Now the question is what type are you using?

 

no ofence to the person doing that mod. but thers a reason thers air left inside... all tanks have extra space....

 

i found the owner's manual has the tank sizes on the last page. my build sheet has a 20 gallon tank listed for the 87 i have but when i drive it to the middle of the red and filled it up, only 14 or 16 gallons would go it

 

yeah the reason is that jeep was to cheap to make two different tanks. the tanks are the same size. Go jeeps write up that i posted is how to make the smaller one (not actually smaller) act like the big one

 

i followed the link to read it but i am a fan of having that expansion room since most of the year the temps are well over the 90s and alot of plus 100 days. made me think of when you have a gas can in the shed, how it gets all puffed up during the day when its hot and hten goes back to normal when it cools at night. thats to much stress on your rubber lines for me. plus, if you crank that cap on tight and its gets really hot, what happens if you have a slightly less then perfect seam on your tank? pow, your out a tank.

 

so the breather tube conected to the charcoal box doesnt do enough for yeah? the fact that the tanks are engineered to handle both capacities doesnt sound good for ya? maybe you should play it safe and only put in 3 gal. at a time

 

i just treat it like my 20 gal. tank has a 3 gallon reserve. the light comes on when i use about 15 gal. or so, and i fill up when it hits about 17 gal (when my gauge is on the empty line). never ran out of gas yet because i don't want to be freaking out when i am at the point i have used 19 gal. and have 25 miles before the next gas stop on the freeway.

only modification i'd want to do is replace the metal tank with a plastic one.

 

The gauge on my 92 reads 3/4+ when topped off.

There's is an easy mod in the tech section to increase capacity to 25 gals.