Well, you might want to stay away from Utah then...there is no 93 octane! 91 is the highest...so make sure you stay far away from here.

And just so you know the engine doesn't knock with 91 octane ...even with the JCW upgrade. Where do people come up with this stuff

 

Huh. Thanks to California's 91 octane limit, I'll just never know.

 

I'm somewhat new to this forum, most of the time I just lurk around the forums for information and so far all information here has been helpful and almost all my questions have been answered so thank you guys. But to the point ... there is 100 octane in the Bay Area at a 76 gas station. Dr Obnxs, your location says Woodside, CA. If I'm not mistaken you're near King Mt. and Pagemill am I correct?. The 76 gas station after exiting off 280 on Woodside (I forget the cross street) has one gas pump that has 100 octane. I think the only reason why it's on only one pump and not as noticable is due to its cost. Last time I checked, it was about $4.89. Just wanted to share if no one has really known about it.

 

And it's not going to be a problem. As a matter of fact, sometimes the cure for problems can be switching to 89 octane gas.

It almost seems that people cannot help themselves from equating "high octane" with better running, more power, etc.. Not always true, and often nothing more than a waste of money. Oil company profits are much greater for higher octane fuels than the additional cost to make them warrants. I'm sure they're happy with the marketing success they've had that "premium" automatically means better.

 

Opti, yeah I go to the 76 on Woodside Rd for the hot gas. There's a thread around somewhere on stations that have better than 91.

Res: If you have a car that doesn't have a knock sensor, and runs at a very consurvative fixed timing advance, then no benefit will be had from higher octane. But if the car does use a knock sensor in setting ignition timing, then increased octane will give you power until the ECU won't advance the timing any more.....

Here's a suggestion. Next tank, get some 87 and put in a few gallons. Go drive for an hour or two. Then fill up with premium, and go drive. See if you feel a difference...

Matt

 

My MA told me to use 89 octane after the break-in period because of all the additives in the higher octane gas.

 

your MA doesn't know sh*t. There have been some post about lower octane gasses not haveing the same hard starting issues that some other have been reporting. But you are throwing away power and gas milage to do this.

Matt

 

here is the Tech Service buletin

http://www.alldata.com/tsb/BMW/11438...06/130206.html

Tell your MA to go talk to the mechanics

 

Well, according to that TSB, I should use Shell 93 since it's the only thing that's available from the Top Tier list. We only have 87, 89, and 93 octane in Ohio... Descisions decisions...

 

My MA had mentioned that the cold start problem was due to the switch over to 10% ethanol, and they were calling in MINI's to get their computers updated to fix the problem...

 

We do need to use premium fuel, but also make sure it is "top tier" not cheapy premium. You can check www.toptiergas.com to see which brands meet the standard in your area

 

if you read the BMW tech stuff, this is all about long term build up supression. It also states (correctly) that it won't prevent build up, just lessen it. Read the Top Tier specs, and it specifically requires ethanol, and some gas still has MTBE, so you may be avoiding perfectly good gas for no other reason than the oxygenate that is used.

Does anyone other than me smell a marketing campaign? I use good gasses, and still when I had my injectors cleaned and flow tested, there was surprising degradation in just one year of use.

Just cause they say it doesn't mean it means anything......

Matt

 

Hi! I'm new to the blog and have 2 minis!!! In my 02 Cooper I tried Premium and could never go back to regular. Performance was dramatically increased. In my 06 MCS, of course on premium... But, I noticed a big difference with Premium in my regular cooper...for the better

 

I auto-cross my yellow/white 2003 mcs and find if I use any brand of fuel other than Chevron Premium, ie: costco, safeway,arco,texaco,etc, my track times are sometimes more than a few seconds slower. She (Sunny) just does better with good gas. I am in my third year with her and she is strong and quick.

 

But most gas is all the same, delivered from common distribution points. Additive packages are different, added en route in the trucks.

Also, FWIW, gas pipelines may not deliver the exact same gallons to the customer that are put in at the refinery..... Chevron may put in 10,000 gallons at one end, and recieve a different 10,000 gallons at the other end of the pipeline at thier distruibution center.

Check to see if the gasses use MTBE or ethanol as an oxygenate, there may be some difference in energy content there.

Matt

 

Just need to get out the blackboard and start a lesson here. People seem to be under the mistaken impression that octane equals power. Nope. Gallon against gallon, low octane gas produces MORE power.

The higher the octane rating, the more additive the gas has to keep the gas cool during the compression stroke of the piston (remember your high school science: the more you compress something, the hotter it gets). Call it coolant if you want. This way, in high compression engines (say 9:1 and above), the gas doesn't pre-ignite under the compression stroke.

Now then, if your car doesn't NEED high octane gas, DON'T use it. High octane gas will not burn completely in a lower compression engine, and will leave carbon deposits on your piston and your valves. Carbon is a wonderful insulator, and carbon encrusted valves will burn, because the carbon prevents the valves from cooling off.

Just some generic edumacation!

