Jerry Cans vs. Replacement/Aux Fuel Tanks - Pros/Cons

[CanuckMariner/Nomad]

I always seem to get into this discussion with my son and wonder what you all might think? We could do it here, kinda like a OJ test without the testing, just the discussion and conclusions.

Having 2 rigs [73/77 series]: one [73] with replacement tank + 2 jerry cans [H2O] and one [77] using 2 jerry cans [fuel or H2O], I have done considerable research and discussions on this very topic. When I got my 77, I considered it for a replacement tank, but I found it gets incredibly good fuel economy (8-9 L/100kms - HWY; 9-11 L/100 kms City) in its stock condition with my current mods. I use the jerry cans primarily for water - both drinking and/or showers, as I spend considerable time travelling in deserts. Both are diesel but lets not get into that now. Just know that the pros/cons below are what precipitated my discussions with my son and now your input is requested in case we missed something.

Please stay on topic and no smartalek/rude/disparaging comments; as it seems the norm on most threads these days! Oh, and no hijacking!

Lets keep this a constructive and informative discussion, so we can get a good consensus of the pros and cons of doing/or not doing. No personal discussion of one's mod, if they already did it - this should be on a build thread. Opinions and facts only, please! This discussion is about a hypothetical mod on a hypothetical rig, before one actually does it, to get the pros/cons of both and then take the appropriate course of action.

Neither mod is right or wrong; nor one mod having more or less pros/cons doesn't mean it is more better or worse, both have their applications. My reason for doing this, is to give others out there some food for thought when considering either mod and to add to my consideration for the future.

First of all, lets lay some ground conditions/assumptions/considerations to keep things more better:

• The mod is either 1-3 jerry cans* (few usually carry more - so 20-60 L) with corresponding jerry can holders, spouts, fuel funnel filter or super siphon vs. replacement tank = to stock tank + above jerry cans equivalent or better OR + aux tank = to above jerry cans or better, with pump, gauge, electrical or gravity drain with appropriate plumbing for both conditions assume aux tank with additional filler pipe;
  
  [*]my thought on this is: why would one get a replacement/aux tank mod when it can't hold as much or more than the jerry can option?​
• all discussions are with same vehicle with same options, conditions, tires, gear et al., no matter what you choose (limits discussion of different rigs and additional variables and focuses on the two mods) and no trailer.
  
• all fuel tanks have baffles and everything to maintain safety in either custom or used tanks
  
• all discussions are with same driving conditions (again limits variable discussions)
  
  1. hypermiling (the act of driving using techniques that maximize fuel economy) - coasting, 80-90 kph, et al.,
  2. heavy foot (100+ kph),
  3. 4x4 conditions < 50 kph)
  4. road conditions - highways, gravel roads, off road conditions
• the rigs use the same fuel type - however, diesel does present some benefits and this will be mentioned once^ but NOT discussed here again
  
• there are insurance and safety issues with both mods so these will NOT be discussed or factored in.

* With the jerry can situation, it is assumed that the jerry cans are carried on a bumper (custom or not) which also carries the spare tire; OR they are carried on a roof rack; OR carried inside the rig (some do this). Also, some states (CA, others?) have safety requirements (CARB, non-spill spout, child proof, etc.) on jerry cans and these also will NOT be discussed here

^ Diesel fuel has its own situation as it is sold (marked or red dye diesel) in some regions without local road taxes for "off-road" use. This can be as much as 20% less than regular prices (despite quality of fuel - #1, #2, blended, etc.). Gasoline in some cases is also sold in a similar fashion but for farm or non public road use only and generally in bulk at special outlets. Having larger fuel tank capacity obviously makes this more economical under this circumstance. The legality of either will NOT be discussed here.

My thoughts/opinions:

Jerry Cans - what ever number you carry

Pros

• least expensive mod
• easiest to install mod/to do
• cool factor - looks
• less weight (generally)
• easier to lighten load when stuck
• more flexibility, non permanent,
• access to fuel for starting fire in wet/inclement conditions, cleaning parts, etc.
• potential weight distribution in front of rear axle rather than behind
• jerry cans can hold red or marked fuels and qualify for tax refund on fuel costs
• shuttle fuel back and forth to ones rig - out of fuel, share fuel with others, etc.
  

