Fuel for 35i

[sirajkas]

What grade fuel are you guys using? I'm using 93 octane and I get 14.9 mpg on my x35i...

[r33_RGSport]

I'm on 91, thanks to CA law. Been getting 16mpg. 85% street 15% freeway.

[Artdnj]

18+ on 91 octane, mostly city, about 40 percent highway. Comfort mode 90% of time. 3000 k and growing. Mileage in erased dramatically at north of 2000k

[sirajkas]

I'm going to switch to 91 and see if it makes a difference. I have tried Eco mode and it's still gives 14.9. I'm not sure if mpg is affected by the fuel contamination issue I had few months ago..

[Jsimon]

91 to 93 octane. 90%highway. 20.3 mpg

[42pilot]

Technically, you can put whatever you want into the tank. The engine has knock sensors that will detect if the engine is running poorly (knock detector) on the lower octane fuel and immediately retard the timing therefore reducing the risk of detonation (knocking a hole in the top of your piston). The price you pay is reduced performance and if you damage the engine, you pay for it, not BMW. One last point - since your motor is direct injection, use only name-brand fuel that has proper detergents and high quality additives, otherwise the direct injection system in these motors will foul intake valves. Now that is a VERY expensive repair you will have to pay. But I don't think you would buy a $65k car and be that cheap to dump corner convenient mart crap fuel in it...

[Kzang]

Originally Posted by 42pilot

Technically, you can put whatever you want into the tank. The engine has knock sensors that will detect if the engine is running poorly (knock detector) on the lower octane fuel and immediately retard the timing therefore reducing the risk of detonation (knocking a hole in the top of your piston). The price you pay is reduced performance and if you damage the engine, you pay for it, not BMW. One last point - since your motor is direct injection, use only name-brand fuel that has proper detergents and high quality additives, otherwise the direct injection system in these motors will foul intake valves. Now that is a VERY expensive repair you will have to pay. But I don't think you would buy a $65k car and be that cheap to dump corner convenient mart crap fuel in it...

According to the manual you can use 89 octane with no damage to the engine... Another thing about using lower octane rating than recommended will reduce mpg performance... Also cheap corner convenient mart crap? Do you know where gas comes from? Some of the top tier gas are those cheap corner convenient mart...

[LowerEast]

I use 93 octane. I'd use 91, but I rarely if ever see that as an option. I've gotten 20.9 mpg through 5,000 miles of mostly highway driving.

[42pilot]

Originally Posted by Kzang

According to the manual you can use 89 octane with no damage to the engine... Another thing about using lower octane rating than recommended will reduce mpg performance... Also cheap corner convenient mart crap? Do you know where gas comes from? Some of the top tier gas are those cheap corner convenient mart...

Then go for it!

Remember, most of them buy from the cheapest sources. But I don't care - it's your car.

[Kzang]

Originally Posted by 42pilot

Then go for it!

Remember, most of them buy from the cheapest sources. But I don't care - it's your car.

LOL... I have been driving BMW's since 2006 with my 2007 525i, 2010 535i, and now with 2013 X5 35i I have had no issues.

[mattsnow]

I have had a number of gasoline retail clients over the years and the operational guys will all tell you that almost all gas in pretty much the same. It all comes from a limited number of refineries, and it all has to meet the same stringent standards that ensures that it is all pretty much the same. Brand gasoline stations try to convince you that they have proprietary additives that are better and justify a higher price, but this is all marketing. That they offer you three "grades" of gas is mostly marketing too, but that is another story. With the implementation of RCRA, all stations are now using good tankage and piping. Even the variation that one used to see between a low-volume and a high-volume operation is gone because the low volume operators are out of business.

So yes, the quickie mart gas is just as good. All you have to do is make sure that the octane rating exceeds the car's specifications.

[42pilot]

We'll agree to disagree. I've torn motors apart that use corner station's fuel consistently and the carbon build-up on the piston domes, intake valves and plugs is significantly more. To clean motors with light carbon build up, I use Techron. A couple of tanks will clean the motor. Since Chevron/Texaco use Techron, I chose to use these name brands because of their additives that work, based on my first-hand knowledge and not marketing. But again, use what you want.

[Kzang]

Maybe in the 1970's... we live in the year 2014

[Barbja]

I put in Premium (whatever that happens to be at the station I'm using). I just focus on the gallons and avert my eyes from the $$. However, gas in Texas is 'cheap' compared to a lot of places, like CA or Canada (oh my!). Driving by stations in Canada and converting the $/liter to $$/gallons in your head is horrifying! Makes me want to drive an electric car.

[ramsal]

Originally Posted by LowerEast

I use 93 octane. I'd use 91, but I rarely if ever see that as an option. I've gotten 20.9 mpg through 5,000 miles of mostly highway driving.

20.9 is great. I'm at 16.9 with fairly even split between highway and city (but almost always in rush hour) and this is the lowest it has been after ~14,000km.

Unfortunately no 2014 35i X5s users registered on http://www.fuelly.com/ so can't compare with others.