Auxiliary Fuel Tanks - Pro/Cons?

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@LivEviL Did you get small/large evap leak codes when your fuel pump broke? I have a gx460 with aux tank and the fuel pump was installed above the suspension geometry and got smashed like your situation. It was sitting for a few days and the ecu ran an evap test overnight I'm assuming, resulting in it detecting an evap leak from the pump. Wondering if you experienced the same
 
Where/how do you carry the spare? And do you just ignore the TPMS light/warning on the dash when you're not carrying it?

My biggest concern is having to resort to a swingout tire carrier for the spare. That thing would just plain suck for me. I have the swingout for my bumper sitting in the basement, I've never installed it. I asked this before but didn't get any responses: does the swingout hit the trailer when you're towing? Am considering adding a teardrop trailer, but there's no way to test it out.

For day to day around town or on short trips less than 3 hours or so, I don't carry a spare. For the TPMS, I just made a small PVC tube and put a receiver in it, pressured it up to 30psi and leave it in my "trunk bag." Works great. There's a great thread that I used as instructions for buying the Autel TPMS clone device that I found on the forum. The actual TPMS universal sensor is about $35.

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@LivEviL Did you get small/large evap leak codes when your fuel pump broke? I have a gx460 with aux tank and the fuel pump was installed above the suspension geometry and got smashed like your situation. It was sitting for a few days and the ecu ran an evap test overnight I'm assuming, resulting in it detecting an evap leak from the pump. Wondering if you experienced the same
No. I could smell the gas and crawled underneath to see it.
 
More typically I will see ~7 to 7.5MPG adjusted, driving ~72-74 most of the way. So 150 miles on a tank in that case

Good stats there. That sure is a bundle of gas money but it's smiles for miles and that was an epic trip! I hope to join you all at LCDC one year.

My towing MPG is elastic depending on speed and environmental. I find myself driving faster and faster these days with the trailer, CAs towing 55mph speed limit be damned. Especially with 35s making the speedometer read 5mph low. Corrected, I'm driving around 68-75mph. I've also seen tanks in the 7MPG range but that would be the low end exception for my setup, when in winds. Looking at my last trip which was a lot of grades in the sierras and 100* degree+, I saw a corrected MPG between 8-11MPG range. I was surprised at the higher 11MPGs and that was done mostly at 4k+ elevation. Seems like air density impacts to engine output and aero drag helped that tank.
 
Good stats there. That sure is a bundle of gas money but it's smiles for miles and that was an epic trip! I hope to join you all at LCDC one year.

My towing MPG is elastic depending on speed and environmental. I find myself driving faster and faster these days with the trailer, CAs towing 55mph speed limit be damned. Especially with 35s making the speedometer read 5mph low. Corrected, I'm driving around 68-75mph. I've also seen tanks in the 7MPG range but that would be the low end exception for my setup, when in winds. Looking at my last trip which was a lot of grades in the sierras and 100* degree+, I saw a corrected MPG between 8-11MPG range. I was surprised at the higher 11MPGs and that was done mostly at 4k+ elevation. Seems like air density impacts to engine output and aero drag helped that tank.
I'm sure my front bumper and all the crap on my roof rack have a surprisingly large impact on my MPG

Yeah I have to agree on that 55mph CA towing speed. When we were there a few summers ago I felt it was outright dangerous, particularly on that stretch coming in from Vegas. Try and merge at 55 when the car speed limit is 65 and everyone is doing 70-75 anyway.
 
I would caution extending the hitch shank to create clearance especially with larger trailers. This could have significant impacts to sway as it modifies the wheelbase to rear overhang ratio, better known more simply as wheelbase and its influence on stability. On the travel trailer forums, owners of HD trucks sometimes use these extended shanks to make clearance against the tall tailgates and tongue jack, only to find that even HD truck will sway at lower speeds. The other dynamic is that it gives leverage to tongue weight. This will shift a greater percentage of weight off the front axle onto the rear, as well as increase porpoising. With rear bumper, swingout, and spare(s), it's likely to push rear axle loads into 5k+ lbs. (Rear GAWR is 4.3k lbs)

If clearance is really needed, a better strategy may be to lengthen the trailer tongue with an extended coupler. This might seem extreme at first blush, but trailer service departments weld new couplers on all the time and is actually not that expensive. It has side benefits in increasing stability and reducing trailer tongue weights.
 

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