^^Now THAT is a well-versed explanation from an obviously experienced motor head. Thanks 33EJB

 

The fun part was all the on-road "testing" you had to do. A great excuse to drive around with your buddies. Usually had to do a burnout or two, just to make sure everything was working OK. Then back to the garage for a beer, and telling lies about your last time at the drag strip.

 

The knocking sound you hear is not the pistons banging into something...that can't happen...the knock is the gas igniting and exploding when it shouldn't. You will not hurt the engine with today's electronics...and in the Mini manual it says you can use a octane lower than 91 but for the best performance...power the engine needs 91. So you are wrong about Mini having an issue when you bring it in for service. In Florida we have 93 and that is what I use but I would have zero issues if I had to use 87 or 89.

 

Knock is not an all or nothing thing. It can run from only barely detectible on a cylinder pressure trace to very audible and violent. A good knock detection system will detect incipent knock way before it can be heard and before the forces on the piston, rod, bearings are significantly stressed. BMW actually runs some durability testing that includes the engine running at iincipent knock. I am not saying that running at slight knock is good for your engine, but probably will not really effect the life of your short-block. I would be more concerned with the life of the catalyst and exhaust manifold fro mhigh temps due to retarded timing.

I am pretty sure that the knock detection system does not store any codes.


Dave

 

Out here in Chi-town, 93 is what you mostly find for premium. I know spending the extra 15-20 cents/gallon hurts some, but it's got to be at the bottom of the list of ownership costs. In any event, you can save a little by mixing the 93 with 89 at some 1/2 tank fill-ups.

 

As I said earlier, the MC engine has an 11.1:1 compression ratio.

A friend was telling me this story earlier today. He didn't recall the octane number either, but said that teenagers would take the family car, remove the air cleaner, fill it with 260, and drag race on Saturday nights. Reminds me of American Grafiti.

IIRC, the real fun was trying to balance dual solex carbs. Fortunately, I was spared that joy. My '57 Alfa just had a single two-barrel carb. If the car sat for a few days, the float bowl would drain and you had to start it by having someone crank it while you used a pump oil can to spray gas into the carb. Then replace the air cleaner and go.

I like the modern conveniences.

 

you are guessing incorrectly.

I had knocking listed on my service printout. (caused by advanced timing from unichip - not the gas).

Go ahead and run whatever y'all want. I care enough about my car to use the best I can get. My MINI's engine is worth a lot more than 20 cents per gallon savings.

If you are too poor to buy premium you are too poor to buy a MINI.

 

It is difficult to find anything higher than AKI 91 in California.

 

Same gas here.

People need to remember that engineers plan for this. They understand that people will be cheap, ignorant, or just won't care and will throw lower octane fuel in their cars. Because of this, they put multiple safe guards in place to make sure that they don't have a high volume of warranty claims. There is no reason you can't run lower octane gas in your car, but why you would is beyond me. You are robbing yourself of the overall performance experience from your car to save a $2.60 each fill up.

On that point, I just recently went through my first tank of fuel that the dealer put in. When I drove the car around, I noticed that it was hesitant when I applied full throttle, didn't have th tq steer that I remembered in the car that I test drove, and power was inconsistant. I attributed all of this to the dealer throwing in regular fuel. After filling up with quality premium fuel (I use BP, Shell, or Mobile gas station) and driving around for 100 miles, the car feels much like the test vehicle that I drove and now makes me very happy.

 

WOW, what an attitude.

And yes my response will probably sound like attitude because you keep telling us we are damaging our engines and will lose or warranties when in reality we are not, we are just doing as the manufacturer states.

At any rate MINI CON NOT VOID your warranty for using gas with octane less than 91. They only "recommend" using 91. they can however fight you if they can PROVE you used less than 87 octane. See information below.

Here in the North East finding gas at 93 is just about impossible (where i live and travel at least), and 91 octane at many stations is a lot more than 20 cents more expensive closer to 40 cents at times. I.E. 87 - $2.479, 91- $2.899 just this morning a 42 cent difference. Or at my current number of miles a year and average MPG about $320.00 per year or one car payment.


WRONG!!!!!!!!!!!!!!!!!!!!!!!!! Who are you to tell me whether I can afford a MINI or not.

Yes MINI does "Recommend 91 AKI octane, but they do make the below statements.

