[playndirty]

What about comparing Costco gas vs chevron or shell or 76? Much difference?

[bnekic]

Originally Posted by dyzfnctional

What about comparing Costco gas vs chevron or shell or 76? Much difference?

Gasoline in it's base form is all the same. The difference between brands is the amount and formulation of cleaning agents that they add to the gas.

[jdong]

Originally Posted by bnekic

Gasoline in it's base form is all the same. The difference between brands is the amount and formulation of cleaning agents that they add to the gas.

FWIW Costco now runs a bit of an ad campaign at their pumps claiming that they use 5x more detergent than the EPA requirement, which sounds similar to the Top Tier claims.

For me I mainly don't use them because of the long lines at my local Costco. I know others who have run their German cars off Costco gas with no issues.

[Elk]

Originally Posted by bnekic

Haha wow, pure ignorance.

We have addressed this "argument" previously. You claim forced induction cars absolutely require high octane.

Simply put, this is false.

BMW is smart enough not to recommend AKI 87 if use of AKI 91 is required. To claim the recommended minimum 87 octane will result in engine damage is specious - and contrary to the holy book, a/k/a the manual.

The more sophisticated technology of direct injection, coupled with other advances, allows engineering turbo engines specifically for 87 octane. Consider the modest Chevrolet Cruze: 1.4L turbocharged, direct injection - 87 octane is specified for this car. Are you admitting GM engineering can readily accomplish something in an inexpensive car that BMW cannot even while charging $25,000+ more?

There may well be a small decrease in power with lower octane. Consider this dyno test of 87 and 91 octane by Edmunds on a 2010 Volkswagen GTI, another forced injection engine designed to run on 87 or higher octane.

Conclusion: "In summary, 87 octane hasn't had a tremendous effect on our GTI's ability to hustle." As to any alleged danger to the engine:
"Note that modern engine controllers are quite adept at monitoring knock activity and adjusting accordingly. I heard not a single ping when running the snot out of this car on the dyno in either test." Clicky

Time to join the current century and its wonderful technologies. BTW, have you seen the really neat, small personal telephones you can hold in your hand and carry anywhere? They are amazing.

[bnekic]

That's great and all but once you starting tuning premium in mandatory. Plus you've spent a bunch of money on a BMW why are you even discussing what fuel to put in? Are you that cheap that you can't use premium fuel and get the best performance out of your vehicle?

Your the guy that would use 87 octane constantly in your Bugatti Veyron because the manual said you could use it if nothing else was available.

[jdong]

Originally Posted by bnekic

That's great and all but once you starting tuning premium in mandatory. Plus you've spent a bunch of money on a BMW why are you even discussing what fuel to put in? Are you that cheap that you can't use premium fuel and get the best performance out of your vehicle?

The tuning part may or may not be true depending on the tune. When I got the STaSIS ECU remap on my 2.0T A4, they specifically told me that I can still use 87 if I wanted, and the ECU will appropriately compensate.

Now as far as why everyone is arguing over a 3 or 4 dollar a tank difference, no idea. I typically use 91 just because it is what is recommended. But on my A4 I've done a 5000 mile experiment with just 87 and didn't really notice performance or fuel economy differences, and I track all of my fill ups over the 35k miles I had the car.

[RPM90]

Caution: This post is not directed at any one particular poster.

There's information based on science, physics, mechanics...., and then there's 'information' based on anecdote and feelings, and a want to dissect what "recommended" means.

There is plenty of "information" posted in these fuel threads that will make anyone with an opinion on octane feel good about their opinion.

[Mak135i]

Originally Posted by RPM90

Caution: This post is not directed at any one particular poster.

There's information based on science, physics, mechanics...., and then there's 'information' based on anecdote and feelings, and a want to dissect what "recommended" means.

There is plenty of "information" posted in these fuel threads that will make anyone with an opinion on octane feel good about their opinion.

[sean10mm]

Originally Posted by Elk

BMW is smart enough not to recommend AKI 87 if use of AKI 91 is required. To claim the recommended minimum 87 octane will result in engine damage is specious - and contrary to the holy book, a/k/a the manual.

What? The current F30 manual says AKI 89 is the minimum fuel grade. It clearly tells you not to go below 89.



You're actively spreading disinformation here.

[bnekic]

^ oh no, Elk is the end all be all.

