Lady recommended that a friend of mine use regular in his new 335i. She works at the dealer. Sounds like complete BS to me, but I don't know much about the 335i. Just wanted to confirm.

93 OCTANE for best results.Who would put 87 octane in a car like that?

if you can afford the 335i y not fork out the extra $.20-$.30 per gallon to keep your car running its best? especially since gas prices are dropping. Granted they are still high if you look at the past 5 years or so but its only $3.12 in PA for 91... use the highest u can get i would say

FWIW I have a 328 and experimented with premium and regular. I got 26.3 and 26.7 mpg using regular. I then tried premium for two tanks and got 25.1 and 25.4 mpg driving the same route under the same weather conditions.
I have a long steep hill near my home where I start from the bottom and use full throttle to a point near the top. On both premium and regular I was able to hit the same 190 kmh at the top.
I also tried this with my 2004 Nissan Pathfinder that also recommends premium fuel and got the same results. 21.2 mpg on regular and 20.7 on premium. 145 kmh on both up the same hill.

The difference between premium and regular is approx 50 cents a gallon in Canada.

I will be using regular on both vehicles from here on in.

you get better gas mileage in a car that requires 93 if you put 93 in it. If you run a lower octane in the end you are paying more

i wouldn't put 87 in a turbo'd car.

premium fuel is more knock resistant. cheap gas will detonate easier, and the DME will likely retard the timing to prevent it. turbo'd cars are more likely to detonate anyway, therefore, you should use premium.

i would never, ever put 87 in my RX-7. rotaries are extremely vulnerable to knock, and one good ping could spell the end of a rotary engine.

you get better gas mileage in a car that requires 93 if you put 93 in it. If you run a lower octane in the end you are paying moreWhat are you basing this statement on?

FWIW I have a 328 and experimented with premium and regular. I got 26.3 and 26.7 mpg using regular. I then tried premium for two tanks and got 25.1 and 25.4 mpg driving the same route under the same weather conditions.
I have a long steep hill near my home where I start from the bottom and use full throttle to a point near the top. On both premium and regular I was able to hit the same 190 kmh at the top.
I also tried this with my 2004 Nissan Pathfinder that also recommends premium fuel and got the same results. 21.2 mpg on regular and 20.7 on premium. 145 kmh on both up the same hill.

The difference between premium and regular is approx 50 cents a gallon in Canada.

I will be using regular on both vehicles from here on in.

Your approach is very methodical, but I see two issues. One is that the octane number posted on the pumps is a minimum, and any given tank could well be a higher octane rating. So it is difficult at best for us to know what is really coming out of that 87 octane nozzle and into our tanks.

Another issue is that if you are getting 87 octane you are dependent on the knock sensor detecting the onset of detonation and retarding the timing. Over the life of the car I would think that there are reasonable odds for one of these failing, leading to ongoing detonation (and engine damage) while using lower than specified octane.

And with regard to the original question, I have run into sales people pulling this line before in another car brand. Americans have a real aversion to buying premium gasoline, to the point that it costs German car dealers sales. (You see the same behavior with regard to other fluids such as oil, coolant, transmission fluid…). I believe that many of these dealers and their employees have convinced themselves that regular is “OK” in order to make their customers happy.

So it comes down to who do we trust? The German engineers back in the mother country, or the sales guy working on commission?

So it comes down to who do we trust? The German engineers back in the mother country, or the sales guy working on commission?


I trust the our alien overlords in the mother ship , I mean the German Engineers in the motherland, errr mother country :cyclona.

Nothing under 91 for just about any car, especially turbo'd, it'll knock like crazy!!

Don't use anything lower than 91 octane in a 335!

Start drinking Dunkin Donut coffee instead of Starbucks and spend those extra pennies on the premium gas instead! I am really surprised when people try to go cheap on gas when they have no problem paying through the nose for low quality alternatives just because of marketing and hype.
Here's a quick comparison:
Say you drive 12000 miles/year at 20mpg, so that is 600 gallons per year. Say premium is 30c extra per gallon than 87. The extra cost per year for premium is $180. Now say you also buy coffee every day but insist on starbucks instead of the cheaper equally good (if not better) coffee. Say the starbucks coffee is 50c extra per cup (I believe it is more), then per year (365 days) you pay the same amount of money (365*.5 = ~180) for no obvious benefit, but then balk at paying the same amount to ensure the proper performance of your car :nuts. I'm dumfounded!