Quoted from the 2008 MINI Owners Manual page 95. Also see picture below of page 95:
"However, you may also use gasoline with less AKI. The minimum AKI rating is 87.

If you use gasoline with this minimum AKI rating the engine may produce knocking sounds when starting at high temperatures. This has no effect on the engine life."
End Quote:

And as MINI states above minor knocking has no effect on engine life. Although i might argue this as knocking is not good and if it gets really bad i am sure it would damage the engine or else the manufactures would not do something to stop it.

Again see the statement above from MINI that you can actually run 87 Octane gas perfectly legally without losing your warranty. Also see picture of page 95 below. And BTW MINI very specifically in column 2 of page 95 states what the gas can contain without losing your warrant. Guess what - All gasoline except E-85 and Flex Fuel meet these requirements. And they very specifically tell you not to use these fuels.

To any one who has had to pay for a fuel pump they should not have as it is covered by warranty and it would be MINI's responsibility to PROVE that the gas was bad as their car must be made to run on average gas in the USA.

 

After over 50 fill ups and testing with the seat of my pants dynomometer, my car runs better and has better spunk and gets better mileage on regular old 87 NOT Shell, Mobil or other so call top tier gasoline.

No i will admit that if it was put on a dyno it may show different, but until then what works for my car and maybe not yours is the lower grade gas.

Now I will also say that my car loved the No Ethanol gas I put in down south while on vacation and got much better gas mileage on that 87 octane than the 5%-10% ethanol gas we get up in the north east.

you will probably note that the car will get even more responsive over teh next few hundred/thousand miles, and is not due to the gas it is do to the wear in of the engine.

 

I'm just gonna point something out quickly and then I'm out. I don't really care what gas people use in their car, one can put diesel in there for all I care...

1. There's no need to lump entire North East and say that it's impossible to find 93 octane here. It's plain false. Entire jersey carries it, my recent trip across NY proved that I can get 93 there too. Maybe some mom and pop gas station don't carry it but those are irrelevant to me because I never go there.

2. As far as MINI says that "its ok if engine knocks" I'm gonna take this advice and do the same as I did when I read that MINI recommends me not to rotate my tires..... I'll ignore it.

 

O.k., so I'm the one who started this thread and I have great responses from all. I was expecting just a simple yes it runs better on premium or never use regular. But this was highly interesting and informing. I want to thank you all. In MY daily drives I can definatley get better milage on Premium, I never heard any knocking at all nor really felt any difference in performance. I will continue to stick to Premium (91) thats about as high as I can get that I've been able to find in the mountain areas of Colorado. Thanks to everyone that replied!!!

 

No need to be rude about it.

But did you really read what it stated

Here in the North East finding gas at 93 is just about impossible (where i live and travel at least),

I very specifically put bolded, italicized, underlined part in there it make it very clear what I was saying. Now I travel in MA, VT, NH, ME, RI, CT.

Maybe I should have stated New England rather than the North East

But then again most people consider the North East to be CT, RI, MA, NH VT, and ME, and NJ and NY to be Mid Atlantic States along with DE, MD, PA, VA and WV

So may be my statement was correct to begin with about the North East.

 

Not that it's relevant to this discussion, but since when is Buffalo, Syracuse, and Rochester become "mid atlantic" .... Its a FAAAAAAAAAR drive from Buffalo to VA...

 

In the gas cap it says 91 minimum. I use V-Power though

 

Wow I have only had cars that take premium for the last 10 years. It really isn't that much of a difference at fill up. It amazes me to find people scrimping that much to save $2 instead of putting what is recommend and beneficial.

 

I apologize for the digression here.

That is what i learned in school more than 35 years ago.

AND, (I am not saying everything on the internet is correct but)

http://en.wikipedia.org/wiki/Mid-Atlantic_States

http://www.sheppardsoftware.com/usa_...d_atlantic.htm

http://www.mass-awma.net/

http://images.google.com/imgres?imgu...a%3DX%26um%3D1

http://www.lifeintheusa.com/landhist...leatlantic.htm

http://www.virted.org/CB/MidAtl/MidAtl.html

http://sillysoft.net/lux/maps/Mid%20Atlantic%20States

And what is taught at Kent University
http://www.library.kent.edu/page/13501

and going as far back as 1901
http://www.researchhistory.org/Mapli...datlantic.html

http://www.luventicus.org/maps/unite...ticstates.html

and even as far back as 1749
http://www.amphilsoc.org/library/mol...tedimages4.htm

http://www.sheppardsoftware.com/usaw...idatlantic.htm

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=2588608701

http://www.statemaster.com/encyclope...tlantic-States

 

Wow!!

