I'm planning my first true cross-country (and around the country) road trip this coming summer, and it looks like it's going to be around 8,000 miles or more. Being that the MINI is my first new car, I've babied it (not the throttle, just tried to treat it right) and so have been religious about using 93 octane. Obviously, I am curious about what affects running cheap gas for the road trip will have on the engine. I KNOW my wallet will appreciate it!

I know these cars were meant to run on anything, but will this have any permanent affect on the engine? Do I need to do anyhting differently? Asuage my fears!

 

I used 89 octane for a while during the humid part of the summer on the advise of my Serivce Advisor. I was having an issue with the car reving too high at start and stalling out. He indicated that many people were having the issue in my area due to the humidity. Switching did solve it, but as soon as the weather changed I went back to 93 octane as I find that overall the car runs better on it.

I recently did a trip DC to Boston 459.8 miles one way. Averaged 39.3 mpg over the trip.

 

...unless you drive an S or JCW. 93 octane is recommended, highly.

I average 29.4 with my 05 JCW driven gingerly. If I'm on it a lot, that number drops to between 26-27 mpg. Half city, half highway.

 

There are knock sensors, so no real worries, except the slight hit on performance. I used 89 constantly on my MC and it never suffered. I believe my final average when I let go of it was somewhere around 36MPG, but i'd have to look it up. My MCS gets 93 all the time because Sam's Clubs offer 93 octane for cheaper than most places sell 89.

 

Yeah, I forgot to mention that I drive an S

 

Let's assume a couple of things...

8,000 mile trip / 25 mpg = 320 gallons used

320 gallons X $1.85 per gallon (mid-grade gas) = $592.00 total for gas
320 gallons X $1.95 per gallon (hi-test gas) = $624.00 total for gas

Difference of $32.00

Is $32.00 worth the peace of mind to go ahead and fill up with 93 octane?

Is to me... :smile:

 

Your MINI is designed for premium fuel. There is a knock sensor which should modify the timing so that there is no damge o the engine from the pre-ignition that may occur while using the lower octane fuel. When the timing is retarded to prevent damage, both performance and economy will be negatively effected. Depending on the amount that your fuel mileage drops, it could actually cost you more to use the cheaper fuel. It is probably best not to second-guess the engineers that designed your engine.

 

Wow. Here in the north east, $1.95 is a good price for 89 octane. 93 is around $2.15. But it's a good point.

[QUOTE=Rev. Limiter]Let's assume a couple of things...

320 gallons X $1.85 per gallon (mid-grade gas) = $592.00 total for gas
320 gallons X $1.95 per gallon (hi-test gas) = $624.00 total for gas

Difference of $32.00