Carbon canister plumbing

[tmoretta]

I am using a Miata fuel vapor/carbon canister instead of the very large and heavy Subaru unit. The Miata canister has three ports: two on one side (medium sized marked tank and a small one), and one larger port on the other side. I am thinking that the one marked tank should be plumbed to the FFR fuel tank vent, but I don't know about the other two. I have eliminated any connections to vacuum (intake). Any experience/ideas?

[AZPete]

I've got my Miata vapor tank with the upper "tank" port to the fuel tank and the bottom port has a tube that just hangs down by the frame. The smaller port on the upper side is not now connected to anything. So far, I have no gas fumes in the garage and no problems after a few go-kart miles. Like you, I don't have the OE vapor recovery system. Unless somebody tells me a better way I'll leave it as is.

[tmoretta]

I've got my Miata vapor tank with the upper "tank" port to the fuel tank and the bottom port has a tube that just hangs down by the frame. The smaller port on the upper side is not now connected to anything. So far, I have no gas fumes in the garage and no problems after a few go-kart miles. Like you, I don't have the OE vapor recovery system. Unless somebody tells me a better way I'll leave it as is.

Do you know, in fact, that the "tank" port is mounted up? Is that the orientation in the Mazda?

[Jaime]

The other port is to prevent the canister from being saturated with fuel and then not performing it's job. When the ECU feels like it, it activates the purge solenoid, which opens a pathway from the canister (that extra connector) to the intake manifold. All the fuel vapors get sucked out of the charcoal and burnt leaving the charcoal ready to absorb more fuel vapor.

Run that port to the purge solenoid. The other side of the purge solenoid should be connected to the manifold. If you don't want to hook it up, plug it. Leaving it open is like drilling a hole in the canister.

[cobratech]

One line goes to the tank ,one goes to the purge valve witch is mounted in the engine compartment the last goes to a vent valve which is usually mounted in the tank area

[Jaime]

The vent valve on a WRX is mounted on the tank itself. The only thing it's used for is a self-test that the ECU does every once in a while. I doubt anyone building an 818 will go through the trouble of keeping it. The line that should go to the vent valve can be just left pointing down with the end open.

[tmoretta]

Yes, but other than the tank port (which is identified), which of the other two ports are which?

[Jaime]

The one next to the one marked TANK is the purge connection. See here (http://www.mx5nutz.com/forum/index.php?showtopic=15120&hl=charcoal).

[jaw777]

Anyone determine a good place to mount the charcoal canister? The OEM is obnoxiously large and I don't want to buy another. And are there any requirements like it has to be mounted above or below the tank valve?

Thanks

[Goldwing]

On the wrx it is mounted low at the rear corner. I did the same. I mounted the end with two feet along the frame rail with a 5/8" or so spacer. This pointed the other end out into the open space towards the rear left wheel. I used a bar stock piece to fashion a bracket in a triangular mount. "Tank" to the tank, "vent" to a filter, and purge to the purge line foregoing the valves other than the intake mounted purge valve. I need to look into the purge setup with none of the other valving in place. If anyone has any input there, I'd love some insight! I ran the vent line high on the way to the canister, and mounted the vent end filter high above the filler neck to prevent syphoning if I overfill the tank. I'm considering an extra vent line to the top of the filler neck after hearing of issues filling the tank. I'll probably install a tee at the rollover valve, the rollover valve to the canister, the other to the filler neck a little above the fuel nozzle reach if possible.

33696

The pic shows the canister placement. I reworked the lines a little after taking this pic.

[Mechie3]

Goldwing, any reason you kept the air pump?

[Goldwing]

Goldwing, any reason you kept the air pump?

Didn't have a cobb AP to delete the resulting code which I understand throws the car in limp mode, or the gaskets to seal it off preventing back flow. I wanted to go kart! This was the path of least resistance. My engine was in such good condition, I didn't really touch it other than a timing belt and oil change. I'll do more engine work over winter, the air pump might go then, along with the TGV deletes, parallel fuel setup, and maybe a larger turbo. I go back and forth on the turbo decision. The power to weight ratio is very healthy once tuned. I don't want it to be crazy enough my wife gets hurt trying to drive it. The performance is all theoretical until I get behind the wheel. Makes it hard to decide. So, really, I just wanted to go for a ride, a crude mounting was the easy way out.

