Premium Gas

[MSchott]

You dont have 91 so you put 89 in your BMW instead of 93?? :lol::lol::lol:


:clap:

Sigh...

I'm pleased to see the high level of maturity in this post.

I don't have unlimited finds and I fill up at least weekly. The difference in price is significant where I live and I do have a budget. That said, I see no difference in performance or gas mileage. Frankly I think people are way too sensitive about this.

 

[Antero128]

We all have budgets. We arent on a Ferrari forum . I bought the GTI as a DD because that is what I can afford comfortably in this economy. You made the choice to buy a BMW. If you cannot afford the right gas for your car, you made the wrong choice. There is a reason why there are different grades of gas. Your engine is tuned by BMW to run the best at 91+ octane. Will you destroy your engine? No, probably not. Is it running like it should? No, it's not. Just like you said, your car is smart enough to figure out what gas you put in it and it is probably pulling timing. But $6?? Come on. Dont be silly.

Funny how I'm the immature one here.

 

[r56mcs]

If I was reaaaaaaaaaaaaaaaaaaally tight on spending money, I would use the cheapest gas. But I can afford premium gas so I will use what is recommended.

 

[Diego Armando]

I blame rap music for this thread.

 

[DD89]

This thread went a bit crazy, but as far as gas goes, I get 93 because that's most choices my gas stations have. Supreme or Ultimate it's called here and it costs around $3.29, which isn't too bad. When my brother bought his G35 he was paying onwards of $4.00 for 93.

 

[MSchott]

We all have budgets. We arent on a Ferrari forum . I bought the GTI as a DD because that is what I can afford comfortably in this economy. You made the choice to buy a BMW. If you cannot afford the right gas for your car, you made the wrong choice. There is a reason why there are different grades of gas. Your engine is tuned by BMW to run the best at 91+ octane. Will you destroy your engine? No, probably not. Is it running like it should? No, it's not. Just like you said, your car is smart enough to figure out what gas you put in it and it is probably pulling timing. But $6?? Come on. Dont be silly.

Funny how I'm the immature one here.

I'm not the one putting laughing smilies in my post. You also have no clue as to my financial situation do so please don't pass judgment on me. You are inferring things you have no clue about and frankly are none of your business.

 

[scottw86]

I blame rap music for this thread.

I blame the schools.

 

[daihard]

anything less than premium in a GTI doesn't make sense

You may want to tell that to VW.

All I've been trying to get at is that different people may have different, often their own, reasons for choosing what they do and don't , and that it is impossible to make an accurate judgment about them when you don't know their situations.

Their decisions may not make sense TO YOU. I have no problem with that. I just don't like it when you start telling people how wrong their decisions are without fully understanding what their situations, thought processes, etc., are.

I am not sure how else I can put it to make it clearer. Advice would be appreciated.

 

[MSchott]

You may want to tell that to VW.

All I've been trying to get at is that different people may have different, often their own, reasons for choosing what they do and don't , and that it is impossible to make an accurate judgment about them when you don't know their situations.

Their decisions may not make sense TO YOU. I have no problem with that. I just don't like it when you start telling people how wrong their decisions are without fully understanding what their situations, thought processes, etc., are.

I am not sure how else I can put it to make it clearer. Advice would be appreciated.

This is a very clear and very fair post. Thank you for your reasonable thoughts on this matter.

 

[Bender1]

30 cents
time 12 gallons
times 52 weeks

$187 (approximately) a year. $187 bucks it cheap insurance and cheap performance. If you spent the money to get a GTI you DO have the money to get the right gas. IF you really don't then you DIDN'T have the money to buy a GTI.

 

[daihard]

This is a very clear and very fair post. Thank you for your reasonable thoughts on this matter.

Thanks! I read your posts above and thought we'd be able to share this basic idea. Glad I was right.

 

[RatherBeInCabo]

You dont have 91 so you put 89 in your BMW instead of 93?? :lol::lol::lol:


:clap:

Sigh...

I also use 89 in my 528i as the manual clearly states minimum octane is 87, 91 preferred. Just can't seem to go for the 87 though. This subject also has been beat to death on the BMW forums.

 

[Tailwagger]

30 cents
time 12 gallons
times 52 weeks

$187 (approximately) a year. $187 bucks it cheap insurance and cheap performance.

Only a $.20 diff here today with 93 @ $2.99.

 

[daihard]

Maybe. If its -20 in Canada or 110 in Arizona? If you live at altitude? If you regularly load the car going up and down hills? And what do they consider an acceptable level of extra wear and tear? If you constantly run regular, is life expectancy of the motor cut by .15% or by 15%? All other things being equal, if the motor lasts an extra 5000 miles @ $.28/mile value you just made back $1400! Its just not clear to me that the min requirement is considered something you can do all the time or if they are simply saying that in a pinch occasionally you can do it.

Perhaps you are 100% right and there absolutely is no problem. But @ a cost differential of $257 over 36,000 miles ($.20 gallon, assuming both deliver 28MPG), I'll leave it to others to test the theory if they must. And I'd add that if there's a 1.5 MPG difference over the same period, you save a whopping $53. Drop any option from the build sheet and you'll save a ton more. Just doesn't seem at all a sane way to save money.

I am pretty sure your technical assessment above is spot on. However, it seems to apply to all gasoline engines, not just those of high-powered, performance cars that benefit from premium gas. Is that the case?

 

[jmblur1]

I am pretty sure your technical assessment above is spot on. However, it seems to apply to all gasoline engines, not just those of high-powered, performance cars that benefit from premium gas. Is that the case?

Cars not tuned for higher octane fuel will see zero benefit from running it - performance and mileage will be the same (or possibly slightly worse, as higher octane fuel is tougher to ignite).

Cars tuned for higher octane fuel, like the GTI, will see both performance and quite possibly mileage increases, as they can run a leaner mixture without the danger of misfiring. A leaner mixture means less fuel in the fuel/air mix (or more air). I'm pretty sure you can see why it's quite possible to end up with better mileage! This is also why some with tunes have seen highway mileage creep up a bit - the APR/GIAC/Etc. tunes assume you're ALWAYS using 91 or 93, so they push the envelope a little further towards leaner mixtures (generally by pumping more air in from the turbo). They also monkey around with the timing to take advantage of the mixture, as well as a number of other variables. Not quite as safe, but you get way more power out of it and slightly better economy to boot.

As for the "why", basically, a leaner mixture is more prone to preignition/detonation, but it's also a more potent mixture. Running rich is safer, but causes more pollution (soot, mainly) and produces less power.