HOrnbrod Posted October 28, 2016 Share Posted October 28, 2016 As far as I know, the purpose of gas tank baffles, i.e. strategically placed plates, were to limit the transfer of fuel weight on turns to improve stability, cut down on fuel slosh, and keep the slosh from beating the crap out of the fuel sender lever/float assembly giving erroneous gauge readings. A tank baffle doesn't limit the capacity, si? What you are saying is that an internal compartment, not a baffle, was added to limit capacity. Correct me if I'm wrong.......... Link to comment Share on other sites More sharing options...
johnj92131 Posted October 28, 2016 Share Posted October 28, 2016 The old Wranglers had a 15 gallon gas tank rating from the factor. The trick was that the gas filler tube was extra long inside the tank. Some owners reported cutting the filler tube inside the tank shorter and filling the tank up to 20 gallons with no other modifications. Just what I have read. Now this trick and the one Go-Jeep uses to get and extra 5 gallons in the Cherokee XJ tank actually removes gasoline expansion volume area from the tank and replace it with liquid gasoline storage. Result, in hot days and when fuel is heat soaked it expands and flows out of the tank - IF the tank is full of gas at the time. If you are down 5 gallons, then you have the stock expansion area/volume in you fuel tank and gas does not over flow the tank. Don is quite correct in what the baffles do inside the tank. They simply control the fuel sloshing in the tank and have nothing to do with how much fuel goes in the tank. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 28, 2016 Share Posted October 28, 2016 Good explanation John. Gojeep's cutting down the filler tube to increase capacity makes perfect sense now. :cheers: Link to comment Share on other sites More sharing options...
mikekaz1 Posted October 28, 2016 Share Posted October 28, 2016 fwiw, gas doesn't expand that much... you would have to be REALLY topped off for it to expand out on even the most extreme days. .069% per degree if you want to get technical. Link to comment Share on other sites More sharing options...
gogmorgo Posted October 28, 2016 Share Posted October 28, 2016 I was trying to work out some way I could fill the tank, let it sit at -40, top it up again, and then drive somewhere where it hit 80 degrees or more, but then I remembered that the level in my tank has this annoying habit of dropping when I drive that far. Link to comment Share on other sites More sharing options...
Megadan Posted October 28, 2016 Share Posted October 28, 2016 Well, Coming next spring I plan on swapping out to the 23 gallon unit, so when I do this I will try to document it. I had a feeling the sending unit was the same, but sometimes things get tweaked from the factory for reasons not thought of. Thanks for the feedback. Link to comment Share on other sites More sharing options...
mikekaz1 Posted October 30, 2016 Share Posted October 30, 2016 I was trying to work out some way I could fill the tank, let it sit at -40, top it up again, and then drive somewhere where it hit 80 degrees or more, but then I remembered that the level in my tank has this annoying habit of dropping when I drive that far. haha Link to comment Share on other sites More sharing options...
mikekaz1 Posted October 30, 2016 Share Posted October 30, 2016 I was trying to work out some way I could fill the tank, let it sit at -40, top it up again, and then drive somewhere where it hit 80 degrees or more, but then I remembered that the level in my tank has this annoying habit of dropping when I drive that far. haha Link to comment Share on other sites More sharing options...
smokey Posted March 31, 2019 Share Posted March 31, 2019 I love posting to old threads. So I just bought a 1988 Long bed Comanche from the original owner and drove it 1500 miles home. Have to say why in the world would they make a 16 gallon tank? When I got home I pulled the tank and stamped on the side is 16 gallons. It has three straps and the measurements are 33.5 inches by 12.8 inches by 12.2 inches. The math comes out to 2.978 cubic feet which is 22.3 gallons of space. So I filled it with water and low and behold it held 23.8 gallons of water. It is the filler next that extends into the middle of the tank almost half way that limits the space. Also on fillups it causes the auto stop on the pump to blow gas out over the side. Has anyone cut the filler neck? And the most important question of the day what were they thinking making a tank the exact same size as the 23.5 tank but make it only hold 16 gallons? If you want less weight just don't fill it up. Sorry for the rant was thinking about it for 1500 miles. Link to comment Share on other sites More sharing options...
gogmorgo Posted March 31, 2019 Share Posted March 31, 2019 You can get someone to pay more for the same tank if you tell them it's bigger. Link to comment Share on other sites More sharing options...
Pete M Posted March 31, 2019 Share Posted March 31, 2019 trimming the hose is super common with wranglers. they all came with the same tank but 2 different "full tank amounts". Link to comment Share on other sites More sharing options...
smokey Posted April 10, 2019 Share Posted April 10, 2019 Ok, update on my 16 gal fuel tank. So after all the testing, I decided to cut a hole in a perfectly good fuel tank. Then I cut the filler neck and overflow inside the tank and resealed the hole I cut. I finally got to the gas station and filled up with 23.6 gallons and the auto stop on the fuel pump didn't puke fuel on the side of the truck. If you look at the over flow tube it was bent at a 90 degree angle and was halfway into the tank. So it looks like the only difference between the 16 and 23 gallon tanks are the filler and overflow in the tank. Link to comment Share on other sites More sharing options...
Pete M Posted April 11, 2019 Share Posted April 11, 2019 are you uploading from a laptop or phone? Link to comment Share on other sites More sharing options...
thousender Posted July 13, 2021 Share Posted July 13, 2021 Can I use a 23.5 gallon tank on my 87 2.5l 6ft bed. I currently have 2 straps and it seems that I'll have to stick with the 18 gallon but before I buy a new tank, I'm curous to know if the 23.5 gallon will fit with or without SOME fabricating. Link to comment Share on other sites More sharing options...
Pete M Posted July 13, 2021 Share Posted July 13, 2021 if I remember right, it invades the axle's space a bit. Link to comment Share on other sites More sharing options...
Eagle Posted July 14, 2021 Share Posted July 14, 2021 10 hours ago, thousender said: Can I use a 23.5 gallon tank on my 87 2.5l 6ft bed. I currently have 2 straps and it seems that I'll have to stick with the 18 gallon but before I buy a new tank, I'm curous to know if the 23.5 gallon will fit with or without SOME fabricating. It won't really fit even with fabricating -- unless you cut the 23-gallon tank down to the size of the 18-gallon tank. Link to comment Share on other sites More sharing options...
thousender Posted July 16, 2021 Share Posted July 16, 2021 On 7/13/2021 at 7:45 PM, Eagle said: It won't really fit even with fabricating -- unless you cut the 23-gallon tank down to the size of the 18-gallon tank. That's what I thought. Thanks for the reply, now I don't have to worry about spending 200 bucks on the wrong tank! Link to comment Share on other sites More sharing options...
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