Gas

[OldHubbardRd]

What octane gas do you run in your X5 3.0?? Would you use 93 octane one week and mix 87 or 89 here and there?? With gas prices the way they are it can cost a bunch to fill these. I have used 89, 91 & 93 and did not notice any difference and did not get better or worse gas mileage. I have always had a hesitation problem that I have not had time to bring the car in for repair. This hesitation happens whether I'm using 89 or 93. I do not thing my hesitation problem is gas related.

[Kzang]

Use 91 octane as per your manual.
Use 93 or higher if you feel that you want to waste your money OR if your local station doesn't offer 91 and only 93 or higher.
Use 89 octane if you just don't care about your car.

Nothing else can be said about this topic.

[cross5x]

Personally, I love the car too much to feed it other than the 93 (the most expensive one)

[Llando88]

X3 3.0Si here (same engine); 91 octane exclusively.

[cross5x]

is 91 the highest? I forgot the number, I just use Shell's V-Power.

[Craig B]

93 is the highest around here at BP...

Craig

[cross5x]

So V-Power should be 93 right?

[pauljordantx]

From www.shell.com (specifically http://www.shell.com/home/Framework?siteId=us-en&FC2=/us-en/html/iwgen/leftnavs/zzz_lhn3_4_0.html&FC3=/us-en/tailored/shell_for_motorists/fuels/optimax/optimax_faqs_ga_1602.html)

"What is the octane rating of Shell V-Power?

Octane ratings for premium gasoline vary across the country. The octane level of Shell V-Power is anywhere from 90 to 93 octane, depending on the region."

So, check the pump when you fill up.

At most gas stations there are three different unleaded choices (that vary in octane). If you're filling up with the highest octane available, you're at least meeting BMW's recommendation of 91 octane. For some stations, the highest octane available may exceed the recommendation.

As to whether you need to meet the recommendation or not: I view that as a debate that has no objective answer. The vehicle 'should' run fine on lower octane, but probably not optimally. I decide to meet the recommendation because I want the vehicle to behave the way BMW intended it to, and I trust that BMW would not make unneeded and wasteful recommendations. Also, as gas prices go up, the percentage difference in price gets smaller :)

[cross5x]

Thanks for the info :thumbup:

Is there a performance difference between the 91 and 93?

[Craig B]

I would use the best name brand fuel in your area...

Craig

[MTech8]

Does anyone know anything about gas sold at Costco?

I've always been proned to use name brand, but Costco gas is very tempting. 91 octane for 20-30 cents less than 91 octane at brand names around the area.

[dfrith]

BMW and some other manufacturers recommend that you use Top Tier Gasoline's.

Here's the link:

http://www.toptiergas.com/

TOP TIER Detergent Gasoline is the premier standard for gasoline performance. Six of the world's top automakers, BMW, General Motors, Honda, Toyota, Volkswagen and Audi recognize that the current EPA minimum detergent requirements do not go far enough to ensure optimal engine performance.

Since the minimum additive performance standards were first established by EPA in 1995, most gasoline marketers have actually reduced the concentration level of detergent additive in their gasoline by up to 50%. As a result, the ability of a vehicle to maintain stringent Tier 2 emission standards have been hampered, leading to engine deposits which can have a big impact on in-use emissions and driver satisfaction.

These automakers have raised the bar. TOP TIER Detergent Gasoline help drivers avoid lower quality gasoline which can leave deposits on critical engine parts, which reduces engine performance. That’s something both drivers and automakers want to avoid.

TOP TIER Gasoline Retailers:

QuikTrip
Chevron
Conoco
Phillips
76
Shell
Entec Stations
MFA Oil Company
Kwik Trip/Kwik Star
The Somerset Refinery, Inc.
Chevron-Canada
Aloha Petroleum
Tri-Par Oil Company
Shell-Canada
Texaco
Petro-Canada
Sunoco-Canada

[Llando88]

Does anyone know anything about gas sold at Costco?

I've always been proned to use name brand, but Costco gas is very tempting. 91 octane for 20-30 cents less than 91 octane at brand names around the area.

I suppose it varies by region. :dunno:

I use Costco gas to fill up either the 330i or the X3. They seem to pump so much gas through there that I am sure it's fairly fresh gasoline.

[Bruin72]

I used to believe in only using top tier gasoline until I started consulting three years ago right near a CITGO gasoline terminal, where I observed trucks of every brand of gasoline, except Shell, coming out of there. It was then I decided that it didn't really matter.

[uncle ken]

Is there a performance difference between the 91 and 93?
No. Octane rating is about how easily the fuels ignites, not the energy released.

[pauljordantx]

No. Octane rating is about how easily the fuels ignites, not the energy released.

Yes, but my understanding is that the amount of energy released that is translated to rotational energy of the driveshaft is dependent on how easily (or not easily) the fuel ignites. Vehicles with contemporary engine management systems will adjust timing based on fuel octane such that lower octane can result in lower engine performance. The engine still runs, but with less power.

