For the 73 280SEL 4.5 and the 79 6.9 I use regular
For the 97 E420 I use premium because it's a higher compression engine.

I was under the impression that most gas stations regardless of what banner they fly under get gas from the same 4-5 suppliers.

I was also under the impression that higher octane premium gas does not detonate as quickly as regular, which would cause pinging in a high compression engine. Premium gas should not offer any additional value in a low compression engine.

I normally get my gas from Citco because it's the closest one to me, there is a QT nearby but 1/2 the CC readers don't work on it and they never post signs to tell you that the readers are broken which causes me to get very frustrated

__________________
With best regards

Al

definately depends on the model for octane needs

the way the gas works as i have heard it told, is it all is basically the same liquid fuel, but different companies have their specific additive packages, cleaners octane etc that is added to the fuel they sell.
we have a customer at the shop where i work, he owns several Arco gastations here in southern California (known as very cheap gas), all he ever used was the high octane arco fuel, one day his car was towed in for a no start condition, when we tried to start it the engine sounded as if it had no compression, there was so much carbon accumulated on the valves that they were being heald open not allowing compression to build. since then all he uses a (gas station owner)is chevron high octane with techron. been several years without any more problems.

Is there any automotive fluid that hasn't been polled in this forum more often than gasoline? I only hope that the original poster took the time to search before putting this old nugget out again.

Is this octane measured the same as in the US? There's "Research" octane and "Method" octane. Octane in the US is measured as (R+M)/2.

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95 E320 Cabriolet, 159K

Alabbasi, I had been told that QT gas is awful, but ran several cars on it for several years, with no ill effects. I do like the 59cent fountain drinks during the summer...

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2002 Ford ZX2
2 x 2013 Honda Civics

Typically we run plain old 87 octane regular in both our 300Es and have for years. Sometimes we splurge and put in half 87 and half 93. No particular brand...just wherever the price is lower. I don't buy where the prices are higher, since I don't believe in feeding the hand that bites me.

I figure we've saved about $2500 on the difference between regular and premium, per car, over the years.

Both cars still run great, in spite of this "mistreatment."

BTW, I'm impressed with the placebo effect of that 105 octane miracle fuel mentioned above.

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2012 E350
2006 Callaway SC560

I run Shell hightest in my 1990 420 SEL and it runs great with this gas.

It ran for about 5 minutes

__________________
With best regards

Al

My W201 runs best on Mid-Grade Exxon/Mobil Gas, it only requires regular but seems to run a hair smoother on the Mid. Runs a hair lumpy at idle on any other brand. My W203 gets Premium and runs the same on any brand used.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

I run cheap **** in the truck... God knows it uses it up quick enough.

I'm trying to blow it up, case in point...
http://img.photobucket.com/albums/v644/NathanEbert/ticket02.jpg
http://img.photobucket.com/albums/v644/NathanEbert/ticket02ETD.jpg

~Nate

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95 Honda Shadow ACE 1100.
1999 Plymouth Neon Expresso. 2.4 swap, 10.5 to 1 comp, big cams. Autocross time attack vehicle!
2012 Escape, 'hunter" (5 sp 4cyl)

Thanks for the link, carson356. Good info!

I usually use Sunoco Ultra 94.

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Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon

Nope, Europe uses only the higher research octance value (RON), whereas North America (and elsewhere?) uses the average.

http://en.wikipedia.org/wiki/Octane_rating