More MPG when using super unleaded

Sylar

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C180k appears to be doing more miles per gallon on super over the cheap stuff.

Anyone else finding this?
 

Sasha94

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More often than not it's a placebo effect but I don't really care, I still use only the more expensive of the unleaded fuel on offer wherever I'm filing up. Usually quite often in my land of 21 MPG being actually quite agreeable :)
 

Uncle Benz

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I've extensively tested the range of higher octane fuels available. My m3 will only run on 98, and I've always fed my c32 on premium gas too, as 400bhp from 3.2 litres is probably a bit much for 95. My c55 and SLK55 were fine on either, as at 367bhp from 5.4 litres, it's hardly what you would call a high output engine. It always felt slightly peppier on the higher octane stuff, but I'm pretty sure it was mostly placebo. One thing I'm certain of, economy appeared no different. If there was an improvement in mpg, the higher initial cost of the fuel certainly outweighed any saving on consumption. My advice, unless you have an engine producing more than 100bhp per litre of displacement save your dosh and just buy regular 95 octane. If over 100bhp per litre you will probably find the manufacturer recommends 98 octane, and you'd be well advised to heed their advice.
 
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Sylar

Sylar

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Im getting 27mpg around town on normal and 32 on super..... according to the computer anyway. Ill start monitoring the old way and see if the computers a liar
 

Craiglxviii

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I've mentioned this before. Ordinary non-tuned MB cars will not see any benefit from a 5 or 3 octane increase. Some cars (AMG tuned) are set up for it, the rest are not. Everything else is down to the pure placebo effect. Also subconscious and selection bias accounts for far more than the difference in raw fuel performance.
 

daveenty

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Most cars will adapt to whatever fuel they sense and adjust various parameters accordingly.

Mine was mapped specifically for 99RON though, as Craig states, unless you're running a sensitively tuned ECU, you won't really notice much difference. I had to put a lower rated fuel in it once and it was very noticeable but wouldn't have been on a standard map.
 

LostKiwi

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Look in the owners manual and see what the recommended fuel is. If it's higher than 95 you may see an improvement by using 98. If it's not you won't.
 

Uncle Benz

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Most cars will adapt to whatever fuel they sense and adjust various parameters accordingly.

Mine was mapped specifically for 99RON though, as Craig states, unless you're running a sensitively tuned ECU, you won't really notice much difference. I had to put a lower rated fuel in it once and it was very noticeable but wouldn't have been on a standard map.

Correct. The ignition timing is essentially controlled from a look-up table, sometimes referred to as a map. Knock sensors are used to detect pinking and if they report any, the ignition timing is retarded to eliminate it. If the map has values of ignition timing which run to a 95 octane requirement, nothing will be gained from using higher octane fuel. It simply can't advance the timing any further.
 

Headhurts

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I have since new used premium diesel in my E350, I'm not sure what if any difference in mpg but use it more for the cleanses added to the fuel.

Surely the petroleum companies would not lie to us?




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dreadlockdw

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I have since new used premium diesel in my E350, I'm not sure what if any difference in mpg but use it more for the cleanses added to the fuel.

Surely the petroleum companies would not lie to us?

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It ought to be relatively easy to check for any discernable difference in mpg between fuels over a few tankfuls ie say 1000 miles on each fuel

Honest John claims the extra power enables a driver to change up quicker and thus save fuel

Personally I use it in the belief, as above, that the cleaners/additives will extend the life of the engine, although this is next to impossible to measure at a personal level...
 
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Craiglxviii

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It ought to be relatively easy to check for any discernable difference in mpg between fuels over a few tankfuls ie say 1000 miles on each fuel

Honest John claims the extra power enables a driver to change up quicker and thus save fuel

Personally I use it in the belief, as above, that the cleaners/additives will extend the life of the engine, although this is next to impossible to measure at a personal level...

There are no extra cleansers. It's just a higher anti-knock rating.
 

C350Carl

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With regards to fuel and this is for both petrol and diseasel and I have this from a very good friend who works for Lubmarine (subsidiary of Total).

All fuel has to conform to a set standard in the UK so for Petrol it is BS EN228 and Diseasel it is BS EN590.

The only differences in any of the manufacturers products is the additive package. This includes detergents (for example Shell call them efficiency improver chemicals under the name of Dynaflex) but essentially they are detergents/cleansers to prevent corrosion and build of deposits or gunk.

So the price differences you see are mainly for the additive package that is specified by the supplier.

If you think I'm wrong have a google of how many fuel refineries there are. Then have a think at how many different types of petrol and diesel you think there are eg:

Asda
Morrisons
Tesco
Sainsburys
Shell
BP
Total

And a whole host of others you will see around. There are more suppliers who market their own 'Snake Oil' fuel. But the base fuel is always the same. It is the additives that make the difference and what the big oil companies pump (no pun intended) £bn's into R&D for.

To save you googling the refineries there are 6 - http://www.ukpia.com/industry_information/refining-and-uk-refineries/refineries.aspx

To go back to the OP. Yes you may get more MPG from S/UL however you have to work out if the cost difference is worth it.

EG the cost difference is around 10ppl for the super fuel. So if you have a 60ltr tank that's an extra £6. if you are only gaining say an extra 20miles of range you could probably do that distance on £6 worth of 95Ron.
 

Craiglxviii

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Oi, don't let fact and data get in the way of hyperbole and personal anecdotes of uncontrolled driving tests!
 

Steve@Avantgarde

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As someone has stated, the fuel additives in the 99RON will make the fuel burn a lot more efficient, so yes you should see an increase. Whether that justifies the price of paying the extra for the fuel though.

I have found the cheapest way is to get my fuel from Costco at around 5p under the normal pump price from a supermarket. Filled up with diesel yesterday at £1.10PL rather than £1.15 from the local tesco. The local BP is at £1.17PL
 

daibevan

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I always buy the cheapest petrol I can. Our local BP often has low price fuel days when they match the supermarkets. I also buy redex when its on offer, usually half price in Tesco. If I have used several fills of supermarket petrol I'll give it a squirt of redex, partly for my peace of mind , but mostly to please my wife " you're not putting that Morrison's /Tesco Sh1t into our lovely Merc are you.
 

MalcQV

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My daily drive and one of my weekend cars get bogo from the supermarket.
My 360 always gets super unleaded and mostly from Shell because they're recommended by Ferrari and I'm very gullible.
I have never put any normal premium fuel in the 360 but I did in my F355 when I could not get super. I never noted a difference with that. However it was designed to run on 95 Octane I believe.
I guess on the track there might have been a noticeable difference but not on the road.I think quite often the placebo effect kicks in but if the OP says the MPG is better then that's easily proved. I did try them many years ago in daily drives and nothing improved but then they were older cars still.
 

Simon Barry

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My bog standard (Non supercharged & no turbo) 500 engine gets spoilt regularly with
some of Tesco`s finest. It gulps it greedily, returns good mpg & sails happily into the sunset.
 


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