[uncle ken]

Yes, but my understanding is that the amount of energy released that is translated to rotational energy of the driveshaft is dependent on how easily (or not easily) the fuel ignites. Vehicles with contemporary engine management systems will adjust timing based on fuel octane such that lower octane can result in lower engine performance. The engine still runs, but with less power. A fuel with an octane rating lower than spec tends to pre-ignite; to explode while the piston is still on the upstroke. If you visualize this it is easy to see why this is more of a problem in the confined spaces of a high compression engine. The ECU tries to prevent this 'knocking' by delaying (retarding) the spark until the piston has passed the top of it's stroke. If ignition occurs before the piston reaches the top of it's stroke, pushing against it; or if ignition is delayed until the piston is already on the downstroke, lowering the compression at time of ignition, there is a reduction in the amount of energy transferred to the crankshaft.

But the amount of energy released by the fuel remains independent of octane rating.

[brydon]

top tier gasoline retailers might use other trucks to deliver their gasoline, but it's all supposed to be their gasoline, it's all supposed to meet their standards for additives and quality. Using a cheap, non-top-tier gas will cause buildup in your engine over time and decrease your engine's life and performance capability. You could use Techron or some other fuel-system cleaner once in a while to burn off the additives, but why cycle your engine through crap condition to good condition and back again.

As for the octane thing, all modern engines compensate for the reduced octane by modifying the timing etc. The problem is, if you get on the gas REALLY hard it's possible that if you're not using the correct octane your engine computer will not be able to respond in time and you'll get some knock or ping - bad news for your engine.

If you MUST save money, the safest thing to do would be to run 1 tank of premium gas for every 1 or 2 tanks of cheap gas, but never skimp on the octane, always use the closest to the manufacturers recommended grade you can get.

[MTech8]

Can use of non-top tier gas which lead to build up cause cyinders to go bad?

My father-in-laws car started shaking and driving irregularly. When he took it in, they told him that his cylinders went bad and needed to be replaced. I'm wondering if bad gas could have attributed to this problem? He had about 100K on his car.

[pauljordantx]

A fuel with an octane rating lower than spec tends to pre-ignite; to explode while the piston is still on the upstroke. If you visualize this it is easy to see why this is more of a problem in the confined spaces of a high compression engine. The ECU tries to prevent this 'knocking' by delaying (retarding) the spark until the piston has passed the top of it's stroke. If ignition occurs before the piston reaches the top of it's stroke, pushing against it; or if ignition is delayed until the piston is already on the downstroke, lowering the compression at time of ignition, there is a reduction in the amount of energy transferred to the crankshaft.

But the amount of energy released by the fuel remains independent of octane rating.

OK, but the original question was, 'is there a performance difference?' Admittedly, not a very precise question, but I have to assume the poster wanted to know if his vehicle will see a performance difference when running on a different octane fuel. So yes, the energy released by the fuel is the same (probably, assuming no other factors come into play), but the vehicle can have different performance on different octane fuels.

[rh71]

20 cents difference between 87 and 91/93 usually. $4 more per fillup. If you fill up once a week, that's only +$200/yr. Is it really that much of a factor?

[cross5x]

OK, but the original question was, 'is there a performance difference?' Admittedly, not a very precise question, but I have to assume the poster wanted to know if his vehicle will see a performance difference when running on a different octane fuel. So yes, the energy released by the fuel is the same (probably, assuming no other factors come into play), but the vehicle can have different performance on different octane fuels.



This is just what I was looking for :thumbup:

Thanks :bigpimp:

[riod007]

i have an 07 x3 3.0si and u always run 91 and monthly i will run a tank of unleaded vp 108 when i want some more guts

[rlengyel]

I have a new 535xi with about 600 mi on it. While still on the first tank of gas I bought (Get-Go 93 octane, Pittsburgh SW PA), the car began running roughly when called upon to accelerate, and I got an engine malfunction warning, reduced power. The warning stated we could continue with caution, so we continued on to the Phila-Wilmington area. After lots of searching and using BMW assist, we found...

UNION PARK BMW, WILMINGTON, DELAWARE.

THANKS TONS TO GEORGE AND GREG. EVEN THOUGH THEY ONLY DO APPOINTMENTS ON SATURDAY, THEY EVALUATED MY CAR. ON SATURDAY 5 JULY 2008!!! NO OTHER SERVICE DEPARTMENT IN THE PHILA-WILMINGTON AREA WAS EVEN OPEN THAT DAY!!! THANKS GEORGE AND GREG!!!

The computer revealed only misfiring, with all components registering OK. In their experience, and with the computer readout they had, they felt it was the gas. They felt the ethanol level may have been too high. I have bought gas from that Get Go station for years and have never had a problem with my Acura, Volvo, or Subaru.

So ... since the tank was at about one-quarter, we filled up with a top tier gas and a bottle of BMW fuel additive. CURED!!!

I've never given much consideration to gas other than octane. But this episode sparked my interest.

[Craig B]

I only run name brand fuel in my car. BP 93 octane. I have heard of too much alcohol in fuel before.

Craig

[GoFastNow!]

I always use 91. I never mix in lower octane gas to try and save a few cents. Why try to save few cents per gallon compared to (even the remote possibility of) ruining a $15,000 engine?

[dcharnet]

My research indicates that it does not harm any modern road car like the X5 to use a lower octane (but still high-quality) gas. I use regular in my '08 3.0 unless I am towing my sailboat, race car or motorcycles, or driving in the mountains. For those occasions, I like the extra HP that the higher octane brings. I do notice some difference in acceleration with 87 octane gas, but not enough to bother me. I have 12,500 miles and the car runs fine.