So the consumer is supposed to have a list handy of “inappropriate fuels”?
No way I see a warranty claim being denied using 87 vs. 93 premium. How are they going to prove the use of lower octane “inappropriate fuels?” They get reimbursed by the manufacturer on warranty work (albeit at lower rates).
I’ve had the opposite of Audi dealers wanting to do (non mfg required) carbon cleaning with each and every Audicare visit.
This reminds me of the last time I was getting my car serviced and I overheard one of the techs explaining to a woman how they found that someone had put diesel instead of unleaded into her tank and they would have to drain and flush the entire system… 
Now there’s a mistake you definitely don’t want to make.
But fuel quality in terms of detergents and ethanol content is totally different than is octane rating, no? I thought part of the reason why BMW (and presumably Audi) makes mention of detergents is b/c the carbon buildup from the direct ignition was b/c some US chains lack the detergents needed to keep the injectors (or whatever parts) clean?
By seeing what fuel is in the car. And the car records almost everything. So if there is a history of knock sensors having to retune the engine for lower quality fuel, it will be recorded. If 93 is required and you are putting in 87, then expect the manufacturer not to pay for a warranty claim since they can argue the defect isn’t due to their workmanship. No difference IMO than waiting until 20,000 miles for an oil change if the manufacturer required it to be every 10,000 miles.
Correct, but they put the caveat in there to use the recommended fuel grade. The statements is vague enough where it is really easy for a warranty company to claim that unrecommended fuel was used and deny a claim. All I am saying is that saving $1000-$2000 in gas over 3 years isn’t worth the headache of rebuilding an engine from your own pocket.
I am driving PHEV (530e) with close to 50MPG. Honestly speaking, I got that car to cut my gas bill (from V8 GX460) and not for the badge or performance (thanks to leasehackr 
). I initially drove 5-10K on 87 then ended up switching to 93 octane but I can’t tell if it improve performance at all. It still takes off in same spiffy way … but my gas bill went up by 25%… that led me to ponder if its even worth paying gas premium for car that I will not drive for more than 20K mi …
Unless the check engine light went off, you are fine. Depends on specific model to be honest. My mom used to put regular in her 330 and my sister puts regular in her 330 now, my dad used to put premium in his old 5 and puts 91 or higher in the M models. All depends on engine and manufactures recommendations
An engine retarding timing/reducing performance due to lower octane fuel isn’t going to trigger a CEL.
It did on the 5 series my dad had from 2013-2016, the first time he filled the tank he accidentally put regular and the light went off as soon as he turned the car on and left
Did he forget to put the cap back on? That’s about the only thing that’s going to cause that immediate of an issue, unless it was an incredibly hot day, he had the car overloaded, and he floored it going up a hill causing lots and lots of knocking.
We are in NJ so the gas attendants always close the cap, I’m telling you, the only reason he put premium after that was because the light would go off if he didn’t.
HA HAHA HAHAHAHA. You funny guy, you know that? 
One time I was in South Jersey. It was 10pm at night and I needed a gallon or two to get from where I was to my friends used car lot. I handed the attendant $10 and went to use the bathroom, came out and the pump was at $5 and stopped.
I was so tired I cussed him off and left. Stupid Subaru. If I hadn’t sold them a car that day I would not have taken that lease return…
Two lessons, don’t do lease returns, and don’t give gas attendants cash. Got dinner out of it from my friend so all’s well.
I don’t remember last time I used cash at a gas station, I mean generally try to avoid having cash. I only use Costco (if conveniently on the way) and Exxon because of the card that makes credit same as cash at the pump automatically, plus gives like 6 cents off a gallon or something, but mainly it’s the credit same price as cash.
i wouldnt bother putting premium in a leased car if you have no intention of buying it out in the end
Using premium is primarily about getting the performance out of the engine that you paid for. I don’t personally see a difference between buying or leasing in that regard.
It should be based on whether it’s required or recommended, not if you’re going to buy out or not.
This. Any modern engine would be able to adjust injection angle and prevent detonation. But performance would suffer.
I guess you shouldn’t detail or wash it either, cause it’s just going back to the dealer in three years!
Leasing a car that requires premium fuel (which are almost all luxury or sports cars), and then trying to save a few hundred bucks is the very definition of pennywise/poundfoolish.
And I speak as someone who has put regular into premium cars…if you don’t notice it, don’t waste your money on that type of car.
Usually just pull back timing.
