Premium fuel a must?
 

Hello,

I just recently purchased a 2009 Mini Cooper S. I will be picking it up in a couple days (very excited). I heard that Minis require premium fuel. Is this true? I own a Lexus that says "Premium fuel only" on the manual, but the dealership says that is not true. Can you put Regular Unleaded fuel in Minis? FWIW, mine does NOT have a JCW package. Thanks!

-G.B.

No, it's not needed. 89 is recommended, and 93 will give you no added benefits.

Ok thanks! The reason I ask is because I've heard people say that if you don't use premium fuel, you mess up the fuel filter. Good to hear that you don't need premium. :)

-G.B.

ABSOLUTELY WRONG!!!!
Read the Manual ... look at the gas cap !!!
I've talked to many service advisors , while you can run lower octane it will cause less power as the timing is retarded to prevent knock detonation ect.
It will also cause build up in the valves ect that can lead to mega pricey repairs.
If you can't afford the $2.00 extra a tank go buy a civic

So premium IS required? I keep hearing mixed things and I don't know what to believe. I don't wanna screw up the engine, but I'd like to save a buck too. If it's required, then I definately don't mind coughing up the extra 2 or 3 dollars for premium, but that adds up and I'd like to save if I can.

-G.B.

yes it is

You car engine employs forced induction which pushes in more air so that you can have more power when mixed with fuel and spark.

high compression and forced induction engines do require higher octane fuel for long-term viability. Octane measures the ease of detonation the higher the number the harder to make da boomba!

lower octane fuels when under high compression and or forced induction can prematurely go boom creating knock. BV is of course correct when your ECU sees significant knock it will retard timing to limit it and that will cost you power. run your car like that for years and you will coat the inside with gunk.

The opposite is also true run a car designed for 87 on 93 for long periods of time and you coat the insides with carbon waste money and screw yourself

from an energy stand point gas is gas neither 87 or 93 per unit volume provide any more or less power. The difference is the energy required to liberate the fuel energy!!! Your engine is designed for high compression forced induction 93 octane fuel.


use it Mkay?

Premium fuel it is
 

Thank you very much. This was very helpful. Premium it is!

-G.B.

89 is considered premium in some places, and that's what is recommended by MINI. I've driven 80K sports cars, and they recommened 93+, so that's what I used. You're wasting your money if you put higher than recommended fuel in your car.

And, to accurately answer your question, about is it "required," the answer is still NO.

You should receive better gas mileage (1-2mpg more) and better performance....but, "required" it is NOT.

I put Premium in, myself...because it's cheap and what's the point of a mini without the best possible gas mileage and the drivability (increase performance).

Sorry, if you would have said "desirable" instead, would have answered it differently.

enjoy the car! This is for my wife, but I'll drive it for groceries every once in awhile.

89 is MIDGRADE when it says premium only Premium =91+ READ the manual ...

Trust me USE the Premium .... This is from a friend Sam who Also happens to be a service manager at a dealer
Sam "The MINI's seem to be good cars & long lasting, but run hight test gas of good quality in your MINI. I've seen MINI's coming in carboned up. Some so bad that one of the valves do not close all the way. That leads to a burned valve. While your MINI will run on regular it's the regular fuel that leads to those carbon deposits."

I told Sam that I add a bottle of Chevron Techron at every oil change.

Sam "Techron is good stuff, but use a good quality high test fuel too. Shell, Marathon & even BP now have additives in them to keep the valves clean. Shell is the best"

There you have it. Some good advice from someone that I trust. I know some of you run regular to save a few cents on fuel. You do so at some risk it seems. You will never save enough money buying regular to pay for the potential damage it causes,

Motor on, with high test!

Thanks! I am convinced. :)

-G.B.

I always try to use 91 but sometimes I use the one just below it when I'm low on funds. I took my 2007 mini cooper s in to the mini dealers just a few days ago because the engine was "knocking" (?) and it was because I used the not so premium fuel. The service guy who has been helping me since I first got my car told me that even though many gas stations say its 91, only Shell, Chevron, and 76 (at least in the Sacramento area) are truly top tier 91 fuel. They recommend 91 because it has a lower content of ethanol which can mess up your engine, they have a little booklet at the dealers. You can also buy some sort of oil detergent to remove this stuff from the engine. Anyways, I've learned my lesson, always use premium.

You car will only require premium fuel if it pings on regular. If you put in regular gas and it doesn't ping, then you are fine. The gas itself is the same, the gas company simply adds octane to their premium grade. They may also add some cleaning agent but you can do that by purchasing some STP gas treatment and add it to a tank of gas after every few fill-ups.

As mentioned BEFORE the car detects predetonation and retards the timing to prevent it, this cuts down on performance and can cause SERIOUS engine troubles in the long run...but hey if you won't listen to a service manager or me go ahead and ruin your car

That's funny, because my service manager said "no added benefits." What's really funny is that we're all listening to service managers who quite frankly are usually retarded. In my 420hp V8 RS4, all I'd ever think about putting in my car would be 93+. With my wifes mini S, I still put in 93...but that's not what Mini of Tampa said.

