
Fuel tank breather
#1
_Bomber Watson_
Posted 04 January 2009 - 12:08 PM
Has anyone ever thought of increasing the size of the standard fuel tank breather on a LC/LJ???
I am going to be making a custom tank up at some stage and just looking at teh size of the puny little 3/16" line i thought that perhaps this may cause starvation at high revs/high fuel demand.
Seeing though I wont be thrashing the car except for on the quarter mile it probably wont be a drama, but i thought that perhaps a 5/16" line bent into a similar shape to the standard one would be better???
I dont want to vent into the boot area.
I wont be using the standard fuel tank pickup anymore, that will simply be in there for a fuel sender, so i was thinking that perhaps i might be able to cut the pipe off just as it goes into the tank (leaving one side of it to hold the sender if you follow me) and run 5/16" bundy up the back of the rear firewall as per factory.....
Just ideas.
Any thoughts? Has anyone ever had any dramas with this before?
Cheers.
#2
_scottya!_
Posted 04 January 2009 - 01:04 PM
being sucked out to avoid any vacumm in the tank. cheers scott.
#3
_Bomber Watson_
Posted 04 January 2009 - 02:38 PM
Now fair enough the motor probably wont be drawing as much as the fuel lines heading to it can deliver, and with a standard motor the standard sized breather would be perfectly ample, but in a high performance application i think that a larger one could be beneficial.
Thats why i started this thread to discuss this..
Cheers for your input.
#4
Posted 04 January 2009 - 02:40 PM
#5
_Drag lc_
Posted 04 January 2009 - 03:23 PM
judging buy the amount of fuel that used to piss out of it.
Thanks hayden
#6
_PRO-192_
Posted 04 January 2009 - 03:48 PM
cheers
micko
#7
_Bomber Watson_
Posted 04 January 2009 - 06:44 PM
So basically not really needed but i can do it if it makes me feel spethial (said with lots of spit). Also i never thought of a one way valve, i like that idea and will incorporate one.
Cheers.
#8
_PRO-192_
Posted 04 January 2009 - 09:08 PM
micko
#9
_sshatch355_
Posted 04 January 2009 - 10:39 PM
his engine was making huge power so not sure how relavent it would be but guess every lil bit helps
#10
_PRO-192_
Posted 05 January 2009 - 12:23 AM
a few years ago when we actualy had a drag strip that was open (yes im bitter n hate bob jane) there was i think it was a camaro with a full house pat mussi bbc that wasnt running the numbers it should of and after a lot of hair pulling it was found the fix was as simple as removing the petrol cap as the breather was not big enough to cope with the amount of fuel being used. as soon as it was removed the numbers dropped...
his engine was making huge power so not sure how relavent it would be but guess every lil bit helps
mate do you realise how much volume even a 5/16 hose can move?? i mean look at it like this, you are talking about an engine if it has 1 carby say a 1050 dominator/bg demon/whatever for arguements sake and it runs 9.50's over the quarter... how much can it use during this time... lets say 1 litre which is way over the top... now get the same 5/16 hose and siphon some fuel for 10 seconds and see how much you get... i mean in theory if you hav a 5/16 breather you would need to have a larger than 5/16 size hose amount of fuel going into the engine for the effect to be reversed... its just physics... and common sense...
and did they seriously let this dude race without a petrol cap?? if so no wonder the place got shut down... or did someone get killed??
micko
#11
_sshatch355_
Posted 05 January 2009 - 02:00 AM
it made sence to me at the time and i hadnt ever thought about it till i saw the post...
cheers pete

#12
_PRO-192_
Posted 06 January 2009 - 05:50 PM
micko
#13
_Bomber Watson_
Posted 06 January 2009 - 06:01 PM
I was thinking about changing it to 5/16".
#14
_PRO-192_
Posted 06 January 2009 - 06:06 PM
cheers
micko
#15
_Bomber Watson_
Posted 06 January 2009 - 07:33 PM
But we are talking about Toranas here not Camaro's, it gets confusing once we start mixing these things up.
Where can i get one of those one way valves from?
Cheers.
#16
_PRO-192_
Posted 06 January 2009 - 07:48 PM
i hear ya loud and clear bomber lol
micko
#17
_scottya!_
Posted 06 January 2009 - 08:39 PM
#18
_lx-304_
Posted 06 January 2009 - 08:48 PM
#19
_sshatch355_
Posted 06 January 2009 - 09:08 PM
yes correct... all of us were, except sshatch
i hear ya loud and clear bomber lol
micko
was just relating a something i thought may be relevent to the issue


#20
_PRO-192_
Posted 06 January 2009 - 09:24 PM
cheers
micko
#21
_PRO-192_
Posted 06 January 2009 - 09:25 PM
micko
#22
_sshatch355_
Posted 06 January 2009 - 09:40 PM

ive got no problem being corrected when wrong, its one of the best ways to learn.....
#23
_Bomber Watson_
Posted 06 January 2009 - 10:10 PM
At the end of the day if X amount leaves the tank in Y time then X amount must get back into the tank in Y time.
Now dont try to tell me no motor would drain more than a 3/16" line can provide back, even if air is more viscous than fuel.
Cheers.
Edited by Bomber Watson, 06 January 2009 - 10:11 PM.
#24
_PRO-192_
Posted 06 January 2009 - 10:29 PM
micko
#25
_82911_
Posted 06 January 2009 - 11:22 PM
Slosh some E85 and marvel at the lack of aeration.....
Bomber for reference. I have one x -6 vent in my system which is a replica of the system that is used in 90% of the current supercars. No problems at all either on track or dyno 496@the wheels.
Cheers Greg...
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