Modern vehicles have sensors and electronic controls that allow them to react to various operating changes.

One such is octane rating of the fuel being used.

The 2011 MINI owners manual covers fuel specifications as:


has no effect on the engine life.

I was driving a CX-7 (2.3L Turbo, 244hp) during the last round of [really] high gas prices, this vehicle also was premium "highly recommended", and of course the usual discussion of regular vs. premium on the enthusiasts forums took place ("it's fine, the ECU & stuff will adjust accordingly" vs. "you'll blow up your motor and void your warranty", and points in-between) as folks got tired of $60-80+ fill-ups.

I was curious about what results folks have seen on the R56 when running 87-octane, did a search for "dyno results" and "octane rating" but didn't find anything conclusive.

I did find this link:

http://blogs.insideline.com/roadtest...its-power.html

where InsideLine dyno'd a 2010 2.0T VW GTI with 87 then 91 octane, with [just] a small decrease in HP. About what you'd expect if the ECU was dialing back [whatever] to account for changes in esoteric gas-flame parameters, cylinder pressures, and the like due to volatility of the lower octane fuel.

What I was wondering was, are there any longer-term R56 owners who use 87 octane on a usual basis and have found it economical to do so?

 

Not bad, good write up. But using a low octane can result in a blown motor which makes 0 HP and 0 torque

 

I can think of better ways to save $.50 a day than using regular instead of premium.

 

Note that 87 is too low for the turbo charged engines.

 

I went the other way. I use 94 octane whenver I can.

I get smoother running engine, a little more hp, and better fuel economy, wihich balances the few cents per liter I pay for the 94 over the 91

 

oy...here we go again

For what amounts to around a whopping $3.96 difference per full tank...blows my mind why people insist on trying to run lower than required on a high compression/boosted motor.

 

Well said.

 

To answer your original question (which was: anyone out there use 87 octane as a rule, and if so what's the deal?): I don't think I've encountered a regular 87 octane user in my 5 years on these boards. Occasional/curious users yes.

 

My two engines drank 93 octane courtesy of sunco and never had problems... thought the min octane was 89 not 87?? but ive always put the higher octane in my minis and never had a problem. its a small investment.

 

Never used 87, even though mine is a Justa. I think the manual states that 87 is the minimum for the Justa and 89 is the minimum for the S/JCW. I'd have to be really hard up for cash to use 87, but that is just the way I feel. I am so used to putting "The Good Stuff" in my car that I almost put 93 in the wife's Accord a week or so ago.

 

Out here in the Denver area the highest I have seen is 91. Which is what I use. I once may have used 87 out of habit (Switching from Accent to MINI) but not sure. After I got the gas and had driven off I thought what gas did I get. Unfortunatly I didn't keep the receipt so I don't know. But if I did it was only to top off the tank (Like 3 gallons) and I didn't notice anything.

Is there a place in Denver that sells a gas higher than 91? Presuming that that 94 would be better than 91 I wouldn't mind trying it.

 

Call it programing, but the thought of putting 87 into my MINI makes me feel guilty. like I'm doing a disservice to my buddy.

 

Having read the same thing in the manual you did, I am running 87 octane in my 2010 Justa automatic and have found no difference in MPG (32 according to Fuel Log) or performance. Also, I live in a hot climate and have never heard a "knock" of any kind. It is my belief that the MPG reccomendations may based on how the car qualifed for EPA certification and not on whether the engine can handle it as the manual clearly says it can. I came to this conclusion after seeing BMW comments that "using lower ocatane may result in lower gas milage or higher emmisisons. Probably not much else they can publish based on legal issues. Whether the savings is worth it seems to be just a personal issue and, to me, it is worth it.

 

Don't worry about using lower octane up in Denver. The lower atmospheric pressure effectively lowers the pressure of the air in the combustion chamber on a non-forced-induction car. As a result, the engine is less likely to ping and lower octane can be used. You don't generally find 85 octane in lower-altitude states, but I remember seeing it all over Colorado.

The 91 is probably preferred, but 87 should work just fine for you. I wouldn't go lower. Going higher is completely unnecessary, especially for a Justa at high altitude.

