carbon canister

[spink]

To save me chopping one up to have a look does anyone know if there are any moving parts inside one of these?A car I have been working on recently(s4) makes a bizzare sound intermittently and the noise comes from somewhere down that way(bottom of bulkhead/drivers door hinge area).The noise sounds like air passing a valve of similar,if you feather the throttle you can change the pitch of this noise,usually only lasts a second or two.It only happens when the car is moving btw

[UrS4boy]

There is a check valve, item 18 (4A0201096 "bleeder valve", NOTE: BleedER not BleedING)

More N80 and evaporative emissions control info here:

http://forums.quattroworld.com/s4s6/msgs/21014.phtml

[Rusty]

Loads of inormation there, as ever Dave

OT I'll admit but hey ho... Is the carbon canister open to the atmosphere at any point then? If not then where does the air that is drawn through it come from?

Was discussing whether removal of the CC was possible while leaving the N80 in it's normal operation but wasn't 100% sure on the role of the carbon canister... is it efectively a reservoir? Surely an 18y/o CC will be knackered by now and thus effectively useless?

[UrS4boy]

Hey. There is also that "valve", Item 5, at the bottom of the cannister.

[UrS4boy]

Loads of inormation there, as ever Dave OT I'll admit but hey ho... Is the carbon canister open to the atmosphere at any point then? If not then where does the air that is drawn through it come from? Was discussing whether removal of the CC was possible while leaving the N80 in it's normal operation but wasn't 100% sure on the role of the carbon canister... is it efectively a reservoir? Surely an 18y/o CC will be knackered by now and thus effectively useless?

The fuel system is only open to the atmosphere when you remove the cap on the filler. That "Whooosh" sound, that is the slight vacuum resulting from when the N80 opens the system up to the intake manifold when the intake is under vacuum (NOT boost), drawing fuel vapours from the airspace in the petrol/gas tank, into the carbon canister.

Activated carbon can be used and reused for a long time. It is basically a sponge with microscopic pores into which the vapour is drawn in and out, depending on the engine situation. I do not know the life of the carbon.

Personally, as an environmental engineer (retired), I would recommend keeping the system and the N80. It does some good. Raw fuel vapours into the atmosphere contributes to smog, not a good thing.

Now if only those sooty diesel lorries had some kind of emissions control.

[sam80quattro]

ive smashed 1 to see what was in... loads of fecking charcoal lol should have expected it really lol small flakes and lots of them

[s2driveruk]

science and discovery at it's best

[SteveH]

I took the carbon canister off my car to make additional space and reduce weight. There isn't a valve or outlet at the bottom of the unit fitted to the 3B engine. I've just connected the ends of the pipes that went to it together and the N80 in place. I guess it does the same job but minus the carbon?

[UrS4boy]

I took the carbon canister off my car to make additional space and reduce weight.

Space for what? How much weight did you save?

Without the carbon, it is not working as the factory intended.

[Cottis]

I think on a 3B, this is located near the front of the engine bay. Might be making space for mods etc.

Don't really know too much about how it works on the car, but URS4boy sounds knowledgeable reference the workings of this. Definitely learned me something and made me think about an old CQ I owned that always gave off a petrol smell. Various things were checked from exhausts to throttle and fueling issues etc etc. Never did get to the bottom of it. Wonder if that car had one of these Carbon Canisters?

If it did, it would make sense that the activated carbon in it was knackered and if there was a leak somewhere in the system, the smell was coming into the cabin? Dont know but got me thinking so cheers for that.

Reference Activated Carbon granules, they do have a shelf life. Can be bought in a variety of grades and sizes depending on the application or what substance, gas/liquid is being purified. After 18years, it will definitely be almost useless. I guess a car is not running all the time but degradation and time would play a part. I would go as far as suggesting that activated carbon (high grade) would purify smells etc for at least 2 years + but it's ability to continue to be able to perform at 100% will decrease quite quickly after this point.

Fairly cheap to buy (or the quantities needed to fill that canister anyhow) but from what people have said, sounds like it needs to be broken to access.

Definitely dont have the same smell on the S2 (3b) Would that have been changed in it's life? Or was my old CQ sha**ed or maybe suffering a system leak elsewhere. I will never know, sigh!

[UrS4boy]

I think on a 3B, this is located near the front of the engine bay. Might be making space for mods etc.

Thanks. My bad. I thought the S2 would have the evaporative emissions canister tucked into the fender like the 200 20vt 3B and the AAN UrS cars:



But no, it appears to be sandwiched between the coolant expansion tank and the power steering fluid reservoir, attached by two pins to the expansion tank, at least for the 3Bs. (I think the ABY canister is in the fender well)

[SteveH]

Part 1A wasn't on my carbon canister. What would it be for anyway, as it's a sealed system. It looks like a drain pipe?

[SteveH]

Space for what? How much weight did you save?

Without the carbon, it is not working as the factory intended.

Eek! there's lots of things not working as the factory intended on my car

[UrS4boy]

Part 1A wasn't on my carbon canister. What would it be for anyway, as it's a sealed system. It looks like a drain pipe?

Not a drain but a ventilation hose. There should be a bleeder (one-way) valve to let air in (but not out) as well.

[Cottis]

That diagram explains it brilliantly. Thanks (wish my engine bay looked like the one above too ha ha)