What kind of Octane do you put in your C-Class?
06-24-2005, 02:32 PM
#226
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Originally Posted by Spyke
One of the problems in these discussions is terminology. To me, if the mixture doesn't combust when it is supposed to you have a mis-fire. If it ignites before it is supposed to, you have pre-ignition. The octane rating of the gas isn't relevant to either. I have no idea what people mean by "pre-detonation"? There is pre-ignition, and there is detonation, but they are different events. "Pre-detonation" would seem to apply to the period before detonation occurs, which would in most cases mean normal combustion.
Anyway, pre-ignition is caused by a hot spot in the cylinder igniting the mixture before the plug fires. It is caused by a physical fault in the combustion chamber; a sharp edge, an exposed thread on the plug, a carbon deposit, whatever. You really need to address this fault to fix the problem, going to a higher octane gas isn't the correct answer here.
Detonation occurs when the unburned mixture in the cylinder auto-ignites/explodes/detonates as a result of the temp and pressure in the cylinder. There are numerous ways to fight this, one of them being using a gas that resists detonation longer, i.e. has a higher octane rating.
Pre-ignition may lead to detonation, but they are not the same thing. You can have one without the other.
Anyway, pre-ignition is caused by a hot spot in the cylinder igniting the mixture before the plug fires. It is caused by a physical fault in the combustion chamber; a sharp edge, an exposed thread on the plug, a carbon deposit, whatever. You really need to address this fault to fix the problem, going to a higher octane gas isn't the correct answer here.
Detonation occurs when the unburned mixture in the cylinder auto-ignites/explodes/detonates as a result of the temp and pressure in the cylinder. There are numerous ways to fight this, one of them being using a gas that resists detonation longer, i.e. has a higher octane rating.
Pre-ignition may lead to detonation, but they are not the same thing. You can have one without the other.
There is really no band-aid cure for a broken or bad design.
06-24-2005, 03:50 PM
#227
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2003 C230K Sport Coupe, 1986 190E 2.3
Originally Posted by Spyke
One of the problems in these discussions is terminology. To me, if the mixture doesn't combust when it is supposed to you have a mis-fire. If it ignites before it is supposed to, you have pre-ignition. The octane rating of the gas isn't relevant to either. I have no idea what people mean by "pre-detonation"? There is pre-ignition, and there is detonation, but they are different events. "Pre-detonation" would seem to apply to the period before detonation occurs, which would in most cases mean normal combustion.
Anyway, pre-ignition is caused by a hot spot in the cylinder igniting the mixture before the plug fires. It is caused by a physical fault in the combustion chamber; a sharp edge, an exposed thread on the plug, a carbon deposit, whatever. You really need to address this fault to fix the problem, going to a higher octane gas isn't the correct answer here.
Detonation occurs when the unburned mixture in the cylinder auto-ignites/explodes/detonates as a result of the temp and pressure in the cylinder. There are numerous ways to fight this, one of them being using a gas that resists detonation longer, i.e. has a higher octane rating.
Pre-ignition may lead to detonation, but they are not the same thing. You can have one without the other.
EDIT: I re-read some of the replies here and I'm wondering if some people aren't envisioning a running engine as a series of explosions in the cylinders? That's not what's going on. In normal combustion, there is a flame front. The fuel actually does burn (rapidly) rather than explode. When the mixture detonates, the is no flame front, just BOOM. Many engine texts have pictures of normal combustion vs detonation - you can easily see the difference.
Regarding an earlier post - not only does light knock not harm an engine, it can actually increase power. I think VW published an SAE paper on this back in the late '70s, early '80s??? The problem is, who defines what "light" knock is, and how do you control it so it never becomes not-so-light knock?
Anyway, pre-ignition is caused by a hot spot in the cylinder igniting the mixture before the plug fires. It is caused by a physical fault in the combustion chamber; a sharp edge, an exposed thread on the plug, a carbon deposit, whatever. You really need to address this fault to fix the problem, going to a higher octane gas isn't the correct answer here.
Detonation occurs when the unburned mixture in the cylinder auto-ignites/explodes/detonates as a result of the temp and pressure in the cylinder. There are numerous ways to fight this, one of them being using a gas that resists detonation longer, i.e. has a higher octane rating.
Pre-ignition may lead to detonation, but they are not the same thing. You can have one without the other.
