[Elk]

Originally Posted by mhdelarosa

My understanding is that BP is not recognized as "top tier" gasoline due to their fuel not having the necessary quantity/quality of detergents present to be categorized as "top tier." Hence BP Arco markets their brand as "straight up gas."

Do you have a source for this? Who is the recognizer of "top tier?"

Arco is merely a highly competitive, high volume, low service (such as no credit cards) retailer. Their "straight up" phrase is merely marketing.

[mhdelarosa]

http://www.toptiergas.com/retailers.html

[westcory]

Originally Posted by bosz

Im afraid I have to agree with this. When I went to the BMW event, they had a BMW engineer explain all the technicals to us and i asked him specifically about the "minimum 89 Octane". And the above is exactly what he said, word for word. The whole higher octane thing is just anoth hype to get consumers scared into buying the more expensive fuel. He also said 94 octane is just a complete waste unless the engine is designed for it bla bla bla.

He said in the F30 the knock sensor will only come on if you use lower than minimum octane of 89.

Just google this octane debate and you'll be shocked at how useless higher octanes are in most cases (some can even damage ur engine)

As another engineer, do the math. Look at the Otto cyle and do the math. Look up the correct values for gasoline/ air mixture at STP. You will only see issues in places like Phoenix that get very hot in the summer.

[Elk]

Originally Posted by mhdelarosa

http://www.toptiergas.com/retailers.html

Vague and odd site.

If BMW actually buys into this, as claimed, it is indeed odd that BP is not included in the blessed sources of petrol.

[FSociety]

Originally Posted by mhdelarosa

http://www.toptiergas.com/retailers.html

I second this!

[David1]

Originally Posted by Ahmadhosmanbmw335i

The higher the octane rating the cleaner your engine will be and you'll get better Mpgs and you'll feel the difference when you press the gas. I would suggest filling up at gas stations that have invigorate such as shell or bp they have the best gas and invigorate helps clean your engine and prevent build up.

Fuel cleaner additives can not prevent build up on the intake valves on DI motors.

[E90Fleet]

Incase anyone was wondering, the factory here puts BP in the F30.
Octane 95 RON


Remember USA shows PON = (RON+MON/2) on the pumps, whereas here and in Europe we show RON.
95 RON should be around US PON 92

[hollandog]

I fill 93 all the way with my G37.

The difference between 91 and 93 is $0.02 per gallon.
I don't see a reason why I should choose 91 over 93.

[sleedawg]

Originally Posted by mhdelarosa

http://www.toptiergas.com/retailers.html

Don't always trust what you read on the internet. Especially forums.

Hmmm... So, who owns the TopTierGas.com site? General Motors.
Who do they link to? 76 Gasoline.
Who owns the patents for this "Top Tier" formula? Unocal 76.
http://www.google.com/patents/US20040242436

-----

Unless you're constantly pushing your car with full throttle, in harsh atmospheric conditions (high altitude or temperatures) and always use max boost you probably don't need the 91+ but it's insurance against pinging (aka knock). As it's been implied by others... the factory ECU's fuel map is programmed for the different fuel grades within a range (my guess 87-94 octane) and will adjust fuel, timing and boost accordingly. Considering how much extra safety buffer BMW puts in their fuel maps, you should be fine whichever side of this argument you want to be on.

[funkerpoke]

Originally Posted by Ahmadhosmanbmw335i

The higher the octane rating the cleaner your engine will be and you'll get better Mpgs and you'll feel the difference when you press the gas. I would suggest filling up at gas stations that have invigorate such as shell or bp they have the best gas and invigorate helps clean your engine and prevent build up.

Sorry, but the first part of your statement is incorrect. Higher octane rating does not relate to cleaner engines. All grades have same detergent. I know oil companies advertisements are misleading and they want people to believe this but it is not the case. I did work for the largest for 31 years.

[dr.omid.fahim]

ive used 94 & 99 in my f30 with out any noticeable differance but on my 520 i non turbo engine 99 makes a whole word more torque & quite noticeable acceleration differancei ve never used below 93 even thogh 98 to 99 is 25 % more expensive here

[NightWriter]

Originally Posted by Bmwny2015

The higher the octane rating the cleaner your engine will be and you'll get better Mpgs and you'll feel the difference when you press the gas. I would suggest filling up at gas stations that have invigorate such as shell or bp they have the best gas and invigorate helps clean your engine and prevent build up.

Please stop spreading this misinformation. Higher octane is completely unrelated to fuel quality or its added detergents. And I don't think I've ever seen proof that lower octane gas reduces fuel efficiency.

[rking117]

Originally Posted by CE750Jockey

So let's go with this: Can you provide us with the empirical data to substantiate your claim of increased performance with higher octane gas in a 2012 N20 or N55 engine? Yes or no?

Are you serious? simply put if you fill up your tank with 89 octane and drive until it is empty noting the mileage and then noting the gallons to fill up and do a little math you can get your MPG. RIGHT? Do the same with 91/93 and compare. There IS a noticeable difference between the two in MPG increase by octane so your wanting to bring out the white coats isnt needed. that is whats wrong with the world today. everyone wants to make things too complicated.

[casualDIYer]

I'm not sure why 'grade' is used to describe octane. The quality of the fuel is the same. The octane differs. I believe gasoline starts at 64 octane then additives are added for various reasons to adjust it. High octane means slower burning and is, generally, ideal for high compression engines typical in turbo equipped cars.

For me my fuel decision has never been about octane but ethanol content. The biggest problem with ethanol? THE BIGGEST? Its mandated in Canada. Canadians can't even escape the US to free ourselves of this head up the a$$ decision made during an oil market much different than today's reality because it seems this bad decision is pervasive across the border. Europe and the UK are probably in the same boat.

