Has anyone noticed a difference in gas milage with 92 octane, compared to 87?

 

Yeah I know the lower psi isn't helping. I'll have to recalculate once I get the kumhos on this week.

I'm considering getting the dtbv.

 

Why would you run 87 octane? These cars are designed for 91 octane - atleast the S is.

I use 93 octane because that's what shell has.
Higher octane, I believe, is supposed to net a higher mpg...

 

91 octane, according to the 2003 S and Non-S manual, is required.
"FUEL SPECIFICATIONS The engine uses lead-free gasoline only. Required fuel: Premium Unleaded Gasoline, min. 91 AKI. AKI = Anti Knock Index." http://www.motoringfile.com/files/20...perCooperS.pdf
Using anything lower can cause engine ping and may reduce MPG. The on-board computer will actually retard your timings to handle the low octane gas, but this can reduce performance and MPG. Engine ping from low octane fuel is probably a lot less common in non-S Cooper, especially if the car isn't driven hard.

Using octane higher than 91 shouldn't really affect MPG. Higher octane does not have more 'bang'; it requires more heat to detonate the gas, preventing engine ping in high-compression and high performing engines.

 

The short answer is "no". The longer answer is: if it did, it was negligible and lost among other minor factors in tank-to-tank MPGs such as type of driving that week, or how much I had my bike on the roof, or how much i ran the AC etc...

I've been tracking my MPGs since I got the car last June. I was using 91 or better until the price went north of $3.50 a gallon. (It was under $3.10/gal for the first several months).

Since then, I've been trying different octane ratings. I notice it runs rougher on 87 (the lowest octane), but my subjective experience, as well as the MPGs are no different between mid-grade (89) and 91+.

Since i drive more than 30k miles a year, the cost difference between 89 and 91 octane is about $100 a year. If i noticed a difference, I might be able to say I was getting something for that $100, but since I don't, I'll spend the $100 on something else.

Recommended for the base, not required. (I don't know about the "s")

.

 

What does your owner's manual say? According to the 2003 S and Non-S owner's manual I'm looking at, it says:
"FUEL SPECIFICATIONS Required fuel: Premium Unleaded Gasoline, min. 91 AKI. AKI = Anti Knock Index."
http://www.motoringfile.com/files/20...perCooperS.pdf
I just checked the 2002 and 2004 manuals which state the same requirement.

 

I have been averaging about 240 to a tank. I have been kind of spritely on the freeway so I think I could get better.

 

Yeah, I was pretty sure both s and non-s require 91 octane but wasn't positive.

When I said higher octane nets higher mpg, I meant 91 as opposed to say 87...

 

You're right. I was speaking (or typing) from memory. Obviously, I was drawing on a different source in my head (I think it was a Car Talk article on octane in high-compression engines now that i think about it.)

This is good, as it has me re-thinking my attitude about what fuel i buy. Maybe it's the topic for another thread, but it raises questions such as what do they mean by "required", and what are the consequences for going with a lower octane?

I'll do a search and see if there's already a discussion going or (or concluded) on the topic.

 

Generally speaking, going below the "required" octane with a modern, fuel-injected, computer-controlled engine will result in more tendency to ping/knock (detonation), which then gets detected by the ping/knock sensor and the computer backs off ignition timing to compensate. This results in less power and less MPG--usually to the tune of costing you more in gas money despite the slightly lower cost of the gas....

A dime per gallon at $3 is about 3.33%--6.66% if you step down two grades, and as the base price goes up, the % price difference between grades gets smaller, unless they increase the dime between grades to 12 or 15 cents....

HTH!

C ya,
Dutch

 

My original question about mileage was something that interests me because that may be the only downside result of useing 87 as opposed to 91. Here in south Florida the flat driving environment causes very little load on the engine.
I've been using 87 in all the cars and motorcycles I have, or had, over the past many years even though mostly all require premium fuel.
I don't know how this swap would work in more rugged driving environments, but for me cheaper gas seems to do the job.

 

I've had one tank of pure highway driving that got over 38mpg, but in general it's 33-34 even in summer since I never use the A/C, with a one-time low of 24 when I had a problem with a coolant leak. I use 93 gas.

 

Hey, where you at in SD? I've seen a blue checkmate driving around Escondido a few times....any chance you live in esco?

 

Have an 05 MSC with 38k running 93 octane all stock. Currently averaging a combine 27 MPG highway/city. I guess this is not to shaby for a sports car, but i came from a VW TDI with 43 MPG and 38 on the bad side, but u cant have both; Its either perfomance or economy, but i hear the new Mini's (turbo) are running about 34 MPG's.

 

i get about 290 on my full tank driving around in city and that is in socal, havent done the full tank on the freeway

 

I'm just jealous of your fuel prices...

I just read $3.60 for a gallon. That's 3.5 liters right?
I just paid €1.699 for a liter of 93 octane. That is $2.32 for a liter, so $8.17 for a gallon. Please stop complaining about fuel prices :(

My little car averages about 1:11.2 (l/km) which is about 24MPG if I'm not mistaken. We drive just over 2000miles per month with it. That's $660 per month in fuel costs!
The insurance however is $40 per month for all-risk

 

Ah, but things are closer together on your side of the pond, so that evens it out a bit--not to mention that you have cooler stuff there than we do here in the United States of Generica....

C ya,
Dutch

 

1 US gallon = 3.785L
1 Imp gallon = 4.546L

11.2km/1L = 42.39 km or 26.18 miles/US gallon

Yes, gas is cheaper here but it can be cheaper. Don't forget that American peeps (tax-payers) have to fork over $700 billion per year to protect the Mideast oil supply... which of course makes porn0graphic amount of profit for the oil companies. So if you divide $700b into 309 million people, that's an extra $2265 per American per year. Of course not all 309 million US peeps have cars so it's actually much higher than that.

I don't know why we don't go the obvious route and invade Canada which has loads of natural resource.... they're very peaceful and they're right next door!!! Quebec has already signed up for this idea. And I'm sure we can make Jim Carey & Justin Bieber the puppet Prez and V.Prez.

 

I would go so far as to say we set Quebec up as the new D.C., and get behind them 110% in invading and subjugating the Great White North, and making French the official language of the new United State of Quebec....

C ya,
Dutch

 

Celine Dion is up for singing the anthem... "Oh Canada... Oui America"

 

My 2003 S consistently averages around 28 mpg, and I've been running the low octane (although I will probably upgrade now having read this). I don't baby it, but I don't play Gran Turismo in it either...kind of shocked at the low mpg's some of the other drivers are getting...

 

We had a prime minister (something like your president) whom upped the price of gasoline and petrol by €0,25 a few years ago. Our gas prices are 70% tax...

Oh and we have a special tax on cars called BPM. A stock 2011 Mini Cooper S Chili would cost you just over $46.000 without delivery costs. That would add about $1300 (€1000). This is without any options, not even metallic paint.
How much is that in the US?

Oh and I pay 52% income tax, our sales tax is 19%. My mortgage-percentage is 4.3% which is considered really cheap... But we do have healthcare, costs me about €90/month

 

where are you driving at? i dunno but here in LA i got about 290 on full tank in city, kind of low ehh

 

You must be going down hill both ways to work and back!!!

 

Well, I do live in Kansas, and it's kinda flat here...