What octane is everyone running on their cars? I know the minimum is 87 octane, with 91 recommended and 93 recommended for M cars.
I’ve ran 87, 89, and 93 octane and have felt no performance difference. Also, I don’t hear any knocking on any octane thanks to the knock sensors.
Car is a g20 m340i with a b58.
No one is telling you exactly why you should fill up with 91+ instead of 87. I’ll try.
Your engine runs a high compression ratio and a turbocharger, which requires fuel that doesn’t self ignite under high pressure. Higher the octane level, higher the pressure required for self ignition. So if your car states you need 91 and you use 87, your fuel is igniting before the spark plug even lights up (or midway during the compression stroke). This adds excess heat and stress on components in and around your cylinders.
“ECUs are smart enough. They adjust” - how does an ECU alter the compression ratio? Compression ratio is a function of bore and width of the cylinder and stroke length of piston. ECU alters other parameters trying to ‘minimize’ the risks. It’s supposed to be a failsafe and not for regular operation. In any case, your engine is running in less than ideal conditions when you fill up with 87.
Hope this helps.
Only Top Tier 93. Luckily Costco gas is Top Tier.
Idk why you’re getting downvoted you are right.
For the others, Top Tier is a fuel rating for brands of gas. Top Tier brands include Shell, BP, Exxon, and Costco among others
It’s a non-government sponsored standard. Top Tier is mostly marketing and branding and you pay to be listed.
It does mean you know you might be buying something that meets their definition.
How long before Wawa creates the Toppermost Tier standard that only they follow 🤪
Yeah idk you haven’t convinced me not to go to Costco. It might be just marketing fluff, in which case Costco is still cheaper than any BP or whatever so might as well get it
FYI, on the inside of your fuel door you’ll find AKI 93.
The engine will muster on lower octane fuel but, it’s a high compression engine that does best higher octane gasolines.
You won’t feel anything because the ECU will realize you’re not running good gas and pull timing to keep you from detonating your motor
Wish I could get 93, highest in California is 91. My tuner said CA gas is shit and recommended a gallon of e85 at fill ups.
Data logs look good
You can get 100 octane at a small number of gas stations in California, lots of them refer to it as “race gas”. Here’s a handy map someone else made of gas stations in CA that sell it: https://www.google.com/maps/d/viewer?mid=1yGUCmpCLUUPb4L_puE7bHQqXMlc
Apparently Ultra means something different there
Please use 93 in your car, your car will love you back. It’s not worth it to save few dollars on each refill.
Modern engines calibrate themselves if you use lower octance fuel so that they don’t knock, but still use 93 for your car’s best health.Very good advice!
If the manual says 91, put in 91. 93 won’t do anything for the health of the motor if it’s not designed for its use.
Using anything less than 91 in a BMW is a warcrime. Unless you live in California, because their 91 is closer to 89 anyways.
I wouldn’t put less than 91 on a b58 honestly. You might feel no difference but the car is definitely adjusting parameters in the background. It’s a performance oriented car I don’t know why you wouldn’t want it to run optimally
One of the cannonball runs I watched… I think it was with the AMG… they had a 93 octane tune on the car and when they started to get out west where the best available is 91 the car fucked up. Not sure why there isn’t 93… especially in California where it’s $5 a gallon.
This happened recently to Mat Armstrong taking his tuned RS6 to SEMA.
No issues up until he filled it with lower octane fuel than what the tune allowed. Caused pre detonation and blew the wall of one of the cylinders out into the cooling jacket. Hydrolocked the engine.
Expensive mistake.
These damn poverty states only having 91… like wtf, get with the program.
California gas is oxygenated to reduce emissions. It’s supposedly better for their air.
Used 98 in Europe in my previous petrol cars
93 only for ALL bmw
95
I’m in the UK 🇬🇧 so the octane numbers are different here, but I’m running my M340i LCI XDrive Touring on 99.
Petro Canada has Ultra 94 ever since they took over for Shell a long while back now. So I just continue to use it, but at Petro.
Bro put 87 in his M340i🤦♂️