Vented Fuel Tank
 

I've nearly got my tank finished now and was wondering how people have vented theirs to comply with the IVA regs? I know some filler caps say they're vented like http://www.cbsonline.co.uk/product/8...ted***_ AEROV but I was wondering if there where other options to vent the tank? Also is there some sort of regulation to have an unleaded insert in the filler neck like http://www.cbsonline.co.uk/product/C..._Insert_LWFCIN as the product description seems to indicate?

i plan on using a non return valve so it vents the tank to atmosphere but in the event of it going belly up it will seal stopping a fuel spillage :D

http://www.ebay.co.uk/itm/Fuel-Tank-...item336841c136

You should really get a proper roll over valve - something like this -

http://www.merlinmotorsport.co.uk/p3...duct_info.html

These should allow air in due to fuel usage, air out due to expansion and will shut off in the event you roll the car.

that cbs one isn't vented i have one and it didn't vent at all. ended up drilling a little hidden 0.5mm hole in it to release the pressure from the tank.

Ah cool, so does both of those options you guys (david & rob) mentioned just get connected onto the fuel line between the tank and the pump/filter?

So I got one of these http://www.ebay.co.uk/itm/Fuel-Tank-...item336841c136 inbetween the tank and the pump. This may seem a bit thick but how does this vent the pressure in the tank as it will always have fuel in it? Does it just let some of the fuel leak out to relieve the pressure?

It should be mounted to an outlet on the top of the tank then to atmosphere, so air can get in but fuel cant get out

Ideally it should be two way to let pressure out when its hot too, but seal in the event of a roll (as in davidmurrays link)

Ok thanks mark.

Out of interest do you actually need on of these valves? I can't recall seeing in the iva manual anything about one way valves.

I know the tank needs to be vented. If you took a hose from the top of the tank to below the bottom of the tank, if the car was upside down the bottom of the hose becomes the highest point and the tank won't empty anyway.

I know it doesn't work if the car ends up on it's side, but if you manage to end up upside down, or on your side you'll be in a pretty bad state / dead I would imagine.

Lol encouraging dave! Personally I'm not worried about the shutoff side of this, like you said there's not requirement from an iva standpoint. I was just after a cheap and simple way to vent it.