Fuel grade for NON-turbo Mini
 

One of the factors we are looking at while deciding whether to get an "S" or not is fuel cost.
Since it will be replacing our 2005 Prius, I'm a little sensitive to this.
Carol's car before the Prius was a 1998 BMW Z3.
89 octane was the recommended grade for that car.
As a test, I did run a tank of 87 octane through it, with a result of nearly 4 mpg less.
I always use Chevron (Texaco) or Shell for the cleaning additives.
Question: does the non-turbo Mini need 89 octane, or is it happy with 87?
Being an old-school type, it was always a rule of thumb that anything less than 10:1 on a normally aspirated engine did not require premium fuel, but I don't really know where the regular/ mid grade break point is.
I found a REALLY low mileage 2008 "S" that's tempting me, but I need to settle this issue.
Off topic: I drove the new Honda CRZ last week.
In "Sport" mode, the paddle shifters impose gear stops on the CVT tranny and it feels just like the auto version of the Mini!
Carol says it's not as cute, however, and you know how much weight THAT carries! :-)
OTOH, you can put the CRZ in "Economy" mode and get 58 mpg highway, according to Motor Trend.
Thoughts anyone?
Bob

Both state premium fuel only

Premium gas for non-turbo Mini?
 

Bad venge,
Are you quoting the Mini manual?
I was looking for some experience-based comment from someone who had actually tried mid grade or regular gas in a standard Mini.
It does appear that you and I are the only ones around!
Thus emboldened, I will give my layman's opinion that if you are operating a normally aspirated engine with less than a 10:1 compression ratio and not using an advanced timing setting, premium gas gains you NO benefit at all.
There. That should bring forth the expert commentary! :-)
One disclaimer: I do not know the compression ratio for the Mini engines.
Bob

I've tried mid grade as well as high test , my performance and mileage suffered on both the S and the regular mini's.
Also the deposits are what worries me

Look folks the S means it is forced induction! there is not a turbo or supercharged car on the planet that will run well on mid grade or regular octane gas. When I asked my dealer multiple people there insisted on premium. when they fill up the cars in their fleet they use 91+

I love people who sit and say "i did it and it worked" they always leave out "for now"

Problem with the internet is that you have to decide who is credible and who is not. why not google octane and try to understand what the number actually means. Its all about the threshold to combust the higher the number, the higher the threshold. High octane does NOT have more energy per volume it allows the explosion to occur in a smaller space with the same amount of air.

if the bomb goes off too early you waste the energy and damage the engine which is why Mr on board computer retards timing.


You do not buy a sports car if you do not want to buy 1K worth of tires every 15-20 thousand miles. Do not buy a high compression or FI engine set up if you do not want to pay 10 cents or so more per gallon. really for a 10 gallon fill you are talking about a dollar.

But what about the NON-turbo Mini?
 

I have no problem with the requirement for premium gas in the forced induction engines.
The answer I am seeking is why premium (or even mid-grade (89 octane), really!) is a requirement for the standard Mini without a turbo or supercharger, unless the compression ratio is 10:1 or more in that engine.
So, can anyone state (with certainty) what the ratio actually IS? (and in this case you DO know what "is" means, Bill!) :)
And at the Chevron station where I buy my gas, premium (93 octane) is 30 cents a gallon more than regular (87 octane).
No, I'm not pursuing false economy at the expense of damaging an engine. Our 1981 Porsche 911 SC ran just fine on 89 octane as did our 1998 BMW Z3.
Since here in east central Florida, it is not unusual for a weekend days drive to hit 150-200 miles or more, when the price of gas goes nuts again (remember the $4.00/gallon for regular gas not so long ago? And premium grades were not even available for periods of time) it could well be a matter of having to restrict driving more than we really want to.
But really folks, since we are still in the purchase decision phase of which Mini (Standard versus "S") or the new Honda CRZ (for long term reliability), this is more a matter of becoming an informed consumer.
BTW, you should see what the J.D. Powers survey of Mini owners (available on the Carfax reports) says about the build quality and reliability of ALL Minis! :( THAT will probably go over like a fart in church! :)
Bob

well I do not know if you have gen1 or 2. regardless find the specs and use this site
http://www.csgnetwork.com/compcalc.html
or get a compression tester and measure yourself. BMW tend to use high compression

as to your imperial data on using mid grade regular gas for a car rated for premium

IS there proof you did not damage your car and decrease its lifespan? (and in this case you DO know what "is" means, Bill!)

Got my answer
 

T-bone and the group,
First, we don't as yet OWN a Mini.
Yesterday we went to Orlando Mini and I had a (VERY hot!) female sales person get an owners manual from a new car so I could read what it said about fuel grades. Here is what Mini says about fuel: While they strongly recommend 91 octane for ALL Minis, they DO allow the use of 89 octane in the "S" and the JCW, and 87 octane in the standard Mini, acknowledging that some spark knock WILL occur which they say will NOT harm the engine.
Given that, I would have to see with my own eyes that a non-turbo Mini has trouble running on 89 octane before I would be convinced, given this statement from the company that builds the car.
We also visited a Honda dealer who has a new CRZ tricked out with all of the goodies. It looks considerably better than the stock one (especially with the rear spoiler and some pin striping), and can be had for around $28,500 or so.
Since we are coming to the conclusion that we would have to special order a new Mini to get what we really want in a new one, I am haunting the Auto Trader and Craigs List sites in hopes of finding that car as a clean late model used.
Bob