EDIT: I re-read some of the replies here and I'm wondering if some people aren't envisioning a running engine as a series of explosions in the cylinders? That's not what's going on. In normal combustion, there is a flame front. The fuel actually does burn (rapidly) rather than explode. When the mixture detonates, the is no flame front, just BOOM. Many engine texts have pictures of normal combustion vs detonation - you can easily see the difference.
Regarding an earlier post - not only does light knock not harm an engine, it can actually increase power. I think VW published an SAE paper on this back in the late '70s, early '80s??? The problem is, who defines what "light" knock is, and how do you control it so it never becomes not-so-light knock?
Remember not everyone knows all the terminology, but most know what a PING is! Well unless they are avid golfers and think we are talking clubs!
06-24-2005, 05:57 PM
#228
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Originally Posted by mctwin2kman
...BS means nothing to the cheap person who does not want to put the proper fuel in the tank that the Designer of the engine specified for it to run at its most efficient point.
The Internet (esp. this forum) is a great source of information. It can also be a great source of mis-information if you don't know how to validate it. Too often, people reply with great conviction, information that is totally false!
Greg
06-24-2005, 07:14 PM
#229
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1959 220S / 1979 230 G / 2002 A210 AMG / 2003 C320 SC / 2004.5 C320 SS / 2005 ML350 SE / 2008 smart
notice, how the idiot who always starts these stupid threads ends up being banned !!
nicedeboy / rockintunes23 / c230_617 / benzpro230 / benzset / knowalotaboutMB / lookinforbenzpart / amgpimps / cklass_balla / Needing2KnowDud / from190e_cs / benzgame / newbenzamg / and the list continues....
all the same person !
and he's got about another 6 or 7 aliases going on right now throughout MBWorld.
I still don't understand why the MODS do not ban him completely ???? Hello ?
I really don't care, and once he pops up again, I just put him on ignore, but it really doesn't contribute much at all to the forum, and just gets people fighting with each other about fuel octane levels, replacing Bi-X with or without bumper removal, C240 vs Mazda3, Hamster-Love, what wheels suck and which ones don't, etc... etc... etc...
nicedeboy / rockintunes23 / c230_617 / benzpro230 / benzset / knowalotaboutMB / lookinforbenzpart / amgpimps / cklass_balla / Needing2KnowDud / from190e_cs / benzgame / newbenzamg / and the list continues....
all the same person !
and he's got about another 6 or 7 aliases going on right now throughout MBWorld.
I still don't understand why the MODS do not ban him completely ???? Hello ?
I really don't care, and once he pops up again, I just put him on ignore, but it really doesn't contribute much at all to the forum, and just gets people fighting with each other about fuel octane levels, replacing Bi-X with or without bumper removal, C240 vs Mazda3, Hamster-Love, what wheels suck and which ones don't, etc... etc... etc...
06-24-2005, 08:18 PM
#230
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2001 E320 (210.065), Brilliant Silver; 2002 Ducati ST-2, Arrest-me Red
How did this worthless post
get to be this long? 
For all of you that don't want to put in the octane rated fuel for which the engine was designed, shame on you.
Particularly when your justification is that you just leased it anyway. That is simply 
And for those of you with the chutzpah to actually recommend that others follow your horrible example, Dante has a special section of H E double L :v set aside for you.
Good grief, if you want to pump less expensive gas, then go buy a Taurus or a Malibu, don't take your cheapness out on your car. Didn't your parents teach you to take proper care of things? That includes nice things, too. 
For all of you that don't want to put in the octane rated fuel for which the engine was designed, shame on you.
Particularly when your justification is that you just leased it anyway. That is simply And for those of you with the chutzpah to actually recommend that others follow your horrible example, Dante has a special section of H E double L :v set aside for you.
Good grief, if you want to pump less expensive gas, then go buy a Taurus or a Malibu, don't take your cheapness out on your car. Didn't your parents teach you to take proper care of things? That includes nice things, too.
Last edited by Gregs210; 06-24-2005 at 08:52 PM.
08-11-2005, 02:10 PM
#232
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2006 c230 premium or plus gasoline
In my comparing the 05/06 I know the supercharger needs Premium gas.
But does anyone know if the 2006 v6 HAS to use preium or supreme gasoline? or will the Plus or midgrade be fine...
If so, what negatives, if any as a result of using the Plus gasoline on the v6.