 

what Gromit801 says jives with an experiment that was done by BCM Ducati some years ago that I heard about. From what I understand, they did two dyno runs with the same Ducati motorcycle (stock engine, I believe). One with premium fuel, and another with the cheap stuff. The dyno charts proved that the bike made more Horsepower with the cheap gas. After that, I always ran the cheap stuff in my 1995 M-900 and never had a problem.

With my '06 MCS, I've so far been following the manufacturer's recomendation and use only premium fuel. Makes me wonder though given that the compression is not very high, would there really be any issues running the el eheapo fuel.

 

If you have an engine that doesn't use a knock sensor to adjust timing, then as long as the motor doesn't knock, the energy density of the fuel will tell you what will make more power. Many of the items used to raise octane actually have lower energy density!

For our Minis, they DO have an knock sensor. Data has been posted (by me and others) that shows that crappy gas gives you timing retard that robs power and efficiency. That's because with a knock sensor, you can set the base timing very aggressivly, and have the knock sensor just pull timing when trouble is detected. Without the sensor, you have to set the timing maps conservatively (and hence leave power on the table untapped, because you have to tune the motor for the worst conditions it will encounter).

And yes the compression ration is low on the S, but don't forget it's a forced induction motor, so while it's running 8.something to one, a stock S gets 10 lbs of boost, or over 1.5 atmospheres. That's roughly equivalent to a 12:1 or higher compression ration on a NA car.... Something to keep in mind.

But I suggest you go get a quarter tank of 87 and drive it for a while... I think you'll feel the difference....

Matt

 

Very well stated, but I would not confuse 'crappy gas' with low octane. You can have crappy premium gas too.
Too many associations are made that cars that run premium are running on the 'good stuff'. Technically, regular produces slightly more BTU per volume.
If the difference between additives and fuel grade were that great, there are a lot of modern cars and trucks that are made to run on regular (and MOST modern cars do these days) that are doomed for premature overhauls. With all the high mileage Corollas and Civics still running around I doubt that.
As far as these 'upper-tier' fuels, etc. kind of tounge-in-cheek for me. Kind a like the Public Utilities Commission monitoring energy suppliers. A rubber-stamp agency IMO.
Same goes for Costco, Vons, etc. being bad gas. You can make your own evalutions and determine what BRAND your baby seems to run best on. Just do it under similar temperature conditions, same roads, grades, etc. If there is a pattern it should show up in time, either in how the car feels and/or your average mpg over a few weeks. I think there is merit in the stations with highest turnover giving you an edge.
Back on track, sorry to digress, I can not imagine running less than 91 octane in any pressurized engine.

 

hi, all
I'm new too here. I have 03 MCS and 06 oddyssey. I dont know about mini and preminum, but for my oddyssey I really felt that it lost power when I use regular. Think about the price, in colorado which I live, diff. price between regular and premium is about 20 or 30 cent.
You only pay 3 or 4 dollar more for premium with full tank!!!

 

New to site & just wanted to add my own experiences with premium. I bought a used 2002 mini that didn't have a service manual with it & innocently bought 89 regular not once, but twice! When I found out about my error, I bought 91 premium & have been rewarded with good mileage & no engine trouble so far. In fact, my yellow/white Mini zooms up steep hills with the attitude of a free range mt. goat!

 

Maybe even less, because you may be getting better mileage too.
Although, if you drive a lot at high altitudes, I would think a standard engine should run fine on regular.

 

Reguler gas and premium gas energy content overlaps.

Regular gas ranges from 30.53 to 32.67MJs and premium gas ranges from 31.76 to 33.93MJs. (MJ = milli-joules)

The best regular gas contains more energy that the worst premium gas, but the relationship doesn't hold for every sample of regular and every sample of premium.

Premium gas doesn't have additives to help it stay cooler. The additives/blends of hydrocarbons are there to help premium gas resist preignition ahead of the advancing flame front (triggered by the spark plug).

Essentially the gasoline is harder to ignite. But not slow to burn. Hard to ignite but fast to burn is not unheard of. Most explosives are hard to ignite. But once ignited (blasting cap, fuse or...) the explosive burns with all the speed it can muster.

Premium gas usually (but not always) have a higher content of detergents that help keep engine deposits down, and will work to reduce even eliminate engine deposits, not increase them, but even so, premium gas is a waste in most low compression engines. (As engines age, however, their octane requirements can increase to the point a higher grade of gas should probably be used, but no does this, follows this.)

Auto makers have no vested interest in spec'ing a higher octane gas than the engine needs, can make max. use of. If an automaker specs a certain grade of gas, it should be used. Emergencies excluded.

If one finds his high performance engine runs better on a lower octane gas vs. its spec'd high octane gas, he's got a problem with the engine or engine managment system. The problem is not that the auto maker went overboard and spec'd the wrong gasoline.

Automakers are on the hook for engine/emssions subsystem performance via new car/emissions warranties. They're not going to risk raising their exposure in this area by spec'ing the wrong grade of gas just for fun or by accident.

Sincerely,

RockC.

 

wow, this is interesting, didn't realize it would make a difference.

 

We all have opinions based on experiences and other sources.

Using what is recommended by the manufacturer for your particular vehicle is the safest choice.