View Poll Results: Since gas is going up again.....what grade gas do you put in your C?
Always use regular unleaded
2
2.60%
Always use PLUS unleaded
1
1.30%
Always use PREMIUM unleaded
73
94.81%
Random...different grades at different times
1
1.30%
Voters: 77. You may not vote on this poll
what kinda gas do you put in your C?
07-16-2002, 10:45 AM
#51
Super Member
You guys are all messed up! I've never seen so much miss info! Here are some facts:
Detonation is the burning of fuel without an external ignition source, no spark. It is caused by either high temp, high pressure, or both. The higher the octane rating the higher the temp or pressure needed for the fuel to self ignite.
All octane ratings contain the same amount of energy from the same amount of fuel. Higher octane gas does not have more power than low octane under the same conditions. The power is gained from the higher compression allowed by the higher octane fuels ability to withstand higher P and T without self ignition.
All octanes burn at the same rate once ignited. High octane does not burn more slowly than low octane. Dual spark setups are for complete combustion of all the fuel in the cylinder and the power gain is due to burning all the fuel rather than letting some of it go unused. The swirl input is used to get a better mixture of air and fuel for more complete combustion.
Spark timing is a function of valve lift/timing and cylinder size aswell as the octane of the fuel.
Finally, if your engine does not detonate with 91 octane then higher octane wont make a difference that you will notice as our engines are not high enough compression to make the fuel self ignite and at the same CR a gallon of 100 octane produces the same power as 90 octane(as long as there is no detonation).
Detonation is the burning of fuel without an external ignition source, no spark. It is caused by either high temp, high pressure, or both. The higher the octane rating the higher the temp or pressure needed for the fuel to self ignite.
All octane ratings contain the same amount of energy from the same amount of fuel. Higher octane gas does not have more power than low octane under the same conditions. The power is gained from the higher compression allowed by the higher octane fuels ability to withstand higher P and T without self ignition.
All octanes burn at the same rate once ignited. High octane does not burn more slowly than low octane. Dual spark setups are for complete combustion of all the fuel in the cylinder and the power gain is due to burning all the fuel rather than letting some of it go unused. The swirl input is used to get a better mixture of air and fuel for more complete combustion.
Spark timing is a function of valve lift/timing and cylinder size aswell as the octane of the fuel.
Finally, if your engine does not detonate with 91 octane then higher octane wont make a difference that you will notice as our engines are not high enough compression to make the fuel self ignite and at the same CR a gallon of 100 octane produces the same power as 90 octane(as long as there is no detonation).
07-16-2002, 11:58 AM
#53
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2002 C230k
Originally posted by mdp c230k
You guys are all messed up! I've never seen so much miss info! Here are some facts:
SNIP
The higher the octane rating the higher the temp or pressure needed for the fuel to self ignite.
No... higher octane fuel will auto-ignite under the same temp/pressure conditions as lower octane, it just takes longer for it to happen. Check your sources. I've got Heisler's and Taylor's texts handy if you want quotes.
Dual spark setups are for complete combustion of all the fuel in the cylinder and the power gain is due to burning all the fuel rather than letting some of it go unused. The swirl input is used to get a better mixture of air and fuel for more complete combustion.
While providing a more complete combustion is one benefit, to say it's the only reason dual plugs are used is plain wrong. With two flame fronts there is no denying the mixture is going to be burned faster. Turbulent flow in the cylinder allows the flame front to be exposed to more volume of the mixture in the same amount of time. It burns the mixture faster and yes, more completely.
Both of these were originally brought up to demonstrate that the idea of a slower burning fuel contradicts known performance mods.
Spark timing is a function of valve lift/timing and cylinder size as well as the octane of the fuel.
While those are all factors in developing the optimum ignition map, actual spark timing (as opposed to optimum) is not a function of them. If I put in a different cam or bore the cylinder, the spark timing won't change. It will only change with octane if I'm not at the minimum requirements to begin with, so getting back to the original idea, going from 93 to 100 octane isn't going to change the spark timing on my C230. If we're going to list everything that can change the optimum settings, then your list needs to be longer. [/B]
You guys are all messed up! I've never seen so much miss info! Here are some facts:
SNIP
The higher the octane rating the higher the temp or pressure needed for the fuel to self ignite.
No... higher octane fuel will auto-ignite under the same temp/pressure conditions as lower octane, it just takes longer for it to happen. Check your sources. I've got Heisler's and Taylor's texts handy if you want quotes.
Dual spark setups are for complete combustion of all the fuel in the cylinder and the power gain is due to burning all the fuel rather than letting some of it go unused. The swirl input is used to get a better mixture of air and fuel for more complete combustion.
While providing a more complete combustion is one benefit, to say it's the only reason dual plugs are used is plain wrong. With two flame fronts there is no denying the mixture is going to be burned faster. Turbulent flow in the cylinder allows the flame front to be exposed to more volume of the mixture in the same amount of time. It burns the mixture faster and yes, more completely.
Both of these were originally brought up to demonstrate that the idea of a slower burning fuel contradicts known performance mods.
Spark timing is a function of valve lift/timing and cylinder size as well as the octane of the fuel.