Thx
But does anyone know if the 2006 v6 HAS to use preium or supreme gasoline? or will the Plus or midgrade be fine...
If so, what negatives, if any as a result of using the Plus gasoline on the v6.
Thx
08-11-2005, 02:17 PM
#233
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1959 220S / 1979 230 G / 2002 A210 AMG / 2003 C320 SC / 2004.5 C320 SS / 2005 ML350 SE / 2008 smart
it's NOT the supercharger that needs premium gas,
it's the engine. V6 or not.
it's the engine. V6 or not.
08-11-2005, 02:48 PM
#235
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I haven't seen a Mercedes yet that doesn't call for premium fuel. This topic has been beat to death. Run less than optimum octane rated fuel and your engine wil compensate. Performance and fuel economy will suffer as a result but if you drivey like my 101 year old grandmother, you won't notice. Drive like Tony Stewart and you'll feel it. Run more than optimum octane rated fuel and NOTHING will happen except your wallet will be empty sooner.
08-11-2005, 03:15 PM
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2003 C230K Sport Coupe, 1986 190E 2.3
Originally Posted by E55AMG99
I haven't seen a Mercedes yet that doesn't call for premium fuel. This topic has been beat to death. Run less than optimum octane rated fuel and your engine wil compensate. Performance and fuel economy will suffer as a result but if you drivey like my 101 year old grandmother, you won't notice. Drive like Tony Stewart and you'll feel it. Run more than optimum octane rated fuel and NOTHING will happen except your wallet will be empty sooner.
But it has an 8:1 compression ratio. The year's after the 1986 I have did though. Pretty much any motor since the Mid-80's for MB has needed Premium.
08-12-2005, 12:42 AM
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Then I think the 2005 might be the car to get as the gas mileage is better. The v6 being slightly less frugal with the poorer gas mileage and the premium gas makes the 2005 make more sense.
08-12-2005, 12:46 AM
#238
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It needs premium because of the way it's tuned. If this bothers you and you are willing to compromise performance, explain this to your dealer, they can set options with their Star Diagnostic computer that was designed for countries where premium fuel is just not available, they can set it run on whatever you want. I tried this for fun once as it was believed to be a magic hidden performance bullet but lost as much as 17RWHP on the dyno set to what appeared to be the setting that would have worked best with regular.
Personally, gas can't be too expensive, I like it that way, keeps poor people off my roads, my taxes paid for them, not the poor people's welfare and food stamps. As a side benefit, it make people think twice about buying a mega-SUV, even with 10-15K off and make manufaturers leary about inventing new ones know they can't sell as many.
Personally, gas can't be too expensive, I like it that way, keeps poor people off my roads, my taxes paid for them, not the poor people's welfare and food stamps. As a side benefit, it make people think twice about buying a mega-SUV, even with 10-15K off and make manufaturers leary about inventing new ones know they can't sell as many.
08-12-2005, 12:55 AM
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wow. that was one fast response. Coincidence or else people live on this thing j/k.
I dont know a lot of about internals, just cars in general and makes/models/specs etc
Anyways, thx
I dont know a lot of about internals, just cars in general and makes/models/specs etc
Anyways, thx
Last edited by blk900t; 08-12-2005 at 01:04 AM.
08-12-2005, 01:09 AM
#240
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2005 C320wz
let's say you drive 13,000 miles a year and decide to use regular gas instead of premium gas and premium gas costs 20 cents/gallon more than regular gas.
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
$123 saved is nothing compared to the costs of tire and brake pad replacements. Even Service A would cost more than double of that
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
$123 saved is nothing compared to the costs of tire and brake pad replacements. Even Service A would cost more than double of that
08-12-2005, 01:28 AM
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Excellent point. It's all really kind of moot and irrelevant when you put it in Math.
I'm just thinking to myself, if the supercharger is such a great thing, then why did MB feel fit to discontinue it... possibly b/c; not as "refined", customer expectation a v6 should be in a benz, longterm reliability, less noisy, to have better freeway cruising? I guess they thought better to do so..
I'm just thinking to myself, if the supercharger is such a great thing, then why did MB feel fit to discontinue it... possibly b/c; not as "refined", customer expectation a v6 should be in a benz, longterm reliability, less noisy, to have better freeway cruising? I guess they thought better to do so..
Last edited by blk900t; 08-12-2005 at 01:46 AM.