 

Here in FL 93 is the norm at most stations for premium, theres a few that do sell 91 at 15 cents cheaper or so. I gave it a try for 2 tanks. Power seemed the same, but MPG went down by about 3Miles. So i think i'll go back to 93 next tank around. As well as a few months ago a station only had 87 or 89(mighta been the pump i was too tired to bother figuring it out) But the car the same- ran fine but poorer MPG. so. 93 really is the way to go, unless 93 gets significantly higher (08 -nonturbo cooper)

 

I think Colorado only sells up to 91 octane.

But on a real note to the OP. Octane levels are there to let you know the gasoline's ability to resist premature detonation aka knock. It can cause damage over long use but, if you don't want to spend the money on higher octane don't who cares it is your MINI.

 

i pump shell v-power here in Singapore which is slightly higher than 98 octane o.o

 

But I bet it is rated on a different scale.

Four grades of petrol are commonly sold in Singapore. Diesel and unleaded petrol with octane levels of 92, 95 and 98 are widely sold. Octane levels conform with European octane ratings and roughly correspond to American octane levels of 87, 90, and 93, respectively. Shell also market a fifth brand of fuel under the V-Power label, in addition to 98 octane petrol. 98 octane V-Power is marketed as having an FMT additive and "formulated to improve performance and responsiveness" [21] and sells for approximately 15 cents per litre more than Shell's other 98 octane fuel [22]

 

I'm all for saving money, but the cost savings are pretty insignificant here. I have a buddy who will drive an extra ten miles to save a penny a gallon on regular gas. He drives a brand new Lexus. Some people baffle me.

 

use the octane rating recommended by MINI. skip the cheaper stuff.

now the issue I have is the ethanol added to gas. i seem to loose a lot of the pop and burble when i fill up with anything w/ ethanol added.

 

Perhaps slightly off topic

ETHANOL - E10

I have had my '09 justa cooper for 10 months now and more than 10k miles have made some observations about fuel that I would like to share and see of others have similar experiences.

I am fortunate where I live to have several stations that have no-ethanol gas. I use the premium grade which is 93 octane. The price penalty for this gas is usually 10% over the cheapo stations and price is usually about the same for the big-brand stations. My measurements indicate that I get about 10% better fuel milage with the ethanol-free fuel. That is for around-town driving as well as for trips out of the area that are short enough where I can return here on the same tank of fuel.

On longer trips that entail several tanks of whatever brand, ethanol-containing fuel my milage drops and does not return to 'normal' until I run 2 or 3 tanks of ethanol-free fuel.

My numbers are: Highway 40 vs 36 and City 36 vs 32.5, ethanol-free vs. ethanol E10 respectively.

I realize that there could be other, externalities that influence my observations - my numbers have been developed over what I believe is a statically-significant number of miles and I am aware of systematic errors from odometers and have calibrated these errors against my GPS.

I have not observed a difference between the ethanol bearing 91 vs. 93 octanes - but I have not been as systematic about that.

This became acute on my truck 99 F-250, that does not get much use. Developed a leak in a fuel line - corroded through from the inside - in a steel line that runs from the tank to the engine compartment - the fix was $500! Mechanic attributed it to sitting around with ethanol-bearing fuel in the tank. Now its no-ethanol only for this truck plus some fuel stabilizer.

It's also ethanol only, when practical for my Cooper now. I drive it enough that a few tanks full of E10 now and then will be OK.

The title of this thread includes the term HP. HP is sort of an elusive quantity, the maximum HP occurs in a seldom used part of the operating spectrum for the car - that is, briefly and a narrow range, very high rpm. HP may be a measure of something but it does not correlate well with everyday driving. It does correlate well with drag racing success.

The merits of corn-based ethanol as a motor fuel is a rich topic for scientific and political debate. I don't think this is the place to get into those discussions.

Anyone want to share any ethanol observations - don't know if others are interested but I am. Thanks.

 

Thanks Slave to Felines, I won't go under 91. On purpose anyway. Between my wife and daughters and myself we have 4 cars. I put gas in all of them. THeirs don't need 91 so I use 87. So I still have to think about putting 91 in Comet. The habit of using 87 is hard to break when you still do it.

 

This seems to be the case and if the Wikipedia is correct, your fuel economy reduction is quite possible:

 

1. You think lower octane fuel means lower HP.
2. You think it should be ok to run lower octane fuel in a car rated for higher octane.

You really should do some more research on the subject if you believe the above statements.

 

Been using 87 in Desmond since day 1. AVG MPG on paper is 33.5 combined. I see no reason to use premium in a Justa.