With the Cooper is using premium gas required? Or will mid-grade or regular suffice?

 

Although the manual indicates to use premium, my sales rep said the car adjusts to whatever octane fuel it receives. I'm saving tons compared with fueling up the minivan that a bit more for premium doesn't hurt and my MINI is worth it... vroom...

 

Well, the minimum oncane level for fuel you should use in the mini is 91... Premium is 93... You're right that it will run with regular unleaded gas, but you'll probally have a decrease in performance, and possible shorter engine life... :???:

 

most modern engines have "knock sensors" and retard the timing to compensate. this decreases performance. if you don't care about performance then by all means do it. but it may have adverse affect on your engine.

forced induction motors (cooper s) need higher octane gas because they are running much higher compressions and lower octane gas detonates too soon.

just use the highest, its like going to run you a buck or two more per fill up...small price to pay for driving a cool car :smile:

 

We have 3 main types of Unleaded petrol here in Australia. Regular 94, octane and Premium, 96 octane. Shell has released a petrol called optimax and it is 98 octane. It is apparantly more dense so you get more range per tank. Generally it is about 7 cents more a litre but it is worth the money. Most companies are now switching from a Premium Unleaded to the new 98 octane range which will in the end leave us with 2 types to choose from.

When I get my Cooper S I will be running the optimax becasue I want as much power as I can possibly get !

I have used it in my normal car and it makes a world of difference. It is amazing the difference a couple of points of octane can make.



_________________
Time stops for no one.... But people always stop to look at a MINI

 

If the manufacturer says to use a certain grade of fuel, use it. Why would one second guess the engineers?

While pumping a higher octane fuel into your tank than the manufacturer recommends is a waste of money (once the required octane level is met, there is no performance benefit beyond that level) the deal doesn't work both ways.

The higher octane fuels are designed to eliminate pre-ignition (knock) at certain cylinder pressures. The nomally aspirated Cooper has a high compression ratio. The Cooper S has a much lower ratio, but the intake charge is being squeezed by the blower. While knock sensors and the on-board computer will retard the ingnition timing in order to prevent engine damage, (knock can be very hard on the internals, especially over time), the retarded timing will result in less power, and it will be noticeable.

 

When they altered the engline for a lower octane for use in the US, how much actual performace if any is lost? And another thing.... 163BHP? isn't that using DIN? If it is, the cooper according to american standards should have 215hp... Just a thought

 

How about Premium Unleaded with Ethanol? How good or bad is for a Mini Cooper S?

 

Ethanol? That's a good question. I remember when ethanol (or some other form of alcohol) was first introduced as a fuel additive in Southern California some cars didn't like it. Seems like there were problems with rubber/plastic components that were swelling up, or becoming brittle, or some other jazz. I think there were problems with the fuel lines on some cars, too. But I don't remember the details.

Gonna hafta e-mail the folks at MINI and hear what they have to say.

 

I sent this Ethanol question to a Mini Representative (note: I don't own a Mini yet)

question/comment:
Here in Iowa I can get premium unleaded gasoline but it contains Etahnol. Do you know if this is good or bad for a Cooper S?

answer:
Good question! This info is actually laid out for you in detail on page eight of the Owner's Manual. Fuels containing up to and including 10% ethanol or other oxygenates with up to .8% oxygen by weight will not void the applicable warranties with respect to defects in materials or workmanship.

 

I, too, wrote MINIUSA regarding theh ethanol/premium issue:

My question-- I know my new MINI requires premium grade fuel, but here in the US many oil companies add alcohol to the gas. Are there any problems associated with using gasoline with alcohol added, or can the MINI use either with no ill effects?

Reply-- Thanks for writing in! The MINI is quite a tough little machine! Although MINI recommends medium or premium grade fuel, the engine is designed to run on any grade with a subsequent reduction in horsepower. This is achieved by using active knock control which means that the same engine tune can be used for virtually all markets in the world, irrespective of local fuel quality, and where various qualities of fuel are available in a market, there will be no restrictions placed on the customer. So rest easy, the MINI can use almost any grade of fuel, even with alcohol added, and not have any negative effects.