until the end

Hi all i want to know what is the gasoline type and do you have problems ( knocking or smoke )
Im using 91 oct and i have knocking with bad smell and i used octan bosster wurth without any improvement
My car is c350 2009

MBRedux

Gasoline, like any product, can differ from brand to brand and by region. Shell gas sold in my region (Washington DC) will NOT be the same in another like Ky. They are regionally blended based on State to State code variances. I always use 93 Octane and never 91... and I switch between Shell and BP(Amoco) in my region. At the first sign of egg smelly gas, I go to another brand and refill to mix and dilute the trashy stuff as much as I can and NEVER return.

Try another make, and for Pete's sake, get rid of the octane booster... a total waste and tests have shown that repeated use can ruin engines, cats, and other components.

until the end

I use 95 oct from total and the result from the lab showed that it is 91.6 oct so i changed to golf and shell and the same result i have so i add the the oct boster and the knocking less but it still ther

TexFinn

When my wife fills the tank herself, she puts in regular (yeah yeah, I've tried talking sense to her, so don't get me started on that... ) and when ever I fill her car up, I use premium.

No knocking, noises, smell etc. Everything works fine so far.

until the end

I think the c300 diff. My frand fill the tank with 89 oct. and naver have problem

Carsy

If all else fails read your manual.

You are crazy to use lower octane fuel than recommended.

It will certainly cost you more in maintenance in the long run.

until the end

The problem is we dont have higher octan
Today i used 2 octan boster and the car is 100% normal no knocking and the car is alive

AkaSigFreak

If you use lower octane then recommended- the car is equipped with Knock Sensors. This will retard the ignition temp/timing to accomodate for the crappy gas/lower octane rating. The cars computer will keep a log of this and if you have problems- the dealer will pull the fuel map.
It's a simple mathematical equation:
Mercedes-Benz + Cheap Gas=SCREWED

until the end

I take the car to the delar and i told them my problem and i leave the car for 2 days and when i return to them thay told my that avry think is ok thay didnt see any problem with it (the car have extra 10 km when i take it )and all the cars in jordan have the same problem and the advisor told me dont wast your mony ther is no solution hmmmmm
And he told me buy octan boster ???
Is that your solution MB

AkaSigFreak

Where are you? Tell the "advisor" to put it in writing. Then let me know what he says.

until the end

Im in jordan amman
ill go to the delar nex week

MBRedux

Does anyone here truly understand what Octane Booster really does... how it really works, if it does? (Most tests show it's nothing but Snake-Oil)

All it does is DELAY self ignition flame-out! It makes the gasoline LESS combustable... thus the term that it helps eliminate "pre-detonation".

It does NOT give you MORE power... it is NOT a magic potion that increases your HP... that's all hyperbole !

The ONLY reason you achieve the rated HP of your high compression engine, and not below it with high Octane fuels is because the fuel "waits" longer to ignite, thus allowing the piston (of a high compression or turbocharged engine only) to reach the effective stroke point to achieve maximum compression and efficiency before the gasoline/air mixture ignites via the a spark ignition rather than all by itself.

American fuels are NOT a single octane rating but an Average Reading between two separate rating systems... RON + MON/2... So have your fuel tested... it means NOTHING because fuels are blended, then the ratings are averaged.

Here maybe this will help explain things.

Research Octane Number (RON)
The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.

Motor Octane Number (MON)
There is another type of octane rating, called Motor Octane Number (MON), or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load, as it is determined at 900 rpm engine speed, instead of the 600 rpm for RON. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON, however there is no direct link between RON and MON. Normally, fuel specifications require both a minimum RON and a minimum MON.

Anti-Knock Index (AKI)
In most countries, including Australia and all of those in Europe, the "headline" octane rating shown on the pump is the RON, but in Canada, the United States and some other countries, like Brazil, the headline number is the average of the RON and the MON, called the Anti-Knock Index (AKI, and often written on pumps as (R+M)/2). It may also sometimes be called the Pump Octane Number (PON).

Difference between RON and AKI
Because of the 8 to 10 point difference noted above, the octane rating shown in Canada and the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel. (So a 93 Octane R+M/2 rating here in the USA will be a 97-98 RON elsewhere in the world, like in Europe... two different numbers but the fuel has the same properties.)

Observed Road Octane Number (RdON)
The final type of octane rating, called Observed Road Octane Number (RdON), is derived from testing gasolines in real world multi-cylinder engines, normally at wide open throttle. It was developed in the 1920s and is still reliable today. The original testing was done in cars on the road but as technology developed the testing was moved to chassis dynamometers with environmental controls to improve consistency.

2012c350

I'll be using Sunoco Premium/Ultra (or whatever their high octane is called.) Same stuff I've been running in my Cobra. I believe the Mustang "recommends" premium but the C350 claims it's required. If it's required by the manufacturer I'll be more certain to use it and not rely on anti-knock sensors (which I wouldn't in either case, but certainly not if it's required.)

Glyn M Ruck

Please run the highest octane fuel you can find (at the pump - not AVGAS) or your vehicle will run permanently retarded as the ECU pulls back the timing at the onset of knock with resultant loss of efficiency. These cars run a very conservative engine map however. If your car is actually knocking & it's bad if you can actually hear it get your dealer to set the car to a lower octane map with a Star. It is selectable.

Smell has nothing to do with gasoline performance. Some gasoline fractions react with the catalyst & produce some nasty smells. More noticeable with new Cats than old well used ones.

As Redux says forget the Octane boosters. The kind of crap you can buy at a spares shop almost universally retards flame front propogation.

Decent octane boosters are terrible components that you can't possibly sell in concentrated form to the public. They are handled in refineries by staff in full Haz suits.

As engines age & foul themselves so their octane requirement increases.

EDIT - BTW if you can hear more than the slightest trace knock at low speed have your knock sensor checked. You should hear a trace rattle & then it should shut up. You won't ever hear high speed knock.

The greatest benefit to be enjoyed from higher octane fuels is they allow higher compression ratios & more advanced timing to be employed IF THE ENGINE IS DESIGNED TO HANDLE THIS.

Otherwise an engine has a rising maximum octane requirement. Anything over that is octane giveaway for no benefit.

Frequently higher octane fuels are more dense fuels. More dense fuels contain more potential energy if they can be combusted completely.

The Octane rating of a fuel in isolation is purely it's resistance to preignition or knock, detonation, pinging etc by whatever name you know it.

Some of the Google comments above are slightly shaky but in layman's terms achieve to illustrate the picture.

until the end

I will remap the car this week i called the delar today and ill post any new info