That age old question - Super or Regular Unleaded

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sgregory124

MB Enthusiast
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Location
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E63S
All,

I imagine this question has been done to death on every forum on the planet and I think I know the answer, but wanted to double check prior to picking up my 2017 C63S on Friday, so.....

I am aware that the manual for this car states I need to use 98 RON or above petrol, I have no issue with this and it makes complete sense to me, if I can fill with Super then I will. However, if I need to put boggo 95 RON in at some point (in the event i'm somewhere with no 98/99 availability), can I do it without damaging the engine?

Yes I know I will lose some power because of that (or at least I think I will) but, i'm concerned from stuff i've read that 95 will permanently damage the internals. One of my previous performance cars (an E46 M3) that stated 'Super' only, never had any issue running on straight 95, so i'm pretty sure i'm being paranoid. That being said I would appreciate someone with more knowledge than me putting my mind at rest!

Thanks in advance and sorry for dredging up the old chestnut.....:)

Simon
 
Absolutely under no circumstances put cheap fuel in your AMG!! But if you have to then do so but it is highly recommended not to unless you have no choice. But don’t put cheap fuel in, but you can if you need to.

Thats what my mate Boris says.

Me personally I wont put cheap stuff in.
 
Absolutely under no circumstances put cheap fuel in your AMG!! But if you have to then do so but it is highly recommended not to unless you have no choice. But don’t put cheap fuel in, but you can if you need to.

Thats what my mate Boris says.

Me personally I wont put cheap stuff in.

Are you confusing cheap with poor quality?

Fuel in the UK is all produced to a regulated minimum standard.

To answer the OP's question, if you can only get 95 RON fuel then the engine will adapt via the engine sensors and will probably retard ignition slightly.

The higher octane fuels often but not always also have cleaning additives but for one tank or part tank there will be no damage
 
Some filling stations super unleaded only has a rating of 97 Ron.
 
If i can't get Shell V Power / Tesco Momentum.

I put in a small amount of 95 just to get me going again.
 
So the general consensus then (as I see it) is that a tank of 95 here and there isn't going to detonate the engine. As I said, the only reason I won't buy Super is availability, cost isn't an issue - i'm more concerned about being in an area that doesn't have it (some areas of the Highlands i've been to for example don't have many filling stations let alone Super Unleaded!).

Shouldn't be a problem on Friday as I have a 131 mile drive from Bristol to just outside Nottingham on the M4/M5/M42 - planning on filling up with Super beforehand in the local area and from what I can see, there are a few places I can do that (off J19 of the M4).
 
So the general consensus then (as I see it) is that a tank of 95 here and there isn't going to detonate the engine. As I said, the only reason I won't buy Super is availability, cost isn't an issue - i'm more concerned about being in an area that doesn't have it (some areas of the Highlands i've been to for example don't have many filling stations let alone Super Unleaded!).

Shouldn't be a problem on Friday as I have a 131 mile drive from Bristol to just outside Nottingham on the M4/M5/M42 - planning on filling up with Super beforehand in the local area and from what I can see, there are a few places I can do that (off J19 of the M4).

Like others have said the fuel regardless of where it is from has to meet certain UK regulations. I’m going to assume most fuels if not all fuels come from the same refineries??

Would an octane booster help in situations where you are using 95RON more often??
 
Like others have said the fuel regardless of where it is from has to meet certain UK regulations. I’m going to assume most fuels if not all fuels come from the same refineries??

Would an octane booster help in situations where you are using 95RON more often??

That was my feeling, never had an issue with the M3 on regular unleaded and that had a pretty highly strung engine too. I have filling stations local to my house I can get Super so i'm not concerned, it's only really for long trips away.
 
I did a trip round Scotland and got caught short of super in my 2013 C63. It's not turbo but it was fine. If I go again I would take a few bottles of octane booster.
 
If y
That was my feeling, never had an issue with the M3 on regular unleaded and that had a pretty highly strung engine too. I have filling stations local to my house I can get Super so i'm not concerned, it's only really for long trips away.
If you are running low and the only station nearby doesn't sell 98+ rated, don't fill up. Just put half a tank of 95 in and then top up with 98+ when you are able.
 
Years ago I called at Asda forecourt (not for fuel) in a Mitsubishi Evo X and the tanker driver delivering fuel at the time said out of the blue, “ I hope you’re not putting this shit in that “.
Enough said I thought. :)
 
Years ago I called at Asda forecourt (not for fuel) in a Mitsubishi Evo X and the tanker driver delivering fuel at the time said out of the blue, “ I hope you’re not putting this shit in that “.
Enough said I thought. :)
I am sure he was an expert in Petrochemical formulations.;)
 
Appart from octane rating the 95RON is more likely to contain 5-10% BIOFUEL depending on which refinery/depot supplies you locally. Discussions about this already on the forum if you do a search
 
If your at all worried about detonation, why don’t you keep a couple of bottles of Octane booster(Millers was always a good one) in the boot for the times 98/99 is not available. I used this in an imported Impreza and it put the rating up to 101
 
I have lost count of the number of journeys that have been made to magically include a fuel stop at a Shell garage for their V-Power go go juice 😊
 
Enough to fill a jerry can is alright, full tank? I wouldn’t personally, I keep one in the boot for those squeaky bum moments when I can’t get to a shell before I run out... which I did a few months back and got stranded at the end of a slip road on a very busy A14!
 
At the beginning of my ownership with my W202 C43, I would fill up exclusively with 98RON or V-Power. Switched to 95RON and have been using it for over 10 years with absolutely no side effects apart from having a softer wack on my wallet.

For the W204 C63 however I'll stick to the good stuff, with priority to V-Power or 98RON if V-Power is not available when I need to fill up.
 
Shell have an app for Android & Apple allowing you to locate their filling stations, and also have a web page where you can plan your route & refuelling:-
here.

NJSS
 

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