Fuel tank vent

[BrianN]

I have built a larger fuel tank. What size of vent fitting do ya'll recommend? -6, -8, -10? I may have to build a bigger motor, this thing(full) is freakin heavy!

[DeepBusch69]

How many gallons do you estimate you have now?  I used 3/8" line just because I had some.  5/16" would work I bet.  I did change the vent line routing, it used to leak with a full tank parked on hill.  I ran it up around the roll bar then back down along the bottom and back up to about where it starts.  I didn't really want to test it, but first trip, yea I rolled it.           It did work great though, not a single drop leaked!

[BrianN]

I am guessing close to 9-10. I have been researching vent lines, and what the desert racers do. The subject gets very involved,  concerning safety. It sounds like yours could create a air lock if fuel got into the line while driving.  Am I reading that correctly? I  do read that it should go to the top of the cage, across to one side, then back down to bottom of the frame. Do you have a filter on the end? I know the roll-over valves are definitely something that different people/teams have different opinions on. DSRACE and I have discussed this,  also. I am now spraying my tank with what is supposed to help keep heat out of the tank.

[DeepBusch69]

I have the roll over valve at the tank.  The line then routes just like you described, I did add a filter.  Like you said, it's the way desert racers do it

[BrianN]

I need to add that I am not doubting your method, just want to learn the reasoning and proven methods.

[dsrace]

this is important and mine had a roll over valve but it didn't vent well. i think the fuel got to it and have been looking into a diff idea. on the last trip when i parked on a slant with a full tank, it ran out my vent.  i do think up the cage and over then back down it a good idea but always open to other ideas!

[dsrace]

one issue on mine is the line isn't large enough. i am running 3/8" and it goes to the top of my radiator. that is 2' above the filler neck but while running parked on decent slant it pushed it's way out that pod filter and ran down the tail pipe. luckily it's double wrapped but that could've been very bad! i will be addressing that before the next trip.

https://www.tanksinc.com/index.cfm/page/ptype=results/category_id=160/mode=cat/cat160.htm

i am not sold on the tip over valves as i run e85.

[dsrace]

something like this maybe

[dsrace]

brian you should post up some pics of what you've been up to...... you know in between the T.H.A meetings  turbo holics anonymous  i skipped the last meeting 




   

[BrianN]

Yes,  we missed you last week. Nobody knew how to start the meeting without their leader! But I might say, I am starting to think that THA is having a  reverse affect on me. I am simply learning new tricks and meeting new holics. So, boys and girls, if you are trying to the boost habit, DON'T call dsrace!

I will share some pics later, when I get organized better.

I went with -8 on my vent. I am considering going straight up to the top of my cage, then a "T", going with larger hose to each side, then down to bottom rails. Criticizing welcome here, because I may be missing something.

[dsrace]

last meeting was just new member introductions. i was front row

[fabr]

something like this maybe

That is the only proper way and a vent line doesn't need to be any larger than even an 1/8" *(ya,I used 5/16)unless you are using a dump can to fill the tank like racers do.  Then like 1" or more!

[dsrace]

i run 3/8" now and have considered 1/2". i'll give .25" a try when i adapt that diagram.

[dsrace]

i do need to figure out a larger tanks before the next st a trip.

[fabr]

No need at all for a large vent line. Truth be told ANY size vent will allow plenty of air into the tank to avoid any chance of vacumn. Hell ,  .005" would do!  .   Now,if we were using dry break dump cans to fill our tanks , a very large vent line is required.