Because of the turbo, is it a necessity to use the highest octane gas or is it alright to use the second highest. With increasing gas prices, wondering if mid grade is alright.

 

i always go the the highest available whether it be 91 or 93 even tho right on the in side of the gas lid it says it recommends 89 minimum (07 MCS) its not going to hurt to just go with the best grade and if its a .10 cent difference then it would only cost a difference of a whopping $1.30 to fill all the way up with premium compared to mid grade. it also doesnt hurt to through in some fuel additive every so many fill ups, less then $10 bucks at your local parts store and will help keep your system clean.

 

The turbo has nothing to do with the gas you use. There is not more energy in higher octane gas, it has to do with engine compression and pre-detonation. The lower the octane the less compression is needed to detonate the gas without a spark, which causes knocking.

 

Which is exactly why with boost you want to use the octane rating that your car is tuned for. The higher pressures from boost can make detonation a much worse thing than in naturally aspirated cars.

If you put lower octane fuel in your car, just don't ever floor it and you should be fine. I can't imagine the savings are worth it though, I drive my car hard and rarely see below 30mpg.

 

I have mine ordered and still waiting it to switch over to production status but it's good to get the most info. I just hope whenever I get it, gas doesn't increase by 7cents or more.

 

A Cooper S will run alright with regular, the engine has knock sensors, the computer will retard the ignition to prevent the engine from knocking. There will be noticeably less power. But I think it is worth the extra couple of bucks a tank to fill it up with high octane.

Dave