what octane is recomended

[nasty50]

guys 88 325e bone stock whats the recomended octane for it thanks..

[xwill112x]

87.


91 or 93 if chipped.

[NeoMishMoo]

xwill112x pretty much said all there is to say.

My old roomate's dad owned an oil company and he sweared that higher octane got better mileage, but I tested it a lot and it seems like the very slight increase in mileage makes no difference when you calculate the higher cost.

[Adrian_Visser]

The interwebz did a test on some newer vehicles with knock sensors that could theoretically adjust ignition timing to take advantage of higher octane fuel, turns out on most it made no difference and on some vehicles (honda CRVIi wanna say) the gas mileage was worse than with 87. Save your money and just use 87.

[NeoMishMoo]

however I have noticed that cars run worse on the really cheap gas stations (for example wal-marts around here that have Murphy's gas stations). Didn't notice as much a difference on my e30 but my dad's 80's volvo would run like shit on that gas. Just go for big chain gas stations.

Even though I don't believe a bit of the crap that shell is trying to sell with their new nitrogen gas.

[nasty50]

Thanks guys

[dont have one]

chevron. 87 or 91 octan

[Surtr]

chevron. 87 or 91 octan

I kept running Chevron 91 octane cause I found it gave me better gas mileage than any other brand I had used. Turns out it was just Chevron, not the 91 octane. The reason behind that is that Chevron is pretty much the only station around here that isn't using 10% ethanol. Our cars prefer 100% gas. And gas has more power per gallon than ethanol.

I've heard that 91 octane can actually cause harm to the engine by detonating later and not as completely. I had like 1/8" of an inch of carbon deposits on all my pistons when I took the head off a couple years ago. My dad seems to think it was caused by the 91 octane. I'm prone to believe it was just the 300k on the engine.

[rThor432]

87.


91 or 93 if chipped.

Yep.

Short story about my experience with this subject--

After years of fueling my E36 and E46 with 91/93 I had got myself stuck in the habit of reaching for the premium every time I went to the pump. I bought an '86 325e after not owning an E30 for a long time and kept filling it with premium like my other cars for months. One day, they were all coincidentally low on fuel, so I filled them all up. After spending $100+ to fill up the other two my daily fuel budget was nearly blown, so I decided to see how the 325e would react to 87 octane fuel. To my surprise, it actually ran better and I got better mileage.. Wierd, but true. The performance increase over 91/93 octane was very noticeable.

[blueapplesoda]

techincally, 87 octane fuel is more explosive than 91 octane, thus more energy held in the molecules and its bonds. unfortunately, it is also unstable which is why we use higher octane as a way of controlling detonation on cars that require premium fuel. Higher octane fuel burns slower, and is less explosive. It will still make the same power, but the engine has to be tuned (ignition advance much) for the fuel; like forced inducted engines, and factory tuned "premium fuel only" engines.

the eta has a very conservative ignition map, so fast burning fuels are a plus for the eta.

[txtorquemade]

Wow...didnt know all that. Think Ill switch back to the 87.

[bmwdude]

Use whatever the factory recommends on a stock engine, it doesn't get any simpler then that. If your "newer" car is rated for 91AKI, and you add 89, the factory knock sensors and ECU will simply retard the timing, and you won't get the full potential of the engine, as was meant by the engineers. Buying a Porsche Cayenne, Audi S4, BMW M3, etc, to add 89 octane to save a few bucks just doesn't make sense. The ecu is capable of retarding the timing, that it is.

Vice versa. Don't throw money on 91AKI, when your tuning is meant for 87AKI on your ETA ;).

It's your wallet at the end of the day. ;) Do what you want with it. The advice is there to steer you properly.

[Tbolt]

i run 93 octane exxon/texaco/shell

w/bav auto chip

[Gadea]

my E30 has a factory sticker on the gas door that says only to use 93 octane, and I went by that. However, I completely agree with NeoMishMoo. I have experimented with my other cars/trucks I´ve had, and the difference is not as much in the octane as it is on the gas station where you fill up the tank. I have a detailed excel file with data showing gas mileage over time using different gas octanes. In my case, shell and bp gas stations have shielded best results. I can notice the car pulling harder.

[b*saint]

I run 92 in my bike (+4 degree advance on timing and leaned out from 180 to 170 main jets.) 91 is min recommended stock and I think 93 wouldn't have as much ooomph.

Thus you should run the minimum recommended octane for your setup.