While those are all factors in developing the optimum ignition map, actual spark timing (as opposed to optimum) is not a function of them. If I put in a different cam or bore the cylinder, the spark timing won't change. It will only change with octane if I'm not at the minimum requirements to begin with, so getting back to the original idea, going from 93 to 100 octane isn't going to change the spark timing on my C230. If we're going to list everything that can change the optimum settings, then your list needs to be longer. [/B]
07-16-2002, 12:28 PM
#54
Super Member
As I said before ALL octanes burn at the same rate once ignited. There is no slow burning gasoline. The difference is in resistance to self ignition. Yes, a dual spark setup will consume the same amount of fuel in less time due to two points of ignition but the fuel itself burns no faster. If two cars head toward eachother it will take less time than if one went to the other.
07-16-2002, 12:37 PM
#55
MBWorld Fanatic!
And what oil companies do you guys work for? I think that the extra placebo power created by 100 octane fuel is worth it to many people regardless of what goes on in the engine.
07-16-2002, 12:43 PM
#56
MBWorld Fanatic!
Dual Spark?
I read (can't remember where) that the W203 dual spark plug implementation works differently than we think. The plugs in each cylinder trade off on combustion cycles, they both do not fire in a timed sequence on the same cycle.
07-16-2002, 09:44 PM
#57
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2002 C230k
Originally posted by mdp c230k
As I said before ALL octanes burn at the same rate once ignited. There is no slow burning gasoline. The difference is in resistance to self ignition. Yes, a dual spark setup will consume the same amount of fuel in less time due to two points of ignition but the fuel itself burns no faster.
As I said before ALL octanes burn at the same rate once ignited. There is no slow burning gasoline. The difference is in resistance to self ignition. Yes, a dual spark setup will consume the same amount of fuel in less time due to two points of ignition but the fuel itself burns no faster.
Yes! I agree 100%! Nothing you've said here contradicts what I was saying...
And with that I truly will shut up now. :o
07-22-2002, 10:21 PM
#58
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w203 kompressor
allthis talk about gas makes me NEED this info from u guys:
what is the type of gasoline that you put in your car the most and don't start with the regulars -vs- premium... because we all should be using premium ONLY .
for those using anything less... you should be pouring strawberry-bannana-shakes in your tanks!!
charlie
for those using anything less... you should be pouring strawberry-bannana-shakes in your tanks!!
charlie
07-22-2002, 10:53 PM
#59
Here in St. Louis the only company on your list is Shell. I used Shell for the first 5000 miles and just swithced to Amoco. I read an article by a chemical engineer for one of the major oil companies and he said to change brands every 5000 miles. His reason is the additives in any brand of gas will eventually cause deposits to form in the fuel system. Additives from another brand will clean those up, but will form their own deposits later on. He said to use gas for any of the well known brands. The large brands sold here are Shell, Amoco, Mobil, and Phillips 66. Almost all of the gas, regardless of brand, comes from a Valvoline plant.
07-22-2002, 11:02 PM
#60
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C230 Sports Coupe
Me too Lynn. I switch it up between Amoco and Shell. Only 93 octane for me. With an occasional gallon or two of 103 octane
07-22-2002, 11:04 PM
#61
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w203 kompressor
lynn...
i like your info. you sound like you know what's up.
there so many diff. gasoline companies that sell gas that i can only list the ones that are here in the area. i trip out when i see an HEB or a SAFEWAY when i travel cause they have been long gone from this area for years. but i hear you about the switching of the petrol. nothing like the gathering of the dirt on your expensive toys right.
there so many diff. gasoline companies that sell gas that i can only list the ones that are here in the area. i trip out when i see an HEB or a SAFEWAY when i travel cause they have been long gone from this area for years. but i hear you about the switching of the petrol. nothing like the gathering of the dirt on your expensive toys right.
07-22-2002, 11:31 PM
#64
Former Vendor of MBWorld
Originally posted by MB-BOB
I can't vote either. I will report this problem to Mr. V.
I can't vote either. I will report this problem to Mr. V.
Good job man.
07-23-2002, 12:29 AM
#66
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w203 kompressor
o.k.
mobile is included and so is the other gasoline joint that the next person brings up. M-B Mob... here i was thinking you just didn't want to vote, boy was i wrong.you really do care about gas....gasoline that is!
mobile is included and so is the other gasoline joint that the next person brings up. M-B Mob... here i was thinking you just didn't want to vote, boy was i wrong.you really do care about gas....gasoline that is!
07-23-2002, 02:24 AM
#67
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C230 coupe 6sp
Chevron is recommended by Mercedes because of the Techron additive. It is only about 2 cents more than the cheap stuff (Quick Trip) here so I use it all the time.
07-23-2002, 06:11 AM
#69
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C230K Coupe/Orion/C4/C5/CD/AMG Spoiler/V60/TeleAid, 2 MGB's
I use Mobil Super + ....or Shell Premium if I need a 'touchless laser wash'. The stations are right across the street from each other and compete on price.
07-23-2002, 10:24 AM
#72
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2002 C240 6 spd manual
As an employee at one of the oil companies you listed I feel compelled to comment on the gasoline debate. Gasoline is a commodity, and as a result is the same from one company to the next. Exxon 93 octane is the same as Chevron 93 octane, etc. This allows for gas stations to exist where the oil companies infrastructure does not. The differentiating feature of gasoline is the additive package. Shell differs from Mobil from Diamond Shamrock, etc. 4 different brands may get their gasoline from the same terminal, with the blending of the additive package occuring just before the gasoline is loaded onto the truck. Hope this helps.