Cons

• least convenient (PITA)/cumbersome - fill up and drain to fuel tank by whatever method, weather conditions can make this more difficult/uncomfortable
• fuel handling is dirtier, cumbersome, inefficient
• storage on rig and at home (or permanently left on rig)
• extra equipment required - spout, super siphon
• storage inside presents potential hazards, stored on RR is cumbersome to say the least, stored on bumper requires additional fuel handling
• potential vandalism - drained, stolen, damaged, addition of foreign material
• expansion of cans from heat making them difficult to open

Replacement/Aux Fuel Tank Mod

Pros

• increased range
• better fuel economy due to continuous driving condition rather than more frequent stops
• less stop/go driving - easier on rig, maintenance, etc.
• gives owner more choice of when/where to get fuel
• benefit of getting more fuel at a better price
• less and cleaner fuel handling
• overall convenience
• less vandalism opportunities
• stealth - look
• lower COG than with jerry cans, better stability
• may be fitted with a parallel fuel system pump, lines, etc., and switched from the dash. This is a reliability issue.
• no environmental considerations due to spillage/leaks from filling (jerry cans)
• potentially less danger of accidents causing fire or explosion (depends on who or how it is built)
• aux tank can hold red or marked fuels as it is separated from main tank and costs can be used for refund
• fuel variability (reg in one tank vs Bio in aux) same for reg and Bio diesel

Cons

• finding a used or 3rd party tank that fits your situation can be difficult
• finding a shop to make a custom tank may be difficult
• having a spot to put the increased replacement tank and/or aux tank maybe difficult on some rigs
• initial cost is higher
• installation is more time consuming, difficult, complicated and problematic
• increased weight
• potentially less driving breaks, pit stops, relax/stretch, etc.
• decrease in fuel economy due to increased weight
• increase cost of fillings i.e. each full tank costs more
• increased amount of fuel hence some increase safety risk - explosion, accident, leakage, fire, etc.
• potential border crossing issues - maybe interpreted as contraband carrying device

I will add your pros/cons and thoughts to this initial listing/post as I hear from you, so this can be the conclusion as well.

Any suggestions on how to present this in a more better way, please let me know.

Edit: just thought perhaps someone can do a similar poll and thread on water jerry cans vs. water bladders and water tanks, permanent or removable.

 

[Mike S]

I have a Aussie Long Ranger aux tank in my 80. There are many more 'pro's' than you listed...

> Weight is down low which helps reduce COG issues

> May be fitted with a parallel fuel system )pump, lines, etc., and switched from the dash. This is a reliability issue.

> No fooling with cans that can leak, drop raw fuel into the environment, or cause problems for passengers.

> Less danger of accidents causing fire or explosion.

I LIKE HAVING 69 GALLONS OF FUEL ON BOARD WHEN I HEAD TO THE BACKCOUNTRY. That is equivalent to 9 jerry cans.

 

[048642]

It's nice to be able to unload the fuel cans to lighten the load when you get stuck.

 

[WhereTheHellIsJames?]

It's nice to be able to unload the fuel cans to lighten the load when you get stuck.

Was thinking the same thing... 69 gals of gasoline is a lot of weight (+/- 430lbs!). However, as Mike pointed out, it would have a positive effect on the COG if it was down low like his tank, so that much weight could be a good thing too.

pros & cons...

 

[IggyB]

I have a few Scepter cans.

When I tow the M101 (1/4 ton), my mileage gets worse. So I put 3-4 cans in it. Sometime I fill them up at the last gas station available, sometime at home.

Without the trailer I occasionally fill 2 cans and put them in the bed.

Clean, easy to empty, lots of carrying options, simple, non-permanent, can be used to start fire on soggy day and so on.

 

[Metcalf]

One of the best arguments for Jerry cans that I have heard.....

Give the same amount of fuel weight, if you become stuck you cannot easily unload fuel from an auxiliary tank to make the vehicle lighter. With Jerry cans you can easily load and unload the vehicle to reduce weight if needed.

Some more points.....

-In general most auxiliary fuel systems ( cans or tanks ) generally put the weight too far rearward, generally behind the rear axle. It is very rare that you see anyone pack additional fuel ahead of the rear axle. Some vehicles don't lend themselves to this....but you just have to get a little more creative.

-I do like that most auxiliary fuel tanks keep the weight down low. For dynamic vehicle performance having the weight lower is more important than having the weight forward. For off road performance ( hill climbs, sand, etc ) will be better with weight forward. A vehicle that is heavy on the rear axle doesn't perform as well as one with 50R/50F. A little front heavy is even better generally IMOO.

 

[TangoBlue]

In addition to other observations...

Assumption: a reserve tank and weight of the fuel will cause additional stress/fatigue on the frame or supporting crossmembers, requiring reinforcement, therefore additional weight.

Assumption: location of the auxiliary tank and more aggresive offroad conditions will require additional protection requiring additional attachment points and armor, therefore increased weight.

Assumption: separate fueling point required for an additional tank requiring bed or body modification.

Assumption: modification of stock fueling point to accept dual tank fueling capability might not be possible due to space restrictions or be cost prohibitive.

Assumption: modification to fuel system may cause errors in ECU monitoring resulting in operating errors.

Assumption: modification in fuel system might cause vehicle emission test failure in some jurisdictions emission testing or may be in violation of some state vehicle codes.

