Answer to the Emerald Purge Valve Question...?

[thenick]

Right, I know quite a few people on here have been waiting for an answer to this problem so here's what i've found so far... Maybe we can pool ideas and come up with the best solution.

I had a chat with a friend of a friend who knows a fair bit about fuel tanks and he instantly told me to rip it out and reroute the old vent pipe from the CC to somewhere away from the cabin or engine bay, ideally the rear wheel arch. To prevent fuel escaping through this pipe, a pigtail would need to be put in the end. I then spoke to Dave at Emerald and he agreed that the usual method is to remove them although it is possible that a solution could be found by wiring the purge valve to the Variable Valve output on the ECU possibly though i've yet to look in to this.

So I think i'm going to go with the ripping out method and have so far come up with this... (those with more knowledge than me, please feel free to offer criticism or tell me its a silly idea!)

1. Whip out the CC and plug the old vaccum feed from the plenum (probably by putting some sort of bung in the plenum its self and removing the pipe fitting completely)

2. Locate the vent pipe that connected the tank to the CC and pull it back to the tank.

3. Reroute this pipe to a convenient location under the car (away from the exhaust such as a wheel well (suggestions?))

4. Possibly add one of these instead of putting a pigtail in the pipe: http://www.demon-tweeks.com/products/ProductDetail... - Would this work??
5. Probably add some sort of filter to the end - I was thinking a cheap crank case filter from Halfords (looks like a tiny K&N) to prevent any crap blocking the pipe.


Does this sound sensible? Or does anyone have some better ideas perhaps?


Edit: Just noticed that there's no picture of the Mocal valve on the website, but in the Demon Tweeks book it looks like a small red fuel filter so should be easy to locate and secure

Edited by thenick on Thursday 24th January 19:02

[GreenV8S]

If you have room, then you can take the vent pipe out of the tank on one side and run it across the car to the other side. That ensures that cornering loads can't simply push fuel out of the vent. If you aren't planning to purge the cannister then IMO there's no point having it since charcoal only has a finite capacity to absorb vapour and once it's full it's making no difference (except possibly getting clogged up). Hence, simple vent pipe across the car, up as high as possible. For extra brownie points you could fit an anti-surge flap valve. Any of these solutions would be better than the approach that used to be universal before cats: simply putting a small vent in the middle of the filler cap.