# EVAP delete?



## neilneil2000 (Feb 22, 2012)

Has anyone here fully removed the EVAP system from their car? I have been wondering about doing so, but haven't been able to find much information online.


----------



## FNChaos (Nov 30, 2016)

Why would you want to remove your EVAP system? No horsepower to be gained. Car will no longer pass inspection and impossible to sell until repaired / replaced...


----------



## MarksBlackTT (Nov 29, 2016)

Sorry for being naïve, but what is this system? :?


----------



## TT-driver (Sep 14, 2010)

I think it will be a tricky operation. The system has an inbuilt check ensuring it is airtight. And what ever evaporated from the fuel tank is released in a controlled manner when the engine is ready for it.

Since there are no gains, this is not a popular mod. Therefore no information on the web.


----------



## FNChaos (Nov 30, 2016)

MarksBlackTT said:


> Sorry for being naïve, but what is this system? :?


Basically, it is part of your car's emission control system.

It captures hydrocarbon vapors coming off of your gas tank preventing those vapors from dispersing into the atmosphere.

When filling your fuel tank, a carbon filter 'scrubs' the air of hydrocarbon molecules while allowing 'clean' air to vent as it is displaced by fuel. However, under normal operation, it is a "closed" system.

The hydrocarbon molecules that have been captured by the carbon filter can be redirected and burned by your engine. This provides a method of emptying the filter and cleanly disposing of the vapors.

A leak in the system will throw an error code. For example, if you forget to replace your gas cap, your EVAP system will see that as a leak.


----------



## MarksBlackTT (Nov 29, 2016)

Errrrrr, right. Thanks for the response. Kinda think I understand, but much appreciate the response regardless.


----------



## neilneil2000 (Feb 22, 2012)

@MarksblackTT - it recycles the petrol vapours from the fuel tank. Rather than letting them just evaporate into the atmosphere it captures them in a little cannister and then pumps them through the engine at regular intervals

@FNChaos - I think "impossible to sell" is a rather strong term, and I don't know what "inspection" it is you are referring to. In the UK, I wouldn't foresee any impact on resale from doing this, I'd wager 95%+ of people wouldn't even know what this is. Also the USA spec EVAP system is different to the European one due to the stricter regulations state-side.]

@TT-driver - It just seems to be a source of frustration and is a common point of failure, I wouldn't be doing it for performance. I wonder if any of the VW Golf people have done it I shall investigate further.


----------



## TALBOTL (Aug 30, 2017)

MarksBlackTT said:


> Errrrrr, right. Thanks for the response. Kinda think I understand, but much appreciate the response regardless.


I can't confirm as I haven't done it personally, I would be cautious of throwing up the EML light Neil it will definitely be connected in some way to the ECU and fiddling may cause problems, it will then regularly be a case of it going on and off until the system is reconnected.

I also (again can't confirm) believe that the system cannot be fully deleted only partly which again won't do you any favours in regards to throwing up fault codes.

As others have touched upon if it is causing no noticeable issues to your car, you could well end up creating them for nothing.

Either way I hope you manage to find some solid information and can make your mind up based upon that.

LT


----------



## Hoggy (May 8, 2002)

Hi, For the MK1, but it should help.
viewtopic.php?f=2&t=1522354&hilit=evap&start=15
Hoggy.


----------



## FNChaos (Nov 30, 2016)

> @FNChaos - I think "impossible to sell" is a rather strong term, and I don't know what "inspection" it is you are referring to. In the UK, I wouldn't foresee any impact on resale from doing this, I'd wager 95%+ of people wouldn't even know what this is. Also the USA spec EVAP system is different to the European one due to the stricter regulations state-side.


I can't speak to regulations around the world but in the US, tampering with any device considered part of your emissions system is a Federal crime under the Clean Air act.

Of course, some states are more aggressive than others in their inspection and enforcement. 
For an individual, getting caught usually just mean just a 'fix-it" ticket but in some instances fines can be levied. 
Typically though, fines are reserved for businesses that routinely violate the law, (hence the record-setting ~3 Billion dollar criminal fine, on top of the estimated 30 billion dollar repair cost) that VW/ Audi is facing for attempting to circumvent US emissions testing.

States like California require routine emission inspections / smog checks before you can renew your vehicle's registration and during any sale / ownership transfer (and many other states have been adopting California's rules) So yes, messing with your emissions system will have an impact on one's ability to sell the vehicle (at least in the States).

From my perspective it doesn't make sense to remove / tamper with emissions equipment when there is no 'up-side',(even if your Country has no regulations preventing you from doing so). Modern emission systems do not reduce horsepower like they did when they were first introduced. In fact, for the most part they make your engine run more efficiently.


----------



## TT-driver (Sep 14, 2010)

neilneil2000 said:


> It just seems to be a source of frustration and is a common point of failure


Based on my experience on the TT forum, I'd say this is not the case with the Mk2 TT. Just a couple of points to observe:

1 never overfill when filling her up. 
2 Always fully close the fuel cap until it clicks.

Probably the system also needs a good chance to clean itself every now and then. All it needs is a longer drive and the engine automatically sucks up the stored fuel vapours from the charcoal cannister.

The N80 purge valve can suffer from charcoal coming from the cannister. The valve gets stuck and it isn't able to properly close the system. A leak will be detected and you'll get an error code.


----------

