the101dragons

Is there really a benefit to putting premium in the C class other then maybe the c230 kompressor. I really see no benefit and a waste of money putting in 91 when I could put in 89. It's not the money your saving but it's the purpose. There's no proven benefit on this is there. Here in Denver you can get really carried away and put in less octane due to less air too.

I'd have to agree with cigalert on the tahoe thing and it apply's to these C classes as well.

drexappeal

ct, of course! Hey, it's been a while since a newbie tried to call me out. In fact, I think the last time was when I wasn't even a moderator yet.

BTW, this is off topic, how is that D.I.Y. comin' a long on that new gizmo you got?

ctC230K

which one, the LED signal lights and side markers or the sprint booster? haha... i've been slacking. i got all the photos just need to upload them.

drexappeal

Sprint booster, but didn't know you were gonna D.I.Y. the LED signal lights. Nice. Either way, can't believe you're slacking! Usually, those pics are up with the quickness once you've taken them...LOL.

Make sure to do the LED signals D.I.Y. in a separate thread, so I can add it to the sticky later on.

skr

There is a benefit to putting 91 in your car. When you see & read all the reports saying there is no benefit to putting in anything more than 87 in most cars, they are correct. But modern MB's do not fall in that category. Although you can put in less than 91, and cars computer will adjust its settings accordingly, so you won't hear knocking, you are hindering the engines performance & fuel efficiency. For "most" cars 87 is what the manufactures design the car to run with, so putting in anything higher (without modifying the ECU), is a waste of money.

I guess if you bought your MB, for looks & as a status symbol, you may not care about performance & preservation. However, if engineering & performance is also part of the reason you own a MB, then it makes no sense why you won't use the proper fuel it was designed to burn.

Sickwitit

Hey Vectorz chillout with the name calling you don't even know this Dude, but we all do his handle is Drexappeal and he is one of the most helpful dude's on this and or any board, members here have all at some point and time ask for and or recieved his help and opinions, and this is before he became a Mod.
So check yourself, Drex's a friend to the room, and welcome to the board, now read the rules and learn how to play with others.
Sorry guy's for going !
I use Sunoco and Exxson 93 for the most part, but I'm willing try Chevron 94.

drexappeal

I wonder how the difference in mixture is from other states that carry 93, cuz they only have 91 octane here in Cali. I'm sure it's been discussed somewhere here on the this thread.

From what I remember, there isn't much difference and the only reason Cali has 91 as the top octane (other than race gas) is because of emissions.

ps...thanks for the post 'bout me Sickwitit. Glad there are people that actually pay attention.

Sickwitit

No problem Drex!

the101dragons

Drex

Here in Colorado we only carry 91 then 87 then 85.

I don't now where we are getting the benz cars engines are more advance then others. Compression in c classs are still 10 range except c230.

drexappeal

Wow, that's a strange range also. I've never really reasearched the differences in octane #'s that are used from state-to-state, but I've always known that different states have different #octanes.

If anybody has some information online that they could share regarding "why" there are different octane levels from one state to another, would you post the info?

skr

the101dragons,

Apparantly altitude does have an effect on octane requirements, so where you live in Colorado more than 91 would be useless. The following was taken from Wikipedia:

Using high octane fuel for an engine makes a difference when the engine is producing its maximum power. This will occur when the intake manifold has no air restriction and is running at minimum vacuum. Depending on the engine design, this particular circumstance can be anywhere along the RPM range, but is usually easy to pin-point if you can examine a print-out of the power-output (torque values) of an engine. On a typical high-rev'ving motorcycle engine, for example, the maximum power occurs at a point where the movements of the intake and exhaust valves are timed in such a way to maximize the compression loading of the cylinder; although the cylinder is already rising at the time the intake valve closes, the forward speed of the charge coming into the cylinder is high enough to continue to load the air-fuel mixture in.