08-12-2005, 08:51 AM
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2003 C230K Sport Coupe, 1986 190E 2.3
Originally Posted by mick1
let's say you drive 13,000 miles a year and decide to use regular gas instead of premium gas and premium gas costs 20 cents/gallon more than regular gas.
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
$123 saved is nothing compared to the costs of tire and brake pad replacements. Even Service A would cost more than double of that
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
$123 saved is nothing compared to the costs of tire and brake pad replacements. Even Service A would cost more than double of that
08-12-2005, 10:48 AM
#243
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Originally Posted by mick1
let's say you drive 13,000 miles a year and decide to use regular gas instead of premium gas and premium gas costs 20 cents/gallon more than regular gas.
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
08-12-2005, 11:13 AM
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It's a pay me now versus pay me later type thing.
All valid points...do the math and it will come out the same.
Would you buy the cheap oil that's $1.50 less per quart and put in there? No.
Would you buy the cheap beer that's $3.00 less a six pack? No.
I'm rambling, put what you want in there and insert your credit card in the fuel pump and watch it roll over waaaaaaaaay too high.
All valid points...do the math and it will come out the same.
Would you buy the cheap oil that's $1.50 less per quart and put in there? No.
Would you buy the cheap beer that's $3.00 less a six pack? No.
I'm rambling, put what you want in there and insert your credit card in the fuel pump and watch it roll over waaaaaaaaay too high.
08-12-2005, 11:13 AM
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bike
Originally Posted by blk900t
Excellent point. It's all really kind of moot and irrelevant when you put it in Math.
I'm just thinking to myself, if the supercharger is such a great thing, then why did MB feel fit to discontinue it... possibly b/c; not as "refined", customer expectation a v6 should be in a benz, longterm reliability, less noisy, to have better freeway cruising? I guess they thought better to do so..
I'm just thinking to myself, if the supercharger is such a great thing, then why did MB feel fit to discontinue it... possibly b/c; not as "refined", customer expectation a v6 should be in a benz, longterm reliability, less noisy, to have better freeway cruising? I guess they thought better to do so..
Anyways, if you wanna save money on gas...consider a hybrid engine vehicle
08-12-2005, 11:46 AM
#246
Originally Posted by blk900t
I'm just thinking to myself, if the supercharger is such a great thing, then why did MB feel fit to discontinue it... possibly b/c; not as "refined", customer expectation a v6 should be in a benz, longterm reliability, less noisy, to have better freeway cruising? I guess they thought better to do so..
08-13-2005, 12:32 AM
#247
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2002 C230 Coupe(M111)
Originally Posted by mick1
let's say you drive 13,000 miles a year and decide to use regular gas instead of premium gas and premium gas costs 20 cents/gallon more than regular gas.
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
$123 saved is nothing compared to the costs of tire and brake pad replacements. Even Service A would cost more than double of that
suppose your car gets 21 mpg like mine does.
13,000 miles / 21 mpg = 619 gallons of gas needed in a year
20 cents/gallon x 619 gallons = $123 saved a year.
$123 saved is nothing compared to the costs of tire and brake pad replacements. Even Service A would cost more than double of that
If I posted a mod that you could do or bolt on to your car that would give you 20HP for 123bucks, people would go nuts. For 123bucks, I'll take the performance.
BTW, 21MPG, that's pretty low for the 1.8, eh? My 2.3 gets always better than 24 in the city, over 30 on my 50/50 work commute loop.
08-13-2005, 12:34 AM
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2002 C230 Coupe(M111)
Originally Posted by MB-BOB
The use of superchargers on MB passenger cars has largely been an EXCEPTION, not the rule. So, to see them go over time is not a big development.
They will be back. If not, then Turbo's for sure. That C230 V6 is pretty weak for a 6 by today's standards. A Chevy impala with the base PUSHROD motor makes more HP and Torque.
08-13-2005, 12:36 AM
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2002 C230 Coupe(M111)
Originally Posted by revstriker
And of course, if you drop even 1 mile to the gallon with regular gas (compared to premium), you end up purchasing 31 gallons more using regular gas. That's going to eat into the $123 savings as well.
08-13-2005, 12:12 PM
#250
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Originally Posted by Outland
Logically, there's no reason you would use more gas. Octane is measurement of how well a fuel can resist detonation, not how much energy is in it.
