Author Topic: Evap canister hookup  (Read 1875 times)

Offline KJMason

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Evap canister hookup
« on: August 19, 2014, 03:20:15 AM »
I've got a 71 TA that originally had a charcoal canister that was removed and I'd like to add one back (wife has too many complaints about the gas smell, lol).  The can for this year had two ports, one from the fuel tank and the other going to the carb but my engine is a mix with a 72 455 block, Edelbrock heads and manifold, and a 70 Q-jet.  I guess I can rig this most anyway I want but my question is which carb port is best?  Timed, manifold, PCV, EGR?

Offline Ethan1

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Re: Evap canister hookup
« Reply #1 on: August 21, 2014, 12:27:10 PM »
I've got a 71 TA that originally had a charcoal canister that was removed and I'd like to add one back (wife has too many complaints about the gas smell, lol).  The can for this year had two ports, one from the fuel tank and the other going to the carb but my engine is a mix with a 72 455 block, Edelbrock heads and manifold, and a 70 Q-jet.  I guess I can rig this most anyway I want but my question is which carb port is best?  Timed, manifold, PCV, EGR?

 Sorry I cannot be of much help, but have you tried posting the same question over in the Performance Years forum website? There is a lot of Pontiac guys on here as well, including Cliff, so there will be some help soon. :D
Ethan

1972 Chevelle

(oo______oo)

Offline caffeineracer

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Re: Evap canister hookup
« Reply #2 on: September 25, 2014, 04:15:27 PM »
So I recently did this on my qjet. Mine is an E4ME, but it shouldn't be too different. On mine there is a port pointing out the back out of the airhorn (the top). This was a fresh air feed for the EGR, which I don't run anymore. It doesn't really pull much of a vacuum, but it is enough to slowly decant off the fuel vapor from the canister while the engine is running.

On the factory setups there was complicated temp controlled vacuum systems that determined when the canister would purge. It makes for a very cluttered engine bay. The setup I described has been running on my car for about 1000 miles and I haven't had any issues with it best I can tell.

If you don't have that port on the back of your carb I would say to definitely run it to a ported vacuum source not manifold. Also I should mention that I put a check valve inline of the hose going from the canister to the carb (pretty much I went to autzone and found a PCV valve that required very little pressure to open the valve and that had barb fittings pretty close the the hose size I used).

Hope that helps.