18 replies to this topic

[Johanmini]

hi there,

The fuel tank of my busa mini is quite small. There is this little nipple on top of it, from wich the previous owner told me not to fill the tank all the way because fuel would leak through this little pipe...I asked why not shut it, but he told me the tank had to be able to breath in order not to get a vacuum in there.
Because of the size of my tank and mostly the thirst of my engine it really bugs me I can't fill her all the way up to the top...

Is it really necesarry to have this pipe breathing, or can I shut it, if not, can I put a tube on it all the way up to the bonnet, where the filler is and let it breath like that ánd be able to fill her up all the way? i would say this 30 cm of tubing won't make that much of a difference.

in this picture you see what I mean, with the little breather-pipe:
 IMG_0063.JPG   582.37K   26 downloads

[edsmini]

http://www.ebay.co.u...=item4cfdacdee5

something like this would work but my mini had a piece of pipe fitted to the tank breather and it and was coiled up. (maybe 500mm long) and make sure the end of the pipe is higher than the top of the tank. or fit one of the valves with a length of pipe on the end of it. either way its pretty dangerous driving it the way it is, the vapour from petrol is pretty explosive. plus you have to remember that should the worst happen and you roll the car, it wouldnt take long for the tank to empty.
hope that was the information you needed.

Ed

[R1minimagic]

Agree with the comments, you can get a breather from a scrap yard off pretty much any car fuel tank or even off a bike...

[Johanmini]

http://www.ebay.co.u...=item4cfdacdee5

something like this would work but my mini had a piece of pipe fitted to the tank breather and it and was coiled up. (maybe 500mm long) and make sure the end of the pipe is higher than the top of the tank. or fit one of the valves with a length of pipe on the end of it. either way its pretty dangerous driving it the way it is, the vapour from petrol is pretty explosive. plus you have to remember that should the worst happen and you roll the car, it wouldnt take long for the tank to empty.
hope that was the information you needed.

Ed

Thanks guys, I was pretty certain it could not be normal to drive with the risk of losing fuel, thank god I asked in time.

Is this the same type of product?
http://www.ebay.co.u...cd#ht_525wt_952

Do I just put it on top of it? And what's the purpose of it, when it stops fuel from going out there will still be vacuum when it gets up there, or is this why it should be higher than the max fuel level? Sounds logical as I say it out loud :)

[R1minimagic]

You need a valve so that air can go into the tank to replace fuel as the level of fuel goes down, otherwise a partial vacuum will be present in the tank hindering fuel flow to the pump. This will increase the more the fuel level drops.

Also, as the tank heats and cools you need to let any pressure out but this shouldnt happen that often.

[edsmini]

its like a small diaphram inside of where the valve will be in the closed position, but when the fuel pump starts sucking the fuel out the tank the breather will allow air into the tank without fuel getting out. i would fit the breather like the one i showed you in the link directly on top of the tank then have a length of pipe on the other side of the breather valve with it coiled up which will be a double precaution .

Ed

[Johanmini]

its like a small diaphram inside of where the valve will be in the closed position, but when the fuel pump starts sucking the fuel out the tank the breather will allow air into the tank without fuel getting out. i would fit the breather like the one i showed you in the link directly on top of the tank then have a length of pipe on the other side of the breather valve with it coiled up which will be a double precaution .

Ed

I can do so, but my thought was that it would be best to have the breather as high as possible in order to avoid vacuum in the filltube, as you can see on my photo this part is way higher as where the breather would come and I just want to be able to fill her untill it stops.
What does "coiled up" mean, is this turning it around a couple of times like a spiral and have the end turn upwards?

[edsmini]

yeh it maybe be better in your case to have the end of the pipe higher than the filler neck. the fuel level should never be higher than the breather valve. Coiled up,--- as if you were to wrap the pipe around a beer can or similar. then have the end turned up or down. i had the pipe with no breather valve fitted to my mini and all was fine but my mini never had the filler neck up near the bonnet.

the other option is to have the breather pipe fitted to the top of the tank, then run the pipe up the side of the filer tube then put the breather valve up beside the filler neck.

Ed

[R1minimagic]

It shouldnt really matter if the fuel level is higher than the valve, as it is a 1 way valve and there will always be air in the tube connected to the valve. However, if you dont feel confident about it, just install it on a longer tube, you will be able to see the fuel in the narrow pipe anyway if it is clear pipe!

[Johanmini]

yeh it maybe be better in your case to have the end of the pipe higher than the filler neck. the fuel level should never be higher than the breather valve. Coiled up,--- as if you were to wrap the pipe around a beer can or similar. then have the end turned up or down. i had the pipe with no breather valve fitted to my mini and all was fine but my mini never had the filler neck up near the bonnet.

the other option is to have the breather pipe fitted to the top of the tank, then run the pipe up the side of the filer tube then put the breather valve up beside the filler neck.

Ed

It shouldnt really matter if the fuel level is higher than the valve, as it is a 1 way valve and there will always be air in the tube connected to the valve. However, if you dont feel confident about it, just install it on a longer tube, you will be able to see the fuel in the narrow pipe anyway if it is clear pipe!

Thanks guys,

I'm gonna do as follows like Ed said, put a tube/hose on the thing wrap it against the filler and attach a breather on top of it. Actually it's all pretty logical, just never crossed my mind until it bothered me that I'm not able to fill her up all the way....with the thirst of my engine that's pretty damn uncomfortable!

[cptkirk]

It shouldnt really matter if the fuel level is higher than the valve, as it is a 1 way valve and there will always be air in the tube connected to the valve.

You are correct, It doesnt matter, I have my 1way valve lower than the fill point and I can fill mine to the brim and it doesnt leak.

[edsmini]

Busa engine? oh yes they like a drink of petrol, if i still had my mini one of the mods i would have done was a bigger tank, or as my dad said stop kicking the sh't out of it all the time "yeh rite dad" on a motorway run siting at 70mph all the time i was getting 29mpg so who only knows what you get when you are giving it death. ive seen one of the american companies doing a longer 6th gear for the busas. might be a good mod to get the revs down or fit an old overdrive box from an MG !!!
Ed

[Johanmini]

Busa engine? oh yes they like a drink of petrol, if i still had my mini one of the mods i would have done was a bigger tank, or as my dad said stop kicking the sh't out of it all the time "yeh rite dad" on a motorway run siting at 70mph all the time i was getting 29mpg so who only knows what you get when you are giving it death. ive seen one of the american companies doing a longer 6th gear for the busas. might be a good mod to get the revs down or fit an old overdrive box from an MG !!!
Ed

hmm, My busa turbo isn't measurable in MPG's any more....I count minutes per tanks MPT:) , it's about 20-30MPT! Maybe if I am able to use the complete tank I can manage 3/4 of an hour! LOL.

[R1minimagic]

Just install massive diameter fuel lines like they did on the old F1 cars!!!

[edsmini]

i think this is what you need !!!

i

Ed

Edited by edsmini, 15 March 2012 - 01:57 PM.