Since my previous post was well received and while I'm not an expert....I did stay at a Holiday Inn Express recently.

Additional clarification. The knock we are worried about is caused by the heat of compression causing ignition, rather than the timing firing the spark plug to cause ignition. This ignition from compression alone causes a pinging sound simular to the sound of a diesel. This is why pre-ignition is sometimes called "dieseling". The noise is detected at very low levels by the MINI's knock detection system which retards the timing, making the spark plug fire at a time when the piston is at a lower position in it's compression stroke...in other words, it makes sure the fuel/air mix is ignited by the spark plug before it ignites from the heat of compression only...presto, no knock.

Because the piston is no longer at it's optimum theoretical position for maximum power production, a very slight reduction in power and/or gas mileage could occur. Your engine will not be damaged in any way by this change in timing...not to worry.

The above information is certified correct to the best of my knowlege.

P.S.......I use 93 octane in my MC.

 

WOW! I stayed in my own home last night, my manual says premium, and I have a headache. 91 or better it is. The "I's" have it. I hope this thread helps the first person that posted thier first post in here. Posts aren't always this rant-ish.

 

Unfortunately, things like this aren't stickied around here (no car-guy topics are), and it'll be gone through AGAIN in a few days...probably for weeks/months. It's too bad the things that ARE stickied, like 'register for your super special forum number' and 'find a local buddy' and 'the latest mini ad' are 'important' and the topics of a car forum.

 

 

BYE

 

Premium.

 

Out here in the cornfields the cost difference between regular and premium is shrinking. Used to be 20 cents difference and lately it's only ten.

 

Guys,

I was just at my dealer, and like every time I visit, I asked if there was any fix for the stalling/stumbling upon a cold-start. He said no, except MINI USA has told them to recommend that any customers complaining of cold-start stalling, should go down to 87 octane gasoline, (even MCS drivers).

That was the second time that he told me this. I am totally confused.

Our owners' manuals clearly state 91 octane. Now they're telling me to use 87 octane. Who do I believe?

Personally, I have decided to ignore the dealer's hackneyed advice, and stick with my 91 (or 93) octane gas. I don't care that it costs more, or that my car stalls on cold-starts. I would rather ensure the longevity of my engine by using the proper octane gasoline, than not.

So, has anyone else been told to go down to 87 octane? Have you? Did it solve the cold-start stall?

Let us know.

 

I would think that if Mini officially made that statement there would be a TSB advising of taking that action based on customer complaints. I would certainly want to see that TSB and have a copy for any future results before following any word of mouth from a dealer.

 

91+ octane is only necessary for the 5% of the time most people push their cars hard to the point where 89 octane would cause detonation. For the other 95% of the time, a higher octane gas is a complete waste of money. If you're one that drives like an old man in your commute to and from work, there is absolutely nothing wrong with 89 octane gas despite what the manual says. Of course the manual is going to tell you to use a higher octane gas because the car was made to be driven hard, but don't just blindly follow the manual. If you drive your car like it should be driven, spend the extra $.10 per gallon.

 

Yeah, and if I damage the engine, you will pay for that as well, right?

 

The manual says premium, the gas cap says premium, and your MA should have told you premium. If you don't run premium you are giving ammo to the service department to deny warranty service for certain maladies that may result. You really should stick with premium. ESPECIALLY for a S model.

 

Short and sweet!

 

to add more confusion to the fire, this popped in the mini mania 2 thread over in the DCMM subforum:

" Judging how poorly a MCS runs on +91 octane in the summer I can't see using anything more. We have been running much smoother using 89."

this part of the thread was about whether 100 octane race gas would be available for the driving class ...

 

For the price of gas and the way we all seem to love our MINI's it's a small price to pay. About a dollar more a tankful. I don't have a prob with that cuse "Spike" is definitely worth a dollar more a tank. So lets just hope the price levels off soon so it won't continue to be a pain in the a$$ at the pump.

 

Another thought...

20K miles a year
Price of 87: $3.00 gallon
Price of 93: $3.20 gallon

93 Octane getting 25 MPG: Total Gas Cost per Year: $2,560
87 Octane getting 24 MPG: Total Gas Cost per Year: $2,500

Savings of running 97 Octain: $60
% Savings per year: 2.4%
Savings per Month: $5


Hmm....

 

OK people......All of you guys are just throwing "what if's" out there and with no hard evidence about what your saying. Nobody knows if it hurts the gas milage or power ( which using lower octane gas would ) unless someone does a test if your all concearned about this.....i will tell you this.....Like everyone else said....the manual tells us to use 91 or better gas.....For the people running into drivablity issues, u now know why. Just because there is something cheaper for us to use, doesnt mean you should use it. Take your own risks and watch yourself being at the dealer more times than you wanna be.


And also.........We here at the dealerships are not scientists so we wouldnt know what gas your running by looking at it or tasting it . There is no way we would know other than what you tell us your running in the vehicle.

 

I found this in the Wikipedia, the free online encyclopedia:

There is no 91 octane fuel here in the NorthEast. Is it possible that the 87 they are selling is indeed the 91 our cars require? The entire reference is here: http://en.wikipedia.org/wiki/Octane_rating

I have never put anything other than Sunoco 93 in my '03 MCS and I have had no problems what so ever. No stumble and only an occasional not starting the first time when cold. I am not interested in using anything less than the Mini engineers recommend. But is it possible that the Sunoco 87 actually is what is recommended?

I thank you all in advance.

Rich

 

R u kidding?

Thats all there is around here.....I only see 89,91,93 octane all over NY and the tri-state area. or maybe im wrong.

 

What Randy Webb told me over a year ago. The MCS has anti-knock sensors that will detect detonation and retard timing (as much as 11 degrees) or, dump more fuel to cool the cylinder or both. So, while you will most likely not hear a pinging, you will sacrafice power and/or milege by running a lower octane. Putting around town may not be a big deal but, if you jump on it.. now the ECU will start its dance "Da Da Da Retard timeing, Bo-wap, Bo-wap... ad fuel, wup-tee-dee do both, la la... la la"

 

WTF..... bo-wap bo-wap!

 

Gas is an addictive topic .
It's been mentioned before, maybe without evidence, but in terms of you Mini-heads driving higher than 91, I've read that it's a waste; i.e., mileage and power not improved... the ECM just compensates without any bonus to car and driver. Is that true?

 

I have been looking for the last three days around the New York/New Jersey metropolitan area. All I could find is 87, 89, 93 and Sunoco 94 no including the race gas places.

I can not find any branded gas with 91 octane.

But my original question still remains. Is it possible that the manual referring to 91 is on a different scale than the 89 commonly available here in the North East? And that 89 here is actually the 91 referred to in our manuals?

Rich

 

I lent my 03' MCS out and he filled 2 tanks with 89 octane i always fill it with 93 it won't do anything in the long run will it aslong as i continue on with the 93?

 

You're fine. If you drive it hard with 89 octane, the ECU will retard the timing. I wouldn't recommend doing it on a regular basis, but aside from the lost performance until you refill with 93 octane... You're fine.

Beat your friend severely about the head and shoulders just for good measure.