what octane do you use?

[m3f_bmw4life13_0098c1d2b1]

I just filled up the tank on my new m3 for the first time with 93 octane and the car seems to run much smoother. I think the dealer used low octane gas on my car because it sounded like a freakin train whenever i would start it. what do you guys use and have you noticed any difference between the type of octane

[m3f_Brent_Vino]

i've always used 93 octane on my bmws. with software, you'll have to use 91 or higher.

[m3f_Sirius_880bd69485]

Yeah. Our cars like high octane. But they won't really benifit from anyting higher than 93 unless you have software done to it.



And our cars always sound like trains off of a cold start. :P



Oh, I use 93 at all times. And I try to stay with one gas company. Either exxon or mobil. Arn't the one in the same anyways?

[m3f_////\/\ark]

I use 93 and have always done so. Sirius, Exxon and Mobil are indeed the same company. But I wouldn't worry about sticking to one particular company, regardless of what it is. Gas companies regularly buy/sell/trade gas amongst each other, so you could be filling up at an Exxon station with gas that was once bound for a Shell station. It's all the same pretty much. And even if there are small differences, you're not guaranteed to get the same company's gas from one gas station trip to the next.

[m3f_romh_9db5ad5d95]

I have to disagree with Sirius on the gas issue and agree with ark. Gas companies end up buying gas from different companies etc.. Specially here in Florida where there are no refineries, gas companies buy gas from the same supplier sometimes. If you're putting gas at the Mobil station for $2.30 / gallon for example, you could be paying much higher than the mom and pop store down the road which sells the same gas for $.20 cheaper. That;s why I don;t pay attention to gas brands and simply put gas where its the cheapest. The governemnt regulates gas stricly and certain minimum standards have to be met for all gas companies. So there is no bad gass! I know all this because my Dad has been in the oil business since I was born and in certain times has been in charge of the buying and selling of domestic gas. I have always put the lowest octane on all of my BMW's. Since 1992 with a 325is. They have all ran perfectly with the lowest octane. My M3 has 108K miles and has always run with 87 octane and it starts very smoothly, idles perfectly, and runs just at strong as when I have tried 92 octane. For me its a big waste of money . I know that 98% of the people here would diagree, but oh well!

[m3f_romh_9db5ad5d95]

By the way. Have any of you noticed that the M3 manual says the following:

" Because the engine-management system in these cars incorporates predetonation-detection (knock sensors), you have the option of using fuels of different specifications.

Minimum requirement; umleaded regular gasoline (87 AKI).

Higher octane fuels (premium unleaded, 90 AKI; super premium, 92 AKI) will provide slightly higher levels of fuel economy and performance. "



Octane is a general term used to indicate a gasoline's ability to resist engine knock. So if your engine doesn;t knock with 87, I don;t see a problem with using it.

[m3f_////\/\ark]

hehe... it's Mark, not ark. The /\/\ is an 'M'.



But yeah, the only reason I run 93 octane is because I have AA software that is (supposedly) optimized for it. Plus it's sort of habit at this point. But like I mentioned, I don't care *where* I get that 93 octane gas. It's all the same.

[m3f_romh_9db5ad5d95]

hehe... it's Mark, not ark. The /\/\ is an 'M'.



But yeah, the only reason I run 93 octane is because I have AA software that is (supposedly) optimized for it. Plus it's sort of habit at this point. But like I mentioned, I don't care *where* I get that 93 octane gas. It's all the same.



Sorry for the mistake. Yeah, if you have the software, then I understand. Mines 100% stock though. How do you like the AA software. They're down the road from me.

[m3f_////\/\ark]

To be honest, I haven't really felt much difference. Maybe I'm bad at judging slight increases in power or something. But one thing is for sure, it wasn't worth the $350. I seem to be in the minority of people who are dissatisfied with it, so maybe I got a dud or something. :hmm:

[m3f_romh_9db5ad5d95]

oh yeah. Sorry to hear that. But I;m sure you'l pull away from a stock m3 by at least half a car length or something.

[m3f_crunchynoodles]

Most of the gas companies in California sells 91 octane as their super. I think is the stricker clean air requirements. There is a local refinery who sells 100 octane racing gas for $4.50 / gallon right from their supply yard. I don't know if its worth the extra $2.50 / gallon to try. I'm still running stock. Anyone had try the 100 octane gas?

[m3f_M-avant_0baeb1c2f5]

I have ran the 100 octane on my A4 - helps with detonation issues on a forced induced car, specially in warmer weather. no 100 octane on the M - only on track days; not a performance thing really - just insurance on warmer days. I see more of a performance gain with the turbo'd car - only because it can run higher boost. the M runs on CA certified 91 octane. :-)

[m3f_reefer157_a2694f778b]

I thought that I read in my manual that 91 was the minimum recomended octane rating. I was filling up at a station in town here for a few weeks and I bagan to notice my fuel economy and power decreased by at least 25%. I was trying to figure out why, because the gas was about 15 cents a gallon cheaper, so one day I was at the pump and noticed this discrete little sign that said that their fuel contained like 10-15% ethanol.



It was 91 octane but it was slightly ethanol, maybe why it was cheaper, but definitely the cause of my power and economy issues. I began filling at the Chevron and within a couple of tanks my performance was back to normal.



Anyone ever use those fuel system cleaners? I have heard that they work but I have also heard that they ruin your seals and stuff, don't quite know what to believe.

[m3f_crunchynoodles]

Yeah I 've used the those fuel system cleaner once every 10K miles. They work great. I put in a bottle when it's almost dry. Then just fill-up with about 5 gallons of super.

[m3f_M3 powerrr.....]

In Holland we have an octane of 95 and 98.

The M3 runs on 98 !



We also have Shell V-power, that gives an octane of 98+, I guess near 100.

I also use powerpills in combi with an octane of 98, the pills upgrades the octane also.