cannister with a crankcase filter is about the same as leaving it open to the atmosphere, and hooking it up directly to the vacuum source via the evap solenoid would run the risk of vacuuming up raw fuel into the intake, worse case hydrolock. If you are going to track it and would like to lose the cannister and related lines and hardware, I would suggest removing the check valve assembly from the gas cap (or drilling a small hole in it for venting), and capping the tank vent line at the tank and removing the tubing going to the front.

[epj3]

The charcoal cannister is not only an emmissions device, but a needed vent fo rthe fuel tank. It is also an air gap inline device, that doesnt allow liquid to pass through it. Capping the line will produce excess tank pressure, removing it and leaving the line open to the atmosphere will vent the gas fumes (or possibly raw fuel in extreme cases when the tank is full to the tor) wherever the open line is, in this case the engine compartment, which in turn will leave you and your passengers to smell those lovely fumes or again in a worse case cause a fire under the hood( highly unlikely but either case isnt pleasant) Lastly replacing the cannister with a crankcase filter is about the same as leaving it open to the atmosphere, and hooking it up directly to the vacuum source via the evap solenoid would run the risk of vacuuming up raw fuel into the intake, worse case hydrolock. If you are going to track it and would like to lose the cannister and related lines and hardware, I would suggest removing the check valve assembly from the gas cap (or drilling a small hole in it for venting), and capping the tank vent line at the tank and removing the tubing going to the front.

Plus I believe you'd get a check engine light? Isn't there a little sensor attached to the charcoal canister? I don't remember, it was 6 months since I replaced mine. Maybe i'm thinking of the sensor that goes to the bottom of the throttle body (not the throttle position sensor - the one with the short hose)

[cdk4219]

Possibly on an OBD1 or OBD2 car, as most of them have fuel tank pressure sensors, but I dont have one on the 91.

[ProPhotog]

That is what it does. I personally would not remove it, but that is just me.

Beau

I totally agree. What could happen, and has at least on some GM's I've seen, is it can eventually compress the fuel tank especially in hot weather with the fume build-up

[ecpreston]

I totally agree. What could happen, and has at least on some GM's I've seen, is it can eventually compress the fuel tank especially in hot weather with the fume build-up

I don't understand. I don't think anyone is talking about capping the line, defeating the vent from the fuel tank. That WOULD be dumb.

[onequick325]

I appreciate the feedback by everyone. Let me clear up why I'm interested in removing it. I understand the function of the canister, and by all means want to vent it correctly. Yes, into the atmosphere, shame on me. If you look at the canister from the bottom of it, it's vented as well.

There is a purge valve underneath the throttle body that hooks up to the canister which puts fuel vapors into the intake airflow after the AFM or MAF if your lucky. This vapor will condense in your manifold. Therefore two things that bother me, considering I want every possible ounce of power. The first is you have essentially UNMETERED air coming in the throttle body which are harder to ignite. Secondly, it mucks up your intake manifold(mine is off, I know). Two things you need for good ignition, dry air and you want it to flow as best as possible. The moisture sticks to the walls causing a very slight(real slight) build up. It does impede the flow of air to some degree. Considering I'm getting my intake extrude honed, I don't want to take away from that pretty work.

[turningermanese]

Anybody think that we're exaggerating just a WEE bit about this? The EVAP system isn't some horrible power-robbing device that will ultimately kill off 50 Hp. It's a pretty benign emissions control device. If you really wanted to disable it, I'm guessing you could just unplug the connector under the throttle body that operates the purge valve. And if I'm not mistaken, the check valve that doesn't allow liquid gasoline flow from the charcoal cannister is located back at the tank. So, in theory, you could just disconnect the line coming from the tank at the cannister and throw a breather element on it. Personally, I would just say f-it and leave it alone, but that's just my $.02

[cdk4219]

I appreciate the feedback by everyone. Let me clear up why I'm interested in removing it. I understand the function of the canister, and by all means want to vent it correctly. Yes, into the atmosphere, shame on me. If you look at the canister from the bottom of it, it's vented as well.

There is a purge valve underneath the throttle body that hooks up to the canister which puts fuel vapors into the intake airflow after the AFM or MAF if your lucky. This vapor will condense in your manifold. Therefore two things that bother me, considering I want every possible ounce of power. The first is you have essentially UNMETERED air coming in the throttle body which are harder to ignite. Secondly, it mucks up your intake manifold(mine is off, I know). Two things you need for good ignition, dry air and you want it to flow as best as possible. The moisture sticks to the walls causing a very slight(real slight) build up. It does impede the flow of air to some degree. Considering I'm getting my intake extrude honed, I don't want to take away from that pretty work.

The air going into the intake Via Evap isnt astually unmetered, as the ECU figures this in the mix when the EVAP solenoid is open. WHat happens when you unplug the solenoid, and the ECU calls for purge and thinks the solenoid is open when it is unhooked? Either way removed or left in place it wont make as much difference. If you want to go faster eat a couple less french fries at McDonalds before the session. The weight savings will probably be a greater advantage than the charcoal can loss.

[uberpanzer]

Not the same engine (nor chassis), but I've removed mine from the e21. My M10 seems to be running fine without it. But this was out of pure stupidity more than anything else. In the e21 it is bolted to the bottom of the battery tray (wonderful place for it! ). I have relocated my battery to the trunk and have an intake tube running through the area where this stuff HAD been. So, I zip-tied the cannister to the front bumper shock (seemed good! ), and made sure all the likes were out of the way of moving parts (visually). Well, I SHOULDA zip-tied the lines too, since once I started tossing the car in turns, they moved a little bit and ended up in the path of the alternator. The fins on the alternator cur through anything that got close, making it so that I HAD to remove everything one night on my way home (once it was making all the racket under the hood). I have not capped anything off, but really should, esp since there IS A very strong gas smell if te car has been sitting for too long in the sun.

[smittyM98]

Reviving this 20 year old thread… what’s the benefit of using a filter in the open line coming from the tank? You’d still smell the fumes anyway..

[Mikealwa]

I did this just to keep crud out of the line and to keep it protected. Probably unnecessary and doesn't even function this way. Actually since I changed my tank I can't even remember what I did with the vent line 🤷🏼. I have no issues.

[mimmzy37]

Reviving this 20 year old thread… what’s the benefit of using a filter in the open line coming from the tank? You’d still smell the fumes anyway..

Holy shit this thread is literally 20 years old. I was 4 years old when these guys were talking about this originally.

Anyways, I’m going through this process now on my m42 e21 swap. Right now the vent line on the e21 is loose, the old charcoal canister is gone and I’m wondering what to do, and if anyone has any tips. I’m either gonna cap off both ends (intake end and the open fuel line, not sure if this is disastrous though), route a one way air valve in between the chassis line and the intake line so the vapors get put through the intake again (also not sure if this is gonna cause problems) or just buy the correct e36 m42 charcoal canister but really only wanna do that if it’s completely necessary, like if the engine harness has a plug for the charcoal canister or something. Not sure but I’ll update if i figure it out