Black5

My local petrol station has introduced this.
It apparently has a 10% Ethanol content.
Has anyone tried this with their C55?
Does the higher octane rating make any performance difference?
Is it safe?

According to their listing all Mercedes are compatible, and manufacturer approved, whatever that means, but I'm concerned about any possible long term effects.

speed7

I messed up my crank sensor with 100 octane fuel.. don't do it. 93 is the highest I would recommend.

And I think most gas has a 10% blend of ethanol or alcohol. I think there is a sticker on the pump saying that it may contain 10% of something here in MA.

aussie e55

i have been using shell 98 octane in my C55 for the last 4 years with no problems. i believe aussie 98 octane is = to US 93 octane.

Black5

93?
Our "standard" unleaded is rated @ 91 RON, but the c55 requires 98.
I've never used less.
Ethanol blend is becoming more common here, but I've never used it in any of my cars.
The X5 runs on 95 RON minimum.
How does fuel damage a crank sensor?

Black5

OK.
Thanks.
Any thoughts on the 100/10% ethanol?

aussie e55

no thoughts will make some enq. when i get back to work

Black5

Thanks.
I'm curious to see if there is any worthwhile benefit.

Lenin

Not sure about the C55, but in a C32 you could change the octain setting through the STAR system from default of 91 US to 93 US. Is it worth it? Not really if you car is not midified. The ECU can only improve performance with higher octane fuel if the engine is knocking when running on the recommended grade. If your car is modified, then it may not be running at the optimal ignition setting and higher grade gas will advance the timing. I run race gas at the track not because I think it's better but because my car is modified and I don't want the ECU to pull the timing. The subject of timing is complex and some details were skipped in the above opinion, but overall that's my $0.02.

91RS

If they have gas without ethanol, I would keep using that. Also, keep in mind the octane ratings are different for different countries.

speed7

And different states within the US. In California the highest you could get was 91. However just moved to Boston, MA and they have 93 here. Car runs better with 93.. just more smooth. I think its because of the added chemicals California puts in the gas that not only dilutes it but makes it not run as well.

91RS

That,too. What I meant though was that 93 octane here isn't the same as 93 octane in other countries.

speed7

Yeah you're 100% correct. My buddy does races in Mexico and has to use their pump gas with a turbo rotary. He tunes it for gas mixture which is a crap shoot when it comes to octane ratings.

Quickvr4

You won't make any extra power unless you tune for it...in fact you will probably lose power and gas mileage if you just pour it in your tank without a tune. Alcohol has less energy by the way.