When this occurs, if a fuel with below recommended octane is used, then the engine will knock. Modern engines have anti-knock provisions built into the control systems and this is usually achieved by dynamically de-tuning the engine while under load by increasing the fuel-air mixture and retarding the spark. Here is a white paper that gives an example: [3] . In this example the engine maximum power is reduced by about 4% with a fuel switch from 93 to 91 octane (11 hp, from 291 to 280 hp). If the engine is being run below maximum load then the difference in octane will have even less effect. The example cited does not indicate at what elevation the test is being conducted or what the barometric pressure is. For each 1000 feet of altitude the atmospheric pressure will drop by a little less than 1 inHg (11 kPa/km). An engine that might require 93 octane at sea level may perform at maximum on a fuel rated at 91 octane if the elevation is over, say, 1000 feet. See also the APC article.

for full article: http://en.wikipedia.org/wiki/Octane_rating

ctC230K

all gas stations i've used in the tri-state area have 87/89 then either 91 or 93.

jskip27

I have tried 87 and also tried tanks on 93 but I run usually one tank a month on 93 and the others on 87. I have not had any problems or check engine signals yet.

valdes

in florida it is 3.07 during the hurricane i paid 3.99 because it was the only station that had it and it was full service

BavarianPride

next thing you know they'll ask if it is ok to put in the "cheap" oil.
'cause it won't harm "MY" engine. Yeah right !
Ever wonder how most fat people got fat?
Not over night, for sure.
One ring ding at a time......... it'll eventually happen. Read the label.
Peace

IsaacRN

after reading through this thread i have a question. Previously the highest Octaine i could use was 91. I just moved and found that 93 is the highest. Reading in this thread people are talking about having their computers changed to reflect the different octaine reading. Why is that necessary and what will happen if the computer isnt told that the engine is receiving 93 octaine. Premium is Premium no? as far as the computer is concerned?

BleedzMerc

The octane rating describes how much compression is required to ignite a volume of air+gasoline without ignition. Therefore with the application of a 93 octane rating the gas is less like to ignite before it is fully compressed by the piston. This will ensure the cylinder reaches the full "stroke." ...in essence more HORSEPOWER!


Hope that answers your q.

I use Chevron Supreme $2.99 (91 Octane) in the Bay Area!

ps. oh and the computer should adjust accordingly...why pay 30 grand for a car that would be so ignorant to this?

benzgrl

I always use 93 octane...however, it is usually from a Circle K, which is by my house.....I was reading about the Top Tier gasoline link someone posted and I am now wondering should I start using Texaco, SHell, etc?????

alpinweiss

I would highly recommend using one of the Top Tier brands (www.toptiergas.com). I noticed that Texaco is now also on the top tier list; so in the southwestern US, your choices are Chevron, Shell, Phillips, Conoco, and Texaco.

Again, Top Tier is not a measure of octane. It is a measure of cleanliness and additive content (especially detergents). This will keep your valves, fuel injectors, and other fuel system components cleaner, and less prone to trouble.

ctC230K

how is exxon-mobil not in that list?

IllogicalBeetle

This is a question for anyone who has had the octane setting changed through Star Diagnostics for a 230K. I always use 93. So, is it worthwhile to get that setting changed? Or do you not see a big change in performance? I read somewhere you will lose mpg to about 17/25 from stock 20/30. Is this acurate?

Edit: Am I stupid, or do I not see BP on the list either?

Pashap5

I always pump Sunoco Ultra 94, i have upped my fuel stage through the star diagnostic but this has to be done in conjuction with an air filter (ie ITG or K&N) to notice any difference..as far as the MPG is concerned i am not sure about your numbers but i really haven't noticed too much difference ever since...
good luck

ChaRgeC230

my mom pumped 89 into her ML and the check engine light came on and car started bogging... cost $510 at the dealer to clean out the gas tank.... so i always use 91 or up

rlee02135

i have the fuel setting.

Onizuka

I use 91 octane from Chevron, around 1.05 CAD/Liter
which is around 3.5usd/gallon Q_Q
sometimes I wish I live in the States