Homemade PVC evap chamber

[Irvinec32]

Car came with evap tubes clamped. I wanted to recreate the evap system.

Parts from Lowes and hoses from Amazon.

I know it is bigger than necessary, but I wanted to use off the shelf products that was easy to work with.

Pictures are pretty self explanatory.

Used flat caps for easy drilling. Ground down the print.

Drilled proper size holes for the nipples to be self screw ins. 1/8" fittings.

Mounted. I may change the mount later. I want it as high as possible. I used 4mm lines because they were easier install than 3.5mm. 4mm was easier to find and cheaper too.

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78 convertible

[Tim Donahoe]

Looks good.

I have one issue, though: VW eventually went over to a retangular chamber. I suspect they did this so that the male fittings would remain at 6 and 12 o'clock. That way, the chamber would not turn--like a round one--and end up defeating the fume/fuel gathering and storing design.

In other words, if the male fittings turn so that they are both even with the other, the chamber would not have an inlet and and outlet function.

Did I say that correctly so that you can get my drift?

Still, I think your design would work well if you could manage to keep the tube from turning so that the upper male fittings remain stationary, directly above the lower male fittings.

Good job!

Tim

[Irvinec32]

I did not know that they were supposed to sit at 6 and 12.

I will rotate. Thanks.

Tight clamping will keep it in position.
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78 convertible

[djkeev]

A great idea for sure but keep an eye on it for softening or decay.

PVC is only moderately resistant to gasoline.

You might try version 2.0 using Galvanized Pipe?

Dave
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[wrocek]

Your system has to be able to drain any liquid fuel from the tube you made,
When's hot and you got full tank - fuel expands and seeks way to go, then goes to chamber
After some time it likes to go down to the tank,
In this tube fuel will stay inside, prone to potential leaks, fuel smell, headache...(you name it)
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159 2001 678, FI convertible.
AJ 133584*
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[Bashr52]

[johnnypan]

That or just vent it to the atmosphere...from earth back to earth,the circle of life.

[Irvinec32]

I think the 6 and 12 will definitely help with the drainage.

I bet if the tank is full on a hot day, there will be potential for gas to not drain completely. I will monitor it to see if it gets trapped.

Thanks everyone.
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78 convertible

[DrummerDaveB]

Just dont let a cop see it.

HE'S GOT A BOMB!
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79 SB Vert, in pieces.
Kadrons, SVDA.

[Tim Donahoe]

One last thing: make sure the tube is positioned as horizontal as possible. You pic shows the tube slanted a tad.

And you need not mount it any higher, It's just about where it's supposed to be.

Tim

[Irvinec32]

rotated and leveled.

Johny, I bet whatever gas is not drained back to the tank with be vented to the atmosphere through the carbon chamber. Probably more that the original design.
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78 convertible

[johnnypan]

Its a primitive emissions control system for gasoline vapor,its not that efficient or practical..a 'shepherd hook' in a vent line works just as well with way less crapola..

[CarlIseminger]

I have a '68 where the vent hose goes up from the tank, across the top of the dash (similar to the expansion tank) and then exits out by the spare tire. On a hot day, if I fill my tank to the "tipy top", as the gas expands, it can expand so much, it will push gas out onto the drivewway from the vent tube.

This expansion chamber was another pollution control that had to be added to cars by the EPA so that this gas wouldn't just puddle on the ground. The chamber allows the gas and then drain back into the tank and the temps go down, or the gas tank empties.

Then any fumes that are left are sucked up by the charcol canister.
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1969 VW Beetle Convertible

[Tim Donahoe]

Irvine, the last picture looks great. It's the best owner-made expansion chamber I've seen.

And the fumes from the expansion chamber are merely stored in the charcoal canister--if it's working correctly and hooked up to the air filter and fan. If the system isn't hooked up properly, then you''re just moving fumes from the front to the back--like sweeping the dirt under the rug, so to speak.

I care a lot about the environment, but let's be honest. Even the greenest of us wouldn't not own a carbureted ACVW if we cared that much. My bug, tuned and timed to as good as it gets, pollutes the air 20 times what my daughter's Honda civic does.

So why did I completely re-do my fuel-entrapment system--expansion chamber, hoses, charcoal cannister rebuild, hoses to and from everything?

I did it for selfish reasons. The first, now my wife and daughter will get into the car and ride without complaining about the awful fuel smell. The second, now I can park the car in the garage without fear of a fire on a hot summer's night--where the natural-gas water heater there (or its pilot) will not catch the fumes on fire.

Concerning this last, we all know that some of our bugs are spilling a lot of fumes. Do you really think that fumes, alone, will not ignite in a closed garage atmosphere? They can and they do.

So, I try to keep the fumes in Pandor's Jar, at least as much as I can.

Tim

[Irvinec32]

Is it possible that the car drives better with a evap chamber?

Drove the car today and I got less sputtering than previously.

Could be my imagination, but is it possible that for fuel injected cars like mine, that the high pressure fuel pump works more effeciently when there is aeration? Think of pumping out liquid from a fully sealed chamber, very difficult unless air comes in freely.

Anyone else seem improvements for their fuel injected cars?
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78 convertible

[Irvinec32]

I take it back. Still sputters. Guess I needed to drive a longer distance.
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78 convertible