What kind of Octane do you put in your C-Class?
91 is going for about 2.13-ish here now... I would never put anything less than 91 in my car!
P.S.
Not every MB can use it. But it did provide for a nice tax break.
plus 91 octane and
premium 94 octane and up.
I use plus. The middle baby! Not as expensive as premium and not as chep as regular just in case. Oh and mine is a lease too. I put regular once in my coupe and the car was jumpy for some reason... did not feel as smooth or maybe it was all in my mind.
If something breaks due to natural occurrence they have no problem fixing it. If you break it and they can prove it... you pay for it. Just like if you never did an oil change and the motor seizes up. MB won’t fix that under the 50k.
If something breaks due to natural occurrence they have no problem fixing it. If you break it and they can prove it... you pay for it. Just like if you never did an oil change and the motor seizes up. MB won’t fix that under the 50k.
Basically octane is the breaking point of gas. A higher octane has less of a chance of detonation. (Gas combusting before it’s supposed to) the reason turbo and supercharged cars run high octane is to reduce the chance of detonation due to the large amount of air its forcing in to the chamber. Which is a lot worse then it would be for a naturally aspirated car. When your forcing air in to the cylinder and it ignites before it is meant to you have a bigger bang then an NA car and more of a chance to cause damage.
Much like you see people that up the boost on a turbo car will retard the timing to reduce the chance of detonation.
Last edited by from190e_cs; Jun 21, 2005 at 05:24 PM.
The Best of Mercedes & AMG
1.28 per fill up. // 16 gallons??
6.40 a month if you fill 5 times a month
in one year you save 76 dollars.
is it really worth it? 87 gas has a lot of bad things in it. People say its the same gas but i dont think its true. If you lease go right ahead. If you bought your car,just pump the 91.
FYI, while there might be major differences in how a supplier achieves 93 vs. 87 octane rating, both types of fuel still must meet the same minimum standards. The only bad thing about 87 is that it does not meet the minimum octane rating for your engine.
Okay, that's harsh. But there are two kinds of octane specs from manufacturers. There are those that *recommend* a higher octane, and in those cars the engine is designed for a lower octane (87 usually). However, the ECM will reconfigure ignition timing and fuel mixture to take advantage of higher octane fuels. In that case it doesn't really matter what octane fuel you put in the tank, although if you're looking for the highest performance you'll pump the higher grade.
However, the others "REQUIRE" a specific minimum octane; the engine and it's management systems are engineered and designed from the ground up with the idea that the minimum octane requirement will be used. That is what you are dealing with in the present case. If the engine specs 91 octane, you pay the premium. Even in places where the altitude permits 87 octane users to pump 85 (Colorado, for example) you STILL have to pump 91 octane.
What happens if you fail to use the required octane fuel? The BEST results you can expect (in addition to saving a couple of bucks per tank) are a reduction in performance and fuel economy as the feedback loops in the engine try to compensate. Pre-ignition, increased pollution, carbon build up, burned valves, clogged fuel injectors and a ruined engine are also likely results.
One question: you noted you're pumping 93 octane; if the car only requires 91 then you don't need to pump 93, so there's a place you can save a few cents per gallon.
Hey, I don't like it either; it is painful to see 85% of other drivers saving 20-25 cents per gallon. But then I sit in the nicest car I've ever owned and I figure, you know what? It's entirely worth it. Bring on the liquified dinosaurs as long as they last.

Take care and enjoy the ride,

Greg
But in your case......I would rather find some cheap gas station and put premium in it. Such as Costco and Sam's Club gas.
Your car will come haunt your in your dreams if you ever put anything less than a premium in the gas tank~ :v
Then you pump 91.
Cheap out on your date, not your ride. Or trade it on something that doesn't require 91.
Last edited by Gregs210; Jun 21, 2005 at 12:24 AM.
The alternative is do nothing, let the car ping and then the ECU will retard timing losing even more power. The only problem with that theory is when the ECU runs in open loop mode at idle and full throttle where it runs on a set program and doesn't respond to sensors because at those points they are not accurate, then you just ping and the worst thing that will happen is you may burn up valves, rings, nothing major, just keep the savings in a cookie jar to pay for repairs.
Then there's financial aspect of doing this but that can't be as important as the perceived money you are saving, after all, perception is reality. I would save about 6% for the cost to fill up my tank (in my area that's about $2.50 for regular and $2.65 for premium). Now imagine that the ECU has to protect the engine from damage so it retards timing and enriches air/fuel mix and that costs about 1.5 MPG so with premium I would average 25 mpg but with regular I would get 6% less mileage or 23.5 mpg so I would break even except I would likely get 10-15% less power so it's not something I would enjoy doing just to break even. Sure, certain days you will do better than a 6% loss when it's damp and cool out and some days when it's dry and warm you will do worse.
Dude, just buy 91 like you are suppose to...I tend to agree with what was said earlier now about not being able to afford the car. Yeah, 8 cents/gallon difference was tad low estimate...its usualy 20 cents here in GA as well. The equation still works and sorry saving a ~150bucks a year ain't worth the future headaches of early engine breakdown.