That stated I will demonstrate uncharacteristic restraint and will not discuss my plans to make this modification to my vehicle.

STEP BACK FROM THE KEYBOARD.

 

[007]

A pro for the replaceable tank is that it can be made stronger than the factory tank or positioned better.

A pro for the auxiliary tank is that you have a spare and can also run red dye diesel or off-road gas when off road, and taxed fuel on road with a switch of the lever. (in the states you can also record the amount of fuel used during off road for a tax refund)

Another aux tank pro is that you could run bio-diesel in one tank but Diesel in the other when temps are an issue.

A pro with having ONE jerry can is that you can easily shuttle fuel back to your rig, to others, or wherever.

 

[journey]

A con for aux. tank is increased suspicion at border crossings. It might seem like a 20 gallon drug carrier. A Jerry Can would be easier to inspect.

 

[CanuckMariner/Nomad]

In addition to other observations...

Assumption: a reserve tank and weight of the fuel will cause additional stress/fatigue on the frame or supporting crossmembers, requiring reinforcement, therefore additional weight.

Assumption: location of the auxiliary tank and more aggresive offroad conditions will require additional protection requiring additional attachment points and armor, therefore increased weight.

Assumption: separate fueling point required for an additional tank requiring bed or body modification.

Assumption: modification of stock fueling point to accept dual tank fueling capability might not be possible due to space restrictions or be cost prohibitive.

Assumption: modification to fuel system may cause errors in ECU monitoring resulting in operating errors.

Assumption: modification in fuel system might cause vehicle emission test failure in some jurisdictions emission testing or may be in violation of some state vehicle codes.

That stated I will demonstrate uncharacteristic restraint and will not discuss my plans to make this modification to my vehicle.

STEP BACK FROM THE KEYBOARD.

All valid points, but I think I caught that with the more complex installation, problematic, etc. as well as difficulty in finding the right tank, builder and location.

A pro for the replaceable tank is that it can be made stronger than the factory tank or positioned better.

Clint I agree with most of your points, however building a strong one or better positioned is subjective, as it goes to the skills of the build and I believe auto manufacturers/engineers have spent considerable resources (R&D) to get this right from the onset. By building a replacement/aux tanks, who knows what we are doing to the dynamics of the vehicle.

 

[CanuckMariner/Nomad]

You have all come up with some very good :iagree: points that I missed (most have been added to summary post#1) in my discussion with my son on this topic. Thank you thus far.

Slightly Off Topic (sorry ):

Another point to raise in doing a discussion like this, is that everyone has input, it is constructive, all data is in one thread, a poll summarizes user methods, summarized in the first post with explanation and comments to follow, etc.

Would this not be a more ideal/informative format to follow for all equipment mods and related discussions: dual batteries mods, batteries in general, isolators, dual battery systems; water carrying, storage, systems, camp chairs, tents, stoves, roof racks, front bumpers, winches, winch lines, tires, rims, breathers, trailers, etc.

I think you may get the point that any topic would be better organized than the current methods used on various threads and repeated yet again somewhere else and members keep asking over and over and over again.

I encourage others to begin other mods, gear reviews, etc. in a similar or more better fashion than this thread.

 

[SunFlower]

My 2008 Fj Cruiser has a small gas tank so I looked into an aux fuel tank. However,it was expensive and according to reviews I read, they seem to have problems tripping codes.
Instead, I modified my OEM roof rack to hold 3 (5) gallon plastic jugs. It works perfectly and only cost about $95 bucks total.

 

[CanuckMariner/Nomad]

My 2008 Fj Cruiser has a small gas tank so I looked into an aux fuel tank. However,it was expensive and according to reviews I read, they seem to have problems tripping codes.
Instead, I modified my OEM roof rack to hold 3 (5) gallon plastic jugs. It works perfectly and only cost about $95 bucks total.

Great idea, a ladder might make this easier? Remember, that you are almost at the weight limit of the OEM RR as the fuel containers are about 150 lbs.

 

[targa88]

I have debated this issue for some time. Most of the point have already been covered.
So far I have resorted to extra Sceptre cans on the rear swingout bumper.
Although there is plenty of place underneath/behind the rear axle for an auxiliary tank. At this point in time there is NO reliable solution for the FJC. The MANAFRE tank (although sturdy/including bash plate only offers an additional 19 gallons) - still has issues with gaskets/filler neck causing error codes.
There is a theory - to cut out the OEM tank - have a custom tank built with the OEM "guts" (senders/gauge/baffles, etc). Unproven at this point in time.

Cons (aux tank)
Added weight that could not be easily removed when stuck
Not DOT approved - potential liability concerns

Cons: (Jerry Cans)
No efficient method to transfer fuel from jerry can to tank
Expansion of jerry cans in the heat - making it difficult to open and empty