Start drinking Dunkin Donut coffee instead of Starbucks and spend those extra pennies on the premium gas instead! I am really surprised when people try to go cheap on gas when they have no problem paying through the nose for low quality alternatives just because of marketing and hype.
Here's a quick comparison:
Say you drive 12000 miles/year at 20mpg, so that is 600 gallons per year. Say premium is 30c extra per gallon than 87. The extra cost per year for premium is $180. Now say you also buy coffee every day but insist of starbucks instead of the cheaper equally good (if not better) coffee. Say the starbucks coffee is 50c extra per cup (I believe it is more), then per year (365 days) you pay the same amount of money (365*.5 = ~180) for no obvious benefit, but then balk at paying the same amount to ensure the proper performance of your car :nuts. I'm dumfounded!

Very well put :thumbup:

Starbucks coffee is no more expensive than coffee from DD. I pay $1.80 for a Grande, and everywhere else it's the same price. It's actually way more expensive in a restaurant...I paid $5 for a cup of coffee from a french press the other day.

I live in a state that only has 91, if there was 93 around it would go in the tank every other tank.

if you can afford the 335i y not fork out the extra $.20-$.30 per gallon to keep your car running its best? especially since gas prices are dropping. Granted they are still high if you look at the past 5 years or so but its only $3.12 in PA for 91... use the highest u can get i would say
just filled up for $2.85 in Allentown PA, it's getting cheaper by the week. that said, I think the minimum is 91 for that car.

Why on Earth would you spend that kind of money on a performance vehicle and then try to cheap-out on fuel and then not get the performance you paid for? :banghead:

Folks:

Irregardless of what your opinions are, when it comes to a turbo charged car, you have to realized that this is a very sensitive engine. Why would you save the few bucks when you can afford the car and not let the car enjoy the premium gas that it is recommended to use.

Having said this, say for example you are flying a light aircraft and you have to land at a nearby airport to refuel. There's minimum services available at this small airport. The recommended fuel for your aircraft is AVGAS 100LL (being the lowest recommended grade).

Would you be prudent enough to haul down farmer Jones who watch you parked the aircraft next to his truck at the tarmac and take a ride with him to town to by the cheapest regular gas available at the closest airport gas station ? You know very well that the aircraft will be proned to perhaps an engine failure after take off or enroute to your destination?

So what's your decision ? Not that the engine will die right away but hey who knows when you are cruising along Route 66 in the middle of the California/Arizona freeway with no services, your engine could quit.

Turbos are so sensitive that they should be fed by the correct grade of fuel. In all fairness, why then bother to cool the engine down after a hard run before you switch off the engine ? These are all inter related care for a turbo charged engine. If you've own and driven a turbo charged car, you'll definitely know what the do's and don'ts are.

Enjoy your ride better with the premium gas. Watch your engine so you won't bust your wallet later.

I use 89 octane in my 328i; but I don't have 300 HP and twin turbos, so I would recommend 93.

Enjoy your ride better with the premium gas. Watch your engine so you won't bust your wallet later.

+1

For $3 per fill-up, isn't it worth getting the performance you paid for, and to not hurt those twin-turbos down the road? That's like buying one extra gallon of fuel, and if the car lowers performance you get less mpg - which costs you at least that extra gallon anyway!

i cant believe you even asked that question.... 91 man

Using less than required octane gasoline in a new-gen BMW will cause problems other than poor performance and lower MPG. It can damage the engine. This is especially true for the N54, but it also applies to the NA engines.

I wouldn't say that's true. Modern engines have knock sensors and pull timing.

I used Hess gasoline at 92 octane and the next day I went to start it and it took 3 to 4 seconds to turn over. I hate hess!

I used Hess gasoline at 92 octane and the next day I went to start it and it took 3 to 4 seconds to turn over. I hate hess!
nothing wrong with hess gasoline but the fact that your stations only carry 92 is enough for me to go hahas at your situation. :stickoutt

If the mfr says do it, I would do it. All you need is a voided warranty, I bet that'll cost a few pennies more.

nothing wrong with hess gasoline but the fact that your stations only carry 92 is enough for me to go hahas at your situation.

There is no situation. I hope youre not trying to feud with me for no reason. I really dislike that. I am here to share information and get information. Now what would you say to this.. when an old car tries to turn over for 3 to 5 seconds without starting this is the same thing my car did with that gasoline. Since then I've used Exxon or Shell and it never did it again. That is why I believe Hess is bad quality. Now what do you think about that?

