"Ventectomy" and filling at the pump

[jimbof]

Considering a ventectomy on the car, as the extra diesel would mean I can fill up on a Monday morning on the way to work (55 mile journey) and have enough diesel to make it all the way through to the next week.  That way I'd never be parking up with the expansion area full of diesel (not that it makes much difference on diesel anyhow).

 

My question is - at the moment if I want to put diesel in the expansion area I press the nozzle onto the vent as I'm filling the last bit (so the nozzle isn't all the way home).  I don't like doing this as it is a little risky.  I notice that it takes a while for the diesel to disappear down the hole when filling like this.  So I wonder if with the ventectomy done I can fill up the expansion area with the pump nozzle all the way home, or will the pump cut-off kick in if I don't have the nozzle withdrawn a bit from the neck?

 

Hope my question makes sense.

[dieselV6]

I have ventectomized all 3 Skodas I had and most of the time fill up till diesel settles just below the metal lip of the filler neck. Expansion has never been a problem, I suspect the plastic tank expands as much as diesel. It is more of a petrol issue, but this mod is unworkable, illegal and dangerous for petrols, while providing nice extra capacity for diesels.

 

You can keep the nozzle almost all the way in, but you still need to fill the last 5-7 litres slowly, while diesel fuel in the tank foams off. No way around this other than finding a station dispensing fuel with anti-foaming additives. Non-foaming fuel takes only about 1min shorter though.

 

Nozzle all the way in (as in pressed in) results in nozzle cutting off at full flow anyway, at least on my cars, so I keep it about 1/2in from the full in position. Ventectomy is still much safer against spills than pressing the vent valve, as the nozzle 1/2in from max is still quite deep and will cut off once fuel hits it back.

 

On the Superb, you can access the vent valve under rear wheel well liner I think, though I might be wrong on this as the last time I looked there was 8+ years ago. Flat screwdriver to press a catch and push out, then remove the valve , put the plastic assembly minus the valve back together and push it back in. Really simple.

Edited 18 September, 2014 by dieselV6

[jimbof]

Mine fills OK with the nozzle all the way in at most forecourts (I was at one the other day which wouldn't fill more than a couple of litres without withdrawing slightly).

 

Might give it a go this weekend if I get a few minutes.  Thanks!

[jimbof]

Ventectomy 'ected.  

Very quick to do, all without going under the car or disturbing the wheel liner.  10 minutes by torchlight.

Great set of photos here:

http://pics2.tdiclub.com/gwillie/VW/ventectomy/index.htm

Single T20 torx, pull out the fuel filler flap and rubber splash catcher, and then as you say press the catch and push out the vent, and re-assemble.

The only thing I reckon might be tricky is if you wanted to put the valve parts back in.  The stem of the valve is the easiest thing to use to push the valve out, without the valve in place I think it might be necessary to have the wheel liner out and prise it from the back on the flat edge of the vent assembly.

 

Worked well - I was two notches from empty on the gauge and still got 57litres in...

[Danny 57]

Good luck to you guys who want to do it but I find at Tesco's that does not foam I can get in 56-57 litres in when "empty" so that I really could not be bothered just for a litre or two at the most and I know when it shows no more miles I have done a further 20 - 30 to get in 58 litres at best.

Btw that was for my first Superb a mk 1.

Edited 18 September, 2014 by Danny 57

[dieselV6]

Forgot that on older cars you could also do it via filler flap, but as I said it was 8+ years ago.  I'm pretty sure on the Roomster undoing the wheel well liner is the more sane way though as space is very limited.  

 

Difference vented to not vented on 2006 Mk1 is 62l stock, 69l vented, so 7l, makes biggest difference to me on autobahn as I can choose refuelling point in a cheaper country than Germany, depending on direction for up to 30% saving of fuel bill, and when driving at speed I can travel ~20min longer between stops. Not having to visit petrol stations as often helps also in the UK.

 

Earlier Superbs could gain possibly larger amount ,could be 9l if the tank has similar layout like Mk4 Golf/Mk1 Octy. Looking at my cluster where 2 notches are about 1/4 of nominal tank capacity, I guesstimate from numbers provided that 2 notches from empty with 55l nominal tank and 57l added in afterwards works out to ~69l, similar to later cars unless your fuel indicator is different and 2 notches mean something else. 

[jimbof]

Sounds about right.  Pretty sure I'll be good for the whole 69L - I never run it past zero anyway (apart from the one time I left the car on zero overnight and then did 30 miles on dual carriageway before realising... I reckon I was on fumes at that point.)

[jimbof]

This looks to have been a complete success for me.  I've got to the end of the week, done all my commuting driving (620 miles), and the onboard computer is still showing 100 miles range (almost two notches left!), which will do me my little bit of weekend driving until filling up Monday morning.  Yay!

[Kazimir80]

Wow, I am really interested in this, since on my journeys over germany I emtpy the tank within day. But I am not sure about the translation from English (not native speaker). Probably, are you able to get some pics how it is done on Superb mk2?

 

thanks a lot

K.

Edited 12 November, 2014 by Kazimir80

[dieselV6]

Link in post #4 has a detailed guide with photos of each step, you need to remove the white part (shown with arrow here), disassemble it and remove the innards.

 

Access is either through the fuel tank flap as shown in photos, or by removing rear wheel on fuel filler side, then removing rear wheel well liner (the giant black plastic attached to bodywork with T27 torx screws. Whichever way you access it, the job is relatively simple once you see the white valve part.

[jimbof]

I don't think Superb Mk 2 has the option to remove the vent device - at least newer VW's don't.  Can you see a vent lever in the filler neck when you refuel?

[dieselV6]

Superb Mk2 still has the old style fuel tank, it's Mk3 Octy that has been neutered so far (smaller 50l tank + no ventectomy, for 22% less fuel than vented Mk2 Octy diesel). Rapid and Roomster can still be successfully ventectomized as well. 

[Kazimir80]

try that manual, but theres no vent to hack MY2012 Superb :/

[dieselV6]

Vent valve is clearly shown as a separate item in ETKA for the Mk2 Superb, although marked as "not replacement part", while for Mk1 a replacement is still listed. If they removed it for Mk2 as well, sorry, but seems we Mk1 Superb users have the largest fuel capacity Skodas  :p  you could perhaps double check under wheel well liner whenever the car is up (it's visible when looking from underneath behind the liner in the direction of the filler neck).

Edited 30 November, 2014 by dieselV6