It is possible to buy eth free gas though. Shell 91 doesn't have it but it is pumped with the same hose that pump eth infused gas so a bit does make it in. Oddly many say that higher octane gas 'cleans' your engine. The reality is ethanol is a better cleaner than gasoline. Want to clean your engine? Get gas with the MOST ethanol, not the least.

Want to know why 'high' octane gas gets better mileage? Its has less ethanol. Ethanol = gets you plastered at parties Gasoline = Makes cars go

[rking117]

Originally Posted by NightWriter

Please stop spreading this misinformation. Higher octane is completely unrelated to fuel quality or its added detergents. And I don't think I've ever seen proof that lower octane gas reduces fuel efficiency.

If that is the case then top fuel dragsters would be burning 1.99 per gallon gas instead of 5.00 per gallon racing fuel. Come on man denying the issue without doing your home work is not cool.

The science behind octane.

the higher he octane the more combustible the fuel. this gives two derivatives. More HP which means under normal loads means more mileage output. The math behind this is simple. I mean come on reallY? Next i will hear that you believe we didnt go to the moon right? Wait dont answer that I dont want to have any further of a negative opinion at this point.

Im totally shocked by all of this speculation.

[rking117]

Originally Posted by menncars

For me my fuel decision has never been about octane but ethanol content.

ditto. for sure.

[Billfitz]

Originally Posted by NightWriter

Please stop spreading this misinformation. Higher octane is completely unrelated to fuel quality or its added detergents. And I don't think I've ever seen proof that lower octane gas reduces fuel efficiency.

+1. Very few consumers even know what octane is, and will pay for higher octane fuel based purely on the notion that more expensive means better. It doesn't. Higher octane fuel is more resistant to pre-ignition, meaning that it's not more volatile, it's less volatile. Where energy content is concerned there's no difference between different grades of gasoline.

The circumstance where lower octane fuel will deliver less mileage is when the compression ratio and/or atmospheric boost causes lower octane fuel to pre-ignite, and computer control retards the spark timing to eliminate it. That will reduce the engine efficiency. Typical stock passenger car engines, BMW included, don't utilize high enough compression ratios or boost pressures for this to be an issue.

Recommended minimum octane ratings tend to be more of a marketing decision than an engineering requirement. Since the average consumer thinks that higher octane is necessary for higher performance a minimum octane recommendation more often than not is made so that the consumer will associate that recommendation with higher performance. If BMW, for instance, said that 87 octane was perfectly fine they might lose sales to the uninformed who would think that a car that supposedly required 91 octane would perform better. Discussions like this one indicate that the marketeers are right.

[NightWriter]

Originally Posted by rking117

If that is the case then top fuel dragsters would be burning 1.99 per gallon gas instead of 5.00 per gallon racing fuel. Come on man denying the issue without doing your home work is not cool.

I'm not sure what you're arguing here. Yes, racing engines designed/tuned for higher octane levels can indeed produce more power as a result. I didn't say anything to the contrary. I was simply trying to dispel the oft-cited myth that lower octane gas is of lower "quality" or necessarily impedes fuel efficiency.

For the record, I suggest following the recommendations of the engineers who designed the engine, namely that which appears on the sticker and in the owner's manual.

[adhrp]

Originally Posted by rking117

simply put if you fill up your tank with 89 octane and drive until it is empty noting the mileage and then noting the gallons to fill up and do a little math you can get your MPG. RIGHT? Do the same with 91/93 and compare. There IS a noticeable difference between the two in MPG increase by octane

Wow...looks like a really old thread has been resurrected.

Without wanting to get into the argument about top-tier fuel, detergent, etc, I can confirm that the above is true.

When I first got my car I had seen some threads arguing about 89 vs 91 octane so out of curiosity I did a few tests over a 2000 mile road trip that I took shortly after purchase to get some empirical data. I was mainly looking for performance differences between the two, but what I noticed was that there was a slight mileage drop at 89 compared to 91. I don't remember the exact numbers (they should be somewhere here or on Bimmerfest in one of my old posts). And when I did the math it turned out that while 89 was cheaper, the loss in mpg actually nullified those savings. Since then, I've been using only 91 (that's the top we get here) or above.

[Pyewacket69]

Let's add in the debate of RFTs .vs GFTs here and really get this thread going...

[NightWriter]

Originally Posted by adhrp

Out of curiosity I did a few tests over a 2000 mile road trip that I took shortly after purchase to get some empirical data. I was mainly looking for performance differences between the two, but what I noticed was that there was a slight mileage drop at 89 compared to 91. I don't remember the exact numbers (they should be somewhere here or on Bimmerfest in one of my old posts). And when I did the math it turned out that while 89 was cheaper, the loss in mpg actually nullified those savings. Since then, I've been using only 91 (that's the top we get here) or above.

Empirical data FTW

[casualDIYer]

Originally Posted by rking117

If that is the case then top fuel dragsters would be burning 1.99 per gallon gas instead of 5.00 per gallon racing fuel. Come on man denying the issue without doing your home work is not cool.

....

No they would not or they'd lose every race they entered.

Dragsters use nitromethane, a fuel with LOWER energy density than gasoline but to burn a kilogram of gasoline you need almost 15 kgs of air. To burn a kilogram of 'nitrometh' less than 2kg of air are required. Despite the difference in energy the dragster will burn about 8 times as much nitro as gasoline.

That's pretty crappy mileage but I have a feeling that dragster teams aren't too concerned about mileage.