[BEAR-AvHistory]

Originally Posted by blankito

Are you saying all the CHIP tuning are based on nothing? No matter the CHIP you use on your car (either Unitronic on a VW, JB4, MPPK), they all take into account the octane level in the gas to achieve specific performance and use dyno data to confirm their tuning.

Your stock BMW car is simply tuned to be used with 91 octane but is "okay" using 89. Another CHIP might be tuned for 93 octane, etc etc.

Another good example is the JB4 on map 5, which will detect the octane level in the gas and change the performance accordingly.

I completely agree that octane level means nothing on a Toyota Corolla that is designed to run over 87 octane. If you put 91 or 93, it won't help anything. However, putting lower than what the car is designed for, that's another story...

Point he is ignoring or is unaware of is all brands tune for the best power & EPA numbers they can get. Most never tell you what grade fuel you need to get that.

FORD has been stepping up to the plate at least with Mustang with an * on the HP number.

* obtained on 93 octane.

[natesi]

I was on a road trip with my friend and he said he would gas up my car since I was driving. I went into the mini-mart to take a wiz and after I got out the car was all filled up. It then occurred to me to ask what grade he put in -- and he said 87!! And it was a whole tank! I thought there would be knocking, etc. But to be honest, the car drove fine and I never even noticed a difference.

[Rox335i]

I always fill my cars with 91.

[eluded]

use 87 octane. The ecu will compensate.

[KOWTOWN]

You're saving like $2.50 a fill up, what is the point of risking it for?

[tuco44]

Originally Posted by eluded

use 87 octane. The ecu will compensate.

Then why buy a performance vehicle?

[Gen13 F36]

Wanna save money on gas, buy electric or fuel cell car.

[upsidedownfunnel]

Originally Posted by 3A53

Well if the power department is your main concern no 3-series comes close to other cars you can drive off the lot for the same price.

For me I'd just rather save the money. I save about $1000/yr doing my own basic maintenance and brakes and another $200/yr using 89 instead of 91. Those savings basically go into index funds and projecting forward 40 years to age 65 using the 1928-2017 inflation-adjusted CAGR that would put the cumulative car savings at a bit above the current median American net worth at 65. Still driving the same cars the same miles.

My point is that everyone is so ready to spend 'only a couple dollars a day' on this and that and at the end of the day more than half don't save 'a couple dollars a day'

Gotta draw the line somewhere. My car is still much faster than a 320i on 91.

You may think you're saving $200/year, but you're also reducing your gas mileage a little bit. I do my own work and don't like wasting money, but I never hesitate to, or question my desire to use premium gasoline. I would pay more for 93, in fact. There's also a small chance that using a gasoline with a higher anti-knock index will prolong engine life. Saving you even more money in the case of some type of failure.

[upsidedownfunnel]

Originally Posted by IanW555

Would be great if someone did some dyno testing on the different octanes available. Here in the UK the lowest is 95 octane, which I use, I often wonder whether the ECU would adjust up to make the most of the 98 octane available?

Europe uses RON. U.S. uses AKI. 95 RON is equivalent to 91 AKI. So while Europe does have slightly higher octane ratings, it's not as high as it seems just by comparing the numbers.

[chiefneil]

Originally Posted by tuco44

Then why buy a performance vehicle?

He didn’t, he bought a 3-series.

[eluded]

Originally Posted by tuco44

Then why buy a performance vehicle?

I often wonder that when I see these threads

[Kafkaesque328]

Originally Posted by F30guy

Are there any issues with doing this long term? Any idea on how much HP is lost running 89 rather than 91? (91 is the highest here in CA)

Other than the single tank of gas that your cheap ass will be able to buy with all the money you saved over the course of the year running a lower grade gas in your $50k car? Issues besides you getting sub par performance and fuel economy due to timing changes, thus negating your savings? No, no issues with this long term at all

[blankito]

Originally Posted by Kafkaesque328

Other than the single tank of gas that your cheap ass will be able to buy with all the money you saved over the course of the year running a lower grade gas in your $50k car? Issues besides you getting sub par performance and fuel economy due to timing changes, thus negating your savings? No, no issues with this long term at all

:

I think it perfectly sums up the whole conversation

[Gen13 F36]

Its ok....its just a least.....lol

[F30guy]

Originally Posted by chiefneil

He didn’t, he bought a 3-series.

Its a 430i convertible and yes, its not a performance vehicle. 248HP isn't much, I just didn't see it being worth it to buy a 440i with the extra cost of the vehicle and the 15k miles I drive a year.

[Cyanfall]

Originally Posted by blankito

I just don't understand people who buy expensive cars, often spend thousands on accessories and mods but get cheap on gas rating...

Honestly, I would never go lower than 89 since that's what is required. They say they recommend 91 so I put 91... Since I got a JB4 I always use 94 when available and 91 when there is nothing else

I do not have any numbers regarding power or mileage, but on most cars I had, I could feel the car ran smoother with the recommenced grade. Also, unless you drive 3000 miles per month, the difference between 89 and 91 will be only a few dollars per month so why take a chance?

but 430 is not an expensive car. f3x are not 7 series, m, or porsche. F3x are simply normal people's car.

[BEAR-AvHistory]

Originally Posted by tuco44

I am in the camp that runs the octane rated gas that BMW recommends for my particular car. I use 91 and 94 (Chevron) exclusively.

This topic keeps coming up about every 2 months or so, and there are always those who run lesser octane rated gas than is recommended. And I always wonder why you own a vehicle with recommended 91, then run 89 or even 87. I just don't get it......I have to believe that BMW recommends 91 for a reason.......

Its the perceived $240 or so annual economic savings by the buyer. Seems like a majority of the 87 users have 4 cylinder cars. Cheaper version of the car & cheaper gas to run it. matched set.

Agree this conversation constantly comes up & changes nobody's mind.

[Gen13 F36]

I still don't understand this....lol.

Buy electric car and you don't need to worry about what grade gas you put in your car🤣

[revone]

Originally Posted by upsidedownfunnel

Europe uses RON. U.S. uses AKI. 95 RON is equivalent to 91 AKI. So while Europe does have slightly higher octane ratings, it's not as high as it seems just by comparing the numbers.

Thanks for this - I just learned something new, I was thinking that you 'mercins had really crappy fuel, now I know you just rate it differently. Quick trip to wikipedia gave me the rest of the details too.

[Fuller]

When I bought my current car, it had obviously been filled by the dealer with whatever was the cheapest gas available. When I subsequently filled it with premium, I began getting noticeably better fuel economy, and the car definitely seemed to have a more "eager" throttle response. I've even noticed issues (like transient check engine light) when using various different brands, so I make every effort to fill mine only with Mobil premium now.

Filling a premium or performance car with the cheapest fuel is sort of like using generic coffee beans in a $1000 espresso machine, or wearing a custom tailored suit with dull, bargain basement shoes.

[TF3090]

Saving this thread so I know who to never buy a used BMW from

[Savageenterprise]

Originally Posted by tuco44

Then why buy a performance vehicle?

+1