Sta-Bil Fuel Stabilizer in the Rex tank?

[NAL]

:?: I don't see very much of the fuel in my Rex being used over the course of a year. Does anybody recommend using a fuel stabilizer to avoid the gas from going bad? Does anybody think it should be avoided?

 

[HomelessDude]

I add 2oz to each tank. Can't imagine a downside.

 

[ultraturtle]

Does anybody recommend using a fuel stabilizer to avoid the gas from going bad?

Absolutely. The rate of gasoline deterioration varies with many factors including heat, exposure to air, and alcohol content. BMW helps us out a bit with a pressurized fuel tank, but significant deterioration of untreated fuel still occurs in as little as one month. Add a 1/2 oz of fuel stabilizer per gallon whenever you fuel up.

Even treated fuel goes bad in about a year, so try to deplete the tank and refuel at least once a year.

Who'd have thought there could be an advantage of having a small gas tank? Less fuel to burn up and replenish.

 

[hrmandell]

It couldn't hurt if you let the gas stay for 3 months or more. Seems like a lot of trouble. Why don't you run the charge down and let the range extender do its thing every few months. Further, while basic no lead regular tends to be unstable over time, you could use premium as BMW suggests which won't deteriorate very quickly.

 

[ultraturtle]

The only difference between regular and premium gasoline is the addition of anti-knock compounds. Premium contains no more fuel stabilizing compounds than regular.

As a matter of fact, most premium gasoline will actually deteriorate more quickly than regular, because alcohol is one of the least expensive octane boosters, and it's use in a premium fuel will cause it to chemically break down more quickly than a regular fuel with a lower percentage of alcohol content.

That's an academic point, however. Suggest you follow BMW's recommendation to use premium fuel - it's what the engine was designed to burn.

 

[jadnashuanh]

At certain intervals, the i3's computer will turn the REx on for a short period to probably get the oil flowing and ensure things still work. This is not a daily or weekly thing...I do not know the interval, but it is more than a few weeks in between. So, even if you do not need or want to run the REx engine, it will be started and run periodically.

 

[ultraturtle]

At certain intervals, the i3's computer will turn the REx on for a short period to probably get the oil flowing and ensure things still work. This is not a daily or weekly thing...I do not know the interval, but it is more than a few weeks in between. So, even if you do not need or want to run the REx engine, it will be started and run periodically.

Jadnashuanh is correct. Per page 57 of the W20 Engine Document:

After a period of roughly eight weeks the combustion engine is automatically started... An automatic start is required to guarantee the operational reliability of the range extender.

Not that this matters a great deal for this discussion, as it only burns an ounce or two of gasoline during this maintenence run at idle power. Run time depends on the starting temperature of the combustion engine, and I've experienced only a couple of minutes of REx operation at moderate temps.

It should also be noted that any automatic or intentional operation of the REx engine restarts the ~8 week clock.

 

[mindmachine]

At certain intervals, the i3's computer will turn the REx on for a short period to probably get the oil flowing and ensure things still work. This is not a daily or weekly thing...I do not know the interval, but it is more than a few weeks in between. So, even if you do not need or want to run the REx engine, it will be started and run periodically.

For me it seems to run about once every 2 months and for only 12 minutes using only a minusquel ammont of gas.

 

[Joero]

Is there a way to run the gasoline engine without running the battery down? How often must the oil be changed? Is it easy to change the oil? Could I easily do it in my garage?

 

[CanisLupus]

If you do a search on 'REX Maintenance Cycle' it should reveal the details of the automatic running of the REX on a routine basis , if it has not run for some time .

 

[Tacfoto]

If you have a US model, you can run the REx if you code the car to have hold mode. Then under 75% battery and driving, you can run the Rex. European models can do this without programming.

You can also run the REx at home by putting the car in Emissions Inspection mode. This will run the Rex for 20 minutes or less if you turn it off. https://www.youtube.com/watch?v=-umDh9pRCYk

 

[jadnashuanh]

Is there a way to run the gasoline engine without running the battery down? How often must the oil be changed? Is it easy to change the oil? Could I easily do it in my garage?

The computer won't allow the REx to turn on unless the SOC is below 75%. Once it is activated, it will run some minimum amount of time to ensure that the oil and coolant heats up enough to prevent moisture accumulation which would degrade the oil. It needs some 'space' in the battery to put the electricity it will generate during that minimum time frame. There's probably a similar restriction on when you can run the emission test, but I am not positive.

You should change the oil when the computer tells you! BMW uses what they refer to as condition based servicing, and that takes into account the age and use pattern to decide when it is best to do that sort of thing.

 

[louisgrenier]

The only problem i have with my I3 since 3 years is the Rex showing notice that i won't start and that i can continue my trip only on electricity. Each visit to the dealer finish with locating the problem with the fuel being transformed to Jello. I don't use the Rex for months. Fuel is Shell V Max guaranteed to be ethanol free. Now they have to remove the tank to clean the bottom of it. When they will give it back to me, i will defenetly put some fuel stabiliser in it. I put fuel stabiliser in my Skidoo and they start perfect 9 months later. These Skidoo have a complex Rotax engine with emission control, and catalyser, and the fuel stabiliser does not seems to harm them. So i will go for fuel stabiliser in the i3.

Louis

 

[viking79]

Make sure to run the Rex regularly to avoid problems like this. I purposefully take a trip every month or so that uses a tank of fuel or two.

Ethanol fuel should not be a problem unless stored open to atmosphere, pressured tank should mean no water absorption issues that would lead to phase separation.

I have seen mixed reports on fuel stavilizers, not confident they actually help significantly. Maybe go research at bobistheoilguy.com and see what they say.