Down the road I will be install a new rear bumper with a tire swing out relocating the spare from under the vehicle. Does anyone know if anyone making an auxiliary fuel tank to fill the space where the spare tire was? Be great to gain an extra 10-20 gallons instead of carrier it on the bumper.

If you search around there are several threads on this already. The general consensus is no. Here is just one of the threads...

Thanks

5th Gen 4Runner Gets A Few CBI Mods | CBI Offroad Fab

I think I saw the price somewhere was between 5-6K with bumper, fuel tank, and skids. If I ever want to get divorced this is the set up I plan to purchase.

That was a one off, I think generally most companies aren't doing production fuel cell's due to a liability issue.

It was the only build I have seen that was integrated in a way I think the OP wanted. I agree Ive never seen any production versions, but being that he was looking for a new bumper and fuel cell I thought it might be of interest.

I understand that. I asked CBI about something like that and they generally dodged the question. I think it was one of those, "sure we can make one, but sign this waiver." Sort of things. The minute it's a production item then things get weird.

The problem is with all the fuel tank safety requirements (DOT and EPA) in the USA, along with associated liability. Automatic gravity/siphon feeds are illegal, etc.

I've seen where OEM dual-tank filler nozzles are available in other countries for some Land Cruisers, but nothing for the 4Runner. They have a Y-connection with a flapper to switch between tanks. http://www.sleeoffroad.com/technical/tz_fuel.htm

How do custom motorcycle ships get around this? Are this tanks regulated differently? Just curious...when I had my Tundra that was actually high on my list to get installed, but there was a reputable company who had a DOT approved tank that could be ordered.

I saw a few for the Tacoma, not sure if they would fit. Most were custom builds, but I remember one from Australia that people were shipped to the US. If I remember correctly, something went sideways and several people got tanks stuck at the docks.

It can be done there are several for the FJ.Man-a fre comes to mind should be adaptable to the 4R with some work. Not DOT but hey.
Edit: looks like the man was brought up in the linked thread already and werner runs one....

Thanks all for the information... Now let me see what I can get done... Cheers!

Yes, completely different rules for motocycles vs. passenger vehicles. Motorcycles also don't have restraints, airbags, etc.

It can be done on the 4runner, it's just expensive and there are liability issues for a commercial operation. Not to mention the problems with smog controls and such... adding an extra tank can do strange things for the leak-test and overflow preventers that can cause your computer to throw error codes. I live in a county where emissions testing is required, so that would kill it for me.

Even with all these problems, if there were enough demand someone would develop a drop-in sub tank or else a replacement for the OEM tank that is larger. But the market just isn't there. People just don't use mid-sized SUV's to haul heavy trailers long distances, which is the typical application for larger tanks.

Personally, on first thought, I'd love a larger capacity. I make a trip a few times a year that is just slightly longer than my 4Runner's range. It's annoying to have to fill up twice each direction (once a few dozen miles after setting out, again mid-trip or on arrival).

On the other hand, there's a reason why passenger jets don't carry a full fuel load on short-hop flights. The extra weight would cause a loss of mileage during daily driving.

Well said. Honestly, we get a lot more range out of our 4runners, even in expedition setups, than the FJC's do with their marginally smaller tank. i don't find range is limiting. We're not in africa trying to cross 900 miles on one tank.

I picked up an 11 gallon auxiliary tank off craigslist for a 4runner. Can't recall who it was manufactured by, but it was a company purchased, I think, by Northwest Metal Products. Fits above the spare tire.

Supposed to be gravity fed with an independent fill neck located in a rear wheel well, but I'm going to extensively modify it with transfer pumps and an independent fuel level indicator.