There is no situation. I hope youre not trying to feud with me for no reason. I really dislike that. I am here to share information and get information. Now what would you say to this.. when an old car tries to turn over for 3 to 5 seconds without starting this is the same thing my car did with that gasoline. Since then I've used Exxon or Shell and it never did it again. That is why I believe Hess is bad quality. Now what do you think about that?
not at all. I don't know you nor do I care to start some e-drama with you. lighten up and enjoy the forum.

your situation leads me to believe that the particular station has either poor quality control for their tanks which probably have water or other contaminants or they received a low quality load from the local distribution center or the truck carrying the fuel was already contaminated.

as you probably know, all gas stations receive their fuel from a small group of centers. odds are that the shell, exxon and hess stations in your area receive their fuel from the same center.

it's not Hess, the blame lays some where else. that's what I think about that. ;)

-Ron

(Standard disclaimer: the next couple paragraphs of info come from a recent article on gasoline refining and distribution in USA Today. Take it with as large a grain of salt as you feel necessary.)

Yes, all trucks fill up at the same fueling centers. There is a huge flow line that can be set for each of the wholesalers' which dumps a prescribed amount of detergent and other additives into the tank as well. So the driver pulls up, selects the octane rating, selects the brand, loads the fuel, and is on his way. The additives and detergents mix while the truck is moving (although they don't "dissolve", per se, sitting in the tanks at the local gasoline station does allow sediment to settle, so don't fuel up the day before or the day of the delivery truck).

That means that the basic fuel is the same for all of the brands. They differentiate based on additives.

Having said all that, I used regular or mid-grade on my Supra all the time. I only had two problems related to the engine after 135k miles: the shaft on the second turbo broke, and the valve seals started leaking. Neither of those is caused by low octane fuel or predetonation (well, the leaky valves could be a symptom, but the mechanic that redid the valves said the plugs, valve covers, and other parts showed no sign of predetonation).

For the first 100k miles that car was autocrossed once a month on average, hitting the rev limiter on many courses, often on multiple runs (so figure 7k rpm 6-10 times on a single day per month, sometimes double that for a Sat/Sun autocross event). And this was typically at 15-19 lbs of boost (stock was 11.5). Of course, Toyota got a reputation for over-engineering that car because of the effort they put into that drivetrain...

I also did the mileage test and determined that I had such a small difference in mileage between mid-grade and premium and that it didn't pay to put premium in.

I'm not saying that it's okay to do it. I'm saying that my previous car survived it just fine. And that's only a single data point out of 12k+ of those that were imported into the U.S.

I posted in another thread the contents of my owner's manual regarding octane ratings. Since finding those pages, I typically fill-up with mid-grade (either 89 or 90 around here) and haven't seen any problem.

YMMV. (Seemed appropriate. :))

just filled up for $2.85 in Allentown PA, it's getting cheaper by the week. that said, I think the minimum is 91 for that car.
hey neighbor.

I used Hess gasoline at 92 octane and the next day I went to start it and it took 3 to 4 seconds to turn over. I hate hess!

Tell Al Gore, he is or was a board member.

Out of my 335i owners manual. States that fuel with minimum of 89 AKI may be used. However the manual also states that "Should you encounter drivability problems which you suspect could be related to the fuel you are using, we recommend that you respond by switching to a recognized high-quality brand such as is advertised as Top Tier Detergent Gasoline. Failure to comply with these recommendations may also result in unscheduled maintenance." I interpret that to mean out of your pocket. I have elected to spend a few cents more for the Top Tier.

Well, flame away but I've used 87, 89, 91, and 93. There is no difference. I drive like a raped ape so the engine sees some load with each type of fuel. If it makes you feel better use 93, if you want to save some money use 87. I used regular for most of the summer here and just recentl switched back to premium (price dropped and I figured what the hell).

and just recentl switched back to premium (price dropped and I figured what the hell).
That's exactly the point, for an extra 200$ or less a year, what the hell.

I think the issue is simple, if you lease you buy the cheapest and let the poor buyer later pay the penalty. If you purchase and plan to keep, you are probably a little more concerned about fuel quality.

I would never run 87 in a turbo car... that is just asking for trouble. My car runs like crap on 87. The DME must have retarted the timing a bit because it would downshift going up hills where it normally would pull in OD. Lacking power in an already power challenged car is not a pleasant experience. However, I can not tell a difference between 89 and 93 so I run 89 which is the minimum octane rating for the M44.

I think the issue is simple, if you lease you buy the cheapest and let the poor buyer later pay the penalty. If you purchase and plan to keep, you are probably a little more concerned about fuel quality.Wow... that is a douchebag mentality to have.:rolleyes

Well, flame away but I've used 87, 89, 91, and 93. There is no difference. I drive like a raped ape so the engine sees some load with each type of fuel. If it makes you feel better use 93, if you want to save some money use 87. I used regular for most of the summer here and just recentl switched back to premium (price dropped and I figured what the hell).Just OOC, why did you switch back to premium?

Wow... that is a douchebag mentality to have.:rolleyes
+1, treat the car with respect even if leasing (and so the next owner).