[Mechie3]

If you do delete the airpump don't buy the block off plates that are $30+. Subaru has some for the tribeca that are $3. Google should help you find them.

[tmoretta]

In your canister photo, it looks like one of your trans. cables is routed outside of the left rear coil over. Is this normal? What about fender liner aluminum etc.?

[Triathletedave]

Goldwing, would it be possible for you to post a few more pics of your vapor canister plumbing lines? I'd love a closer look at how you routed the lines to the tank, intake, and vent. Thanks.

[Goldwing]

I can't get the best pics now, and still didn't get around to extending the line between the tank and vent a little higher to prevent any overfill issues, but here's a few:
Two lines follow the frame to the left cyl bank, 1 back down to the tank, 1 bends up to the fuel connector area.
34092
Shows the vent line. Planning a better mount as the aluminum gets in.
34093
Just routed the vent lines back to the frame, then up over the left cyl bank.
34094

[MrDude_1]

If you do delete the airpump don't buy the block off plates that are $30+. Subaru has some for the tribeca that are $3. Google should help you find them.
The part number is 14754AA050.
threads with info and pics:
http://forums.nasioc.com/forums/showthread.php?t=2371781
http://www.subaruforester.org/vbulletin/f87/cheap-air-pump-delete-116571/

[Jaime]

Anyone determine a good place to mount the charcoal canister? The OEM is obnoxiously large and I don't want to buy another.
Thanks
Here's what I did:

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20141005_191212_zpszoyjbykt.jpg

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20141005_191410_zpsmawpjou2.jpg

It's from a Yamaha scooter - cost me about $20 on eBay.

[dougkirkbride]

Working on fuel lines and evap stuff today and still a little confused. if I plug the evap line (one of the three coming from the top of the motor) and remove the solenoid and valve and plug all those lines on the manifold then where does my carbon canister go? on the tank vent line? I am looking for a simple way to do this with one of the homeade charcoal canisters.

or

if I leave the evap system then where does that evap line coming from the top of the motor go to? the carbon can? so this carbon can would have two inlets and one outlet (essentially a hose to atmosphere) the inlets coming from the motor evap line and the tank vent line?

[dougkirkbride]

if I leave the evap system then where does that evap line coming from the top of the motor go to? the carbon can? so this carbon can would have two inlets and one outlet (essentially a hose to atmosphere) the inlets coming from the motor evap line and the tank vent line?


this is a schematic of what my homeade carbon can plumbing would look like. does anyone see an issue plumbing it like this? the evap line (when the engine tells it to) would pull air up thru the line that says to atmoshere. i would think it would be the path of least resistance when comparing to pulling it from the tank vent line.

39700

[STiPWRD]

Have you researched the stock emission system? One issue I can see is the evap line from the motor may pull too much of a vacuum inside the canister and implode your gas tank. Make sure you fully understand the stock emission system and its functions or just plug the motor evap lines and vent the vapor canister to atmosphere.

[tebriel]

I'm pretty sure you can delete the air pumps without codes, something about cutting the plug off the pumps and leaving it plugged into the harness?

[Goldwing]

Re reading this thread, I wonder if plugging a fitting to the purge line and drilling a small hole through it would allow the purge line to work, while robbing it of any ability to collapse the tank. Working like a restrictor pill from the turbo control lines, it would hinder the flow of air through that line never having the chance to get ahead of the open air vent.

[iblackwe]

Here's what I did:

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20141005_191212_zpszoyjbykt.jpg

http://i871.photobucket.com/albums/ab273/jaime398/818%20Build/20141005_191410_zpsmawpjou2.jpg

It's from a Yamaha scooter - cost me about $20 on eBay.


How does this work for you? Is it large enough to handle the demands of the motor so far?

Thanks,
Ian