Mercedes & Gasoline - Page 2 - PeachParts Mercedes-Benz Forum

brewtoo · #16 09-13-2007, 12:22 PM

Quote:

Originally Posted by juribe2

It's not about temperature. It's about compression. Higher octane means it needs more compression to ignite without a spark (pre-ignite).

Higher temperature is caused by Higher pressure. That's how diesel engines work.

They compress the fuel until it is hot enough to ignite. So really, it is about temperature.

Rockman59 · #17 09-14-2007, 11:58 AM

I have a 1986 560 SEL with 156K miles. This car has had nothing but regular unleaded fuel and it runs fine, gets decent mileage and has had no engine problems. That being said, if you drive your MB hard and fast or pull a trailer or do things that put the engine under heavy load, premium fuel is the way to go. But for normal everyday driving you can use regular unleaded.

dukegrad98 · #18 09-14-2007, 12:06 PM

Quote:

Originally Posted by brewtoo

Higher temperature is caused by Higher pressure. That's how diesel engines work.

They compress the fuel until it is hot enough to ignite. So really, it is about temperature.

Uh...don't think so... I believe only the air is compressed in a diesel, and then fuel is injected. In a gas engine, the air-fuel mixture is all compressed, then the spark plug fires. Someone correct me if I'm wrong, but I seem to recall this being one of the main differences between the two types of combustion and fuels.

Cheers, John

brewtoo · #19 09-14-2007, 12:25 PM

OK, I believe you've got me there.

The fuel is injected into the superheated air and Blam! It blows up real good.

RConrad · #20 09-15-2007, 11:15 AM

Good news/bad news guys, this may be hard to get your mind around about gas grades. High test fuel is actually dummed down regular, that is they put in additaves to keep your high compression engine from dieseling.
FYI

Ron

Rockman59 · #21 09-15-2007, 01:57 PM

High test fuel is actually dummed down regular, that is they put in additaves to keep your high compression engine from dieseling.
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Sounds to me like it is dumbed up......

neznaika · #22 09-22-2007, 06:37 PM

At least you guys weren't arguing too much.

I'll stick with Shell. I've already put Seafoam in my car, and ran in nonstop untill dry. I think mpg is a little better. The car runs just the same though. I never put 87 into it, and as far as I know, this C280 never seen regular in its tank. Anyone knows if Amoco adds any cleaners to its premium?

And, of course, thanks to everyone for the input!