[Elk]

Originally Posted by sean10mm

What? The current F30 manual says AKI 89 is the minimum fuel grade. It clearly tells you not to go below 89.
You're actively spreading disinformation here.

Sorry, Sean. You are absolutely correct, it is non-premium AKI 89 which BMW recommends, not AKI 87. The reference to AKI 87 in this post was a typo in the context of BMW engines. BMW directly states mid-grade AKI 89 is perfectly fine, premium is not required. (I also previously addressed your reference to the manual in post #85 of this thread.)

The rest of my post addresses that many modern forced induction engines do not require premium and, in fact, may even specify AKI 87. At some point, BMW may also be able to offer forced induction engines which can run on all fuels while also taking advantage of increased octane if available - as does the the Audi 2.0T.

The discussion has nothing to do with the trivial price differential between the fuels. If price is your concern, run AKI 89 with impunity and forget about it. On the other hand, run AKI 91 if your emotions dictate you must. Just do not fool yourself into believing AKI 91 is required or necessary.

Your choice.

Summary: Forced induction does not require premium fuel. There are turbocharged engines which specify AKI 87. BMW engines are perfectly happy on both AKI 89 and AKI 91, but unfortunately cannot handle AKI 87.

[jdong]

Note also that the consequence listed is "impair engine performance"' not "it'll explode" or "engine damage".

[Mak135i]

Higher octane will yield higher performance in most conditions... All the tuners' dynographs that I have seen compare engine output with 91 and 93 octane fuel (here in US) show that 93 helps the engine achieve higher HP rating. If you use racing fuel (unleaded 100 or higher), the output will be even higher.

Of course the manual clearly states 91 is recommended and the minimum is 89.
Sorry to add to this thread, but it seems the "savings" (if that is the motivation for using lower octane fuel) would be very small compared to the possible benefits of using the 92 or 93 (about 15 cents/gallon).

[redbullto]

My manual says 89 recommended. But it is not required. That is why I have used 87 on this and my previous cars. There is no discernible difference in performance or gas mileage. For all the doubters check this out http://www.cbc.ca/marketplace/episod...mpfiction.html

Here in Canada the cost between grades is not trivial but even it wasn't you gotta be an idiot to pour money down the drain for no good reason no matter what car you buy.

[Cyberdemon]

Originally Posted by redbullto

My manual says 89 recommended. But it is not required. That is why I have used 87 on this and my previous cars. There is no discernible difference in performance or gas mileage. For all the doubters check this out http://www.cbc.ca/marketplace/episod...mpfiction.html

Here in Canada the cost between grades is not trivial but even it wasn't you gotta be an idiot to pour money down the drain for no good reason no matter what car you buy.

This post hurts my brain.

A car tuned for 87 will receive no benefit by running premium gas, which is what that article is about. That is true, which is all that expose proves. That's why dumping premium in your Chevy Cruze doesn't matter and makes no sense.

A turbocharged car tuned to run on premium will automatically reduce performance courtesy of the knock sensor to avoid detonation, this is nothing new. The same way a high boost race engine that is tuned to run on 110 will not make the same power on pump gas. It will still run just fine, because the engine has enough safeguards to ensure that the crappy gas doesn't hurt it. It's already well known that here in the states, certain states like California already have gas that is crap compared to other states.

But if you actually believe your car is running as well on 87 as it would on 91 I'd invite you to do the same dyno test if you want to put your money where your mouth is.

Also financially speaking, if you look at the delta in cost between premium/regular (here in NY with our high gas prices the delta is typically $.25-.30 between 87/91) you're talking about less than $5 per fillup. At that rate I'd advise you to consider if you ever have paid money for a cup of coffee or bottle of water that maybe you should reconsider those decisions also.

[Tsuvoi]

Originally Posted by Cyberdemon

This post hurts my brain.

A car tuned for 87 will receive no benefit by running premium gas, which is what that article is about. That is true, which is all that expose proves. That's why dumping premium in your Chevy Cruze doesn't matter and makes no sense.

A turbocharged car tuned to run on premium will automatically reduce performance courtesy of the knock sensor to avoid detonation, this is nothing new. The same way a high boost race engine that is tuned to run on 110 will not make the same power on pump gas. It will still run just fine, because the engine has enough safeguards to ensure that the crappy gas doesn't hurt it. It's already well known that here in the states, certain states like California already have gas that is crap compared to other states.

But if you actually believe your car is running as well on 87 as it would on 91 I'd invite you to do the same dyno test if you want to put your money where your mouth is.