You had the internet back in 1749??

Forsooth and huzzah, that's awesome!


__________________________________________________

 

Mighty great post you made. Great selective searching skills

http://en.wikipedia.org/wiki/Northeastern_United_States

Oh and there's this too.
MAP, you can even ZOOM IN and look at all the states that are included in the Northeast

Thanks for your effort,

P.S. response to the bolded part of your statement: you know they used to teach that the Earth was flat too, right?

 

One report here said that MINI had the gas analyzed and found it had more than 10% ethanol. So, they refused warranty coverage on the pump. The owner could prove that he only bought gas from one station, and that station ended up paying because their gas actually had more ethanol than it said on the pump.

The reality of "MINI's responsibility to PROVE" things is that MINI will just deny coverage, then you have to fight it. You going to hire a lawyer and take them to court? MINI can afford to throw lawyers at it; can you? Probably cheaper to pay the repair bill.
You posted this page from the manual. Did you not read the "Use high-quality brands" part? Perhaps the reason you get poor performance out of the premium you've tried is because you are buying poor quality gas. The cheap way to increase the AKI rating is to add ethanol. Another reason to use high-quality brands is that they have detergents, and other additives that help keep the injectors clean and minimize carbon buildup. If you end up having problems with either of this, it will cost you more than $320.

 

I'm through with this convo. Put sodium silicate in your gas tank for all I care.

 

Wow! This entire back and forth is a repeat from the E90post on bimmerfest. Same exact discussion regarding BMW engines. Anyway, we usually put 89 octane in my wifes X3 which is being replaced by our 2010 MCCS when it arrives. I can tell the difference when I put 91 octane in when I'm on the Interstate really flooring it and passing. Never put enough 91 or 93 in to check the milage difference. My E93 335i is only given 91 octane or higher. The BMW owner manual reads like the mini, I wonder why.

 

Yes I did read that part and if you go to http://www.toptiergas.com/ you can find a listing of what BMW thinks is TOP TEIR gas brands. Well guess what, there is only one brand listed there and that is in my local (50 mile radius) and that is Shell, Well after 6 full tanks (12 gallons or more) of their premium gas (91) and having the car studder, shutdown a couple of times, genrealy not run well, have trouble starting (turn over of more than 30 seconds) i went back to LUK Oil gas and the car runs much better now. BTW their is only two shell stations in my local area and 3 times in a row I filled up at one station and three times I filled up at the second station thinking tha tmaybe there was something wrong with the first station. So this Top Tier gas thing in my book is CRAP.

Also I have stated a number of times that my car (not everyones) runs better and gets better gas mileage on the 87

Also if you look at the list at http://www.toptiergas.com/ some of the thought to be Top Tier gas companies are not listed. I.E. Mobil, Chevron, etc are NOT on the list.

And the point I was trying to make that on one seems to want to understand is that MINI does allow for use of 87 octane and will not void you warranty for doing so. The unfortunate problem is that many people here think other wise and try to force that thinking on other people.

So in your case if you get better performance and mileage on 91 or 93 then use it but do not tell others that they have to use it. Many other people use the 87 and get great performance and great gas mileage.

 

Not sure why you had a bad experience with Shell. Perhaps that station owner cheats. However, this line under the Use high-quality brands headline in the manual makes me think that not using top tier gas can void your warranty:
Unscheduled maintenance means you will be paying for it.

MINIs of the same model should not react differently to a given gasoline. So, when you say, "my car" it follows that it should apply to all MINIs of your model.

Interesting tha Mobil is not there. However, Chevron is second from the top in that list.

If you look at my posts, I think it should be clear that I'm trying to point out that there are two issues with gas for MINIs.
1. AKI 91+ is "highly recommended" but down to 87 is allowed.
2. Top tier quality gas (10% or less ethanol, and having top tier additives and detergent levels) is required.

You are telling people AKI 87 gas is better and that the top tier requirement is "CRAP". Who's misleadeing people?