Well, I wasn't in the neighborhood of my usual gas station where premium sells for 10 cents a gallon over regular.

So for the first time ever in a MB owned car, I opted for mid-grade.

Even though we have some of the cheapest prices in the country for gas, I just couldn't pay $2.17 a gallon for premium.

We'll see how it goes. Typically I get between 19 and 20 mpg in my mixed driving week.

1989 300e 151k miles.

Depends on the engine. My 260E with 9.0 CR runs just fine on regular. Has for years. With higher CR or maybe super/turbocharged, it might matter. then again, most of theose engines have knock sensors. you'll never notice a difference.

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Norm in NJ
Next oil change at 230,000miles

KE-equipped engines of that era don't have knock sensors. Most will run on regular unleaded without detonation, especially in cool weather and coolant temperatures below 90C. In warmer temperatures or at higher coolant temperatures there may be some transient detonation at low revs/high load.

The specified CR of M103s in US models is 9.2:1.

Duke

$2.17 for premium would look good here in Oregon. That's about what we pay for regular and premium is up around $2.39. I'm also thinking about using a lower octane fuel around town.

You're more likely to get detonation "around town" than at highway speed including passing, since "around town" is when the engine is most likely to see the low rev/high load condition and higher coolant temperatures, which are the most likely conditions for detonation.

Duke

And we have it good here in the U.S. I've been in the UK on business a couple of times this year. On the way to a customer visit we stopped to fill up my coworker's car - a BMW 320D. Diesel was 95 pence per liter - the tab came to 14 Pounds for 15 liters. Thats about $28 for 4 gallons of fuel! A full tank costs almost $100.

On the plus side, a 3-series with a modern common rail diesel has surprisingly good performance and delivers better than 40MPG on the motorway.

- JimY

i have been paying around 2.59/gallon of premium lately.

last tank cost me close to 60 bucks. i think it was ~57 and change.

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Jonathan
1998 S600
2001 E430
1994 E320
1991 560SEL
1994 Turbo R

$0.10 per GALLON difference? We pay 12 cents per LITRE more for premium, which is about 45 cents per gallon.

Is this false economy? How much money are you going to save? Gasoline is not a major cost of operating a car. Depreciation is king!

Okay, suppose you drive 15,000 miles per year and get 20mpg. You burn 750 gallons of gas per year. That 10 cents difference adds up to a total of $75.00 PER YEAR or about $6.25 per month.

SIX BUCKS a month you're trying to save. Don't stop at StarBucks tomorrow.

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John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

I run midgrade in the winter. No troubles.

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1986 300E 5-Speed 240k mi.

$2.17 for premium is a real good price! I think it is in the $2.30 range up hear.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Not to hijack this thread, but..... premium here is over $2.50 a gallon. Marathon's refinery is here - not 4 miles from my house.