Also financially speaking, if you look at the delta in cost between premium/regular (here in NY with our high gas prices the delta is typically $.25-.30 between 87/91) you're talking about less than $5 per fillup. At that rate I'd advise you to consider if you ever have paid money for a cup of coffee or bottle of water that maybe you should reconsider those decisions also.

Agreed, you paid 50k for a fancy car that stipulates premium gas and you try to save 5 bucks at the pump for a grand total of $200 bucks in a year or something? Sometimes you need to take a step back and look at the big picture.

[redbullto]

Nevertheless, it is not required. I have not noticed any difference and the science and the FTA confirm it. If it makes you feel better than buy it but one should accept the evidence. And here in Canada its a $10-$12 per tank premium. I'd rather buy the overpriced coffee with that cash. At least I can actually taste it.

[S-Dot]

Originally Posted by redbullto

Nevertheless, it is not required. I have not noticed any difference and the science and the FTA confirm it. If it makes you feel better than buy it but one should accept the evidence. And here in Canada its a $10-$12 per tank premium. I'd rather buy the overpriced coffee with that cash. At least I can actually taste it.

*...then buy it...

The "science" most definitely does not back what you are promoting. As has been said already about eight million times in this thread, additional octane will not help a vehicle that is not tuned to take advantage of it.

Your car is so tuned, as are many others. It gets both better performance and better mileage with premium fuel because it is capable of advancing the ignition timing and extracting more power per ignition cycle.

If you don't wish to believe that fact based upon what you've "noticed" or misinterpretations of internet reports, that's up to you, but you are quite incorrect in your thesis, as has been repeated in this thread ad nauseum.

[jdong]

Originally Posted by redbullto

Nevertheless, it is not required. I have not noticed any difference and the science and the FTA confirm it. If it makes you feel better than buy it but one should accept the evidence. And here in Canada its a $10-$12 per tank premium. I'd rather buy the overpriced coffee with that cash. At least I can actually taste it.

Does "Do not use any gasoline below the minimum rating" translate to "not required" in Canadian English?

[Cyberdemon]

Originally Posted by redbullto

Nevertheless, it is not required. I have not noticed any difference and the science and the FTA confirm it. If it makes you feel better than buy it but one should accept the evidence. And here in Canada its a $10-$12 per tank premium. I'd rather buy the overpriced coffee with that cash. At least I can actually taste it.

You may want to get an engineering degree before you talk about the science.

A car rated for 87 octane makes no difference.

A turbocharged engine rated for 91 octane makes a difference:

http://blogs.insideline.com/roadtest...its-power.html

A GTI falls into the category of turbo engine rated for premium.

There is a few HP fall off at peak, with about 5% falloff elsewhere in the powerband.

Even on an NA engine there are deltas.

http://9glancers.com/index.php?topic=9117.0

So if your response is "well I can live without a few HP to save $10" then go for it, that's your prerogative. But don't try to explain to a board of enthusiasts who will spend $300 on an air filter and piece of pipe to gain 5whp that there is no difference, because it's simply wrong.

[Munit]

People claiming 89 makes no real difference are not taking into account real world situations. Theoretically the n55 probably makes really close hp on 89 or 91 under really perfect conditions with cool dry air, limited WOT runs, no uphill etc.

But the real world is not like this. Do 2 or 3 WOT runs in a 80 degree summer day and the car is pulling timing like crazy even with 91 and thus is not making near peak power, let alone with 89 which would just be pulling even more timing and making less power.

Atleast with the M cars they also achieve max horsepower with 95 octane given the timing targets are not able to be achieved with 93 or lower octane because knock prevents it so it cuts timing. With 95 the m3 can hit its OEM timing max target because it resists knock up that high.

So on paper there is no difference maybe but one real world drive and that is all out the window

[azzurro]

Originally Posted by jdong

FWIW Costco now runs a bit of an ad campaign at their pumps claiming that they use 5x more detergent than the EPA requirement, which sounds similar to the Top Tier claims.

For me I mainly don't use them because of the long lines at my local Costco. I know others who have run their German cars off Costco gas with no issues.

I've never bought gas at Cost Co nor ever will. I don't wait. It's amazing what people will do to save a couple of bucks. My time is worth way more than this. Same reason my car will only get 91 octane which is the highest available in California. If we had 92 or 93, I'd use that.