Does the rex required regular or premium fuel?

[philly10]

As above....thanks in advance.

 

[Jeffj]

Premium

 

[displaced1980]

I use 95 Ron standard.

It's a generator after all.

 

[janner]

For the UK, just regular unleaded will do.

 

[philly10]

Thanks guys.

 

[imolazhp]

The owners manual says minimum of 89 octane, recommends 91 octane and not to use more than 10% ethanol. I buy at a specific station that sells non-ethanol, 100% gasoline. Sometimes its 91 octane, sometimes its 93.

 

[SteveMondragon]

I'm probably the only cheapskate here who buys and puts in 87 (at still around $3/gal where I live, while the rest of the US is around $1 ~ $1.50/gal).

Haven't had any issues, nor do I care since the car is leased and under full warranty should something happen.

 

[imolazhp]

I'm probably the only cheapskate here who buys and puts in 87 (at still around $3/gal where I live, while the rest of the US is around $1 ~ $1.50/gal).

Haven't had any issues, nor do I care since the car is leased and under full warranty should something happen.

Yeah, it's too bad the car can't tell on you, instead you'll pass along long-term problems to the second owner. This is yet another reason I want my own car after my lease is up and not someone else's lease return.

 

[jadnashuanh]

Extended use at high loads (high speed travel is the likely situation) would mean the computer control would need to reduce the maximum power available by detuning the vehicle when using 87-octane fuel, otherwise, it would be pinging like a 2-year old on symbols, or burning the valves or piston head. These things are designed to operate in a certain manner, and can only protect themselves from cheapskates, or the ignorant for so long!

 

[brorob]

I use premium, in fact I use premium in all of my small engines (lawn mower, snowblower, chainsaw) because the higher octane is better for them. Plus with the very little amount of fuel I use it's not costing me much more. Definitely avoid using fuel with ethanol if possible, which is especially bad for small engines.

 

[jadnashuanh]

Higher octane fuel contains more additives, which, in addition to raising the octane level, helps keep things cleaner by their detergent actions. But, in general, using a higher octane fuel than the engine was designed for doesn't really pay you much as opposed to too low of an octane rating which can damage an engine. If you're lucky, you can buy gasoline without added ethanol, but there are a number of states where that is impossible. Ethanol lowers the energy content per volume, meaning that you'll take a hit on fuel economy. And, because ethanol has an affinity for moisture, an open system (the REx's is closed), can be a problem.

 

[imolazhp]

I may not have any DCFC's within 3 hours of me but I do have a non ethanol station near me.

 

[MarkN]

Two days ago the range extender on our 2015 i3 refused to turn on and the battery died two blocks from our house. We got the car back this morning. It had had five different error codes, one of which was for an engine misfire. Our service advisor said that BMW is now recommending 87 octane gasoline for i3s used at high altitude like in Colorado to prevent misfires. Apparently lots of REx owners in Colorado are reporting misfires. In November misfires illuminated our check-engine light.

 

[alohart]

Apparently lots of REx owners in Colorado are reporting misfires. In November misfires illuminated our check-engine light.

It's amazing to me that a low-output engine running at relatively low speeds would suffer from misfires. Does a similar engine in a BMW scooter suffer from misfires? It probably does but doesn't run under such stringent emission requirements that probably require that misfires set diagnostic trouble codes.

 

[jadnashuanh]

While higher altitude lessens the need for premium fuel (unless you have a turbo), I'm not sure why that is related to misfiring if used. I wonder if, because the fuel in the REx may be old from non-use, that people may have 'winter' fuel in it still once it warms up, verses 'summer' blended fuel when actually needed or vice-versa. Might be a good practice to just run the REx's tank dry (well, as dry as the computer will let you!) periodically, and refilling with fresh stock might help. 'Summer' blended fuel has less volatility, and might be harder to ignite if it's cold out.

 

[MarkN]

While higher altitude lessens the need for premium fuel (unless you have a turbo), I'm not sure why that is related to misfiring if used. I wonder if, because the fuel in the REx may be old from non-use, that people may have 'winter' fuel in it still once it warms up, verses 'summer' blended fuel when actually needed or vice-versa. Might be a good practice to just run the REx's tank dry (well, as dry as the computer will let you!) periodically, and refilling with fresh stock might help. 'Summer' blended fuel has less volatility, and might be harder to ignite if it's cold out.

At least in my case old/non-seasonal fuel shouldn't be the problem. I drive our i3 on a 110-mile trip once a week and need to re-fuel every 2 to 3 weeks.

 

[bwilson4web]

Having gotten a copy of the Owner's Manual, they list 89 as the lowest allowable. This makes sense as in the i3, the engine HP is listed at 34 hp compared to +60hp in the motor scooter. But I'd rather get some metrics before doing any extensive operation below 89.

Near as I can tell, the engine lacks a knock sensor that would allow the controller to handle lower octane fuel. But 89 (aka., plus) makes sense.

Bob Wilson