Which fuel do you use in your merc?

[beege]

Hi all,

I’ve got a C200 with the 1.5EQ boost petrol engine. For the last few months I’ve been using Asda Petrol which seems okay, put a tank of Costco super unleaded in the other day but not convinced it’s gives as many MPG as Asda.

Just wondering what fuel everybody else uses? What do you find best in terms of MPG/performance. I’m not exactly a racing driver (hence the 1.5 petrol), but occasionally floor it at a roundabout or a junction.

I don’t mind paying a bit more for fuel if the economy and performance is better.

Thanks in advance
Beege

 

[DSM10000]

This topic has been covered ad infinitum on here
If you use the search function you will find many posts ....

Short answer : All fuel is made to the same UK standards Some contain additives that may help.

 

[Gazwould]

Engine has turbine ?

 

[beege]

Engine has turbine ?

Yes it does

 

[beege]

This topic has been covered ad infinitum on here
If you use the search function you will find many posts ....

Short answer : All fuel is made to the same UK standards Some contain additives that may help.

Thanks DSM, I’ll have a look back through previous posts

 

[GeeJayW]

Best fuel economy OR performance, you choose. Can't have both at the same time from any fuel.

If the handbook says use super unleaded, then use super unleaded.

Even if the handbook for the car says use regular 95 RON fuel, then using super-unleaded 97+ RON may give a small performance benefit which if not utilised may (depending on how the increase in octane is achieved) result in some minor fuel economy improvement. There are also some differences between brands at the same grade, but in the UK there's not a huge amount in it.

As mentioned already there a number of threads that discuss all of this.

 

[DSM10000]

Thanks DSM, I’ll have a look back through previous posts

Try different search criteria etc. The search function can be quite specific.

 

[AltonAnt]

I definitely notice a big difference using vpower. I have no idea about MPG but I notice an increase in power but more importantly smoothness.

 

[markjay]

Personally I have never noticed any difference in performance between fuels. I don't measure mpg.

In my own cars I use premium fuels because of the long-term effect of the additives.

But I wouldn't expect to notice any difference otherwise i.e. in day-to-day driving.

 

[clk320x]

I definitely notice a big difference using vpower. I have no idea about MPG but I notice an increase in power but more importantly smoothness.

This is most likely due to the placebo effect.

 

[snipez999]

I have used Tesco ultimate 99 or whatever they call it on many of my cars such as the DB9, Bentley V8S, S63 and E63S. Occasionally I will tank up on shell v power or BP ultimate - but don’t go out of my way to - and honestly see nor feel not an iota of difference.

 

[ash59fifty-uk]

I use what is recommended on my fuel filler cap... 99RON

V power

Edit: I think it might say 98RON on there, can’t remember. Either way super unleaded only. Costco super unleaded is the cheapest high octane but I have about 100 shells between me and the nearest Costco outlet. Also too far from a Tesco for their equal offering

 

[AltonAnt]

This is most likely due to the placebo effect.

 

[AltonAnt]

I should add my only local source of fuel is Sainsbury's and I have been visiting a relative in hospital for the past month which takes me past a Shell garage. The difference is noticeable for me.

 

[190]

I have never noticed a difference in the way a modern car performed between super market fuel and branded fuel. Even if there was a difference in the fuels, the engine management systems would just adapt to suit. I can accept that there are additive differences but performance in normal part throttle driving, no. You need a relatively big change in HP to be able to notice it.

If you take a very old engine with no sensors or computers and therefore no means of adaption then I have noticed a difference For example Shell fuel pinging more readily than supermarket and on a different ocassion the other way around. That's probably just how long the respective fuels have been in storage.

 

[a111r]

Bio-diesel or occasionally, diesel.
Not Petrol.

 

[markjay]

I have never noticed a difference in the way a modern car performed between super market fuel and branded fuel. Even if there was a difference in the fuels, the engine management systems would just adapt to suit. I can accept that there are additive differences but performance in normal part throttle driving, no. You need a relatively big change in HP to be able to notice it...

This is my experience as well.

I am not saying there isn't a difference that can be measured on a dyno, or felt on a track day. But there's definitely no difference that I can feel during normal day-to-day driving.

 

[GeeJayW]

Some drivers need a very big difference in performance before they notice it. I've done work where we modified a normal road car so that we could switch fuel just by pushing a button on the dashboard. It responded very well to changes in octane. We made no changes to the engine control system at all. Even when we were running fuels that offered quite substantial differences in performance, many drivers could not tell.

We also modified a very high performance modern car to allow us to switch fuels. We then let a professional driver take the car on a track and see if he could tell the difference between a matrix of fuels (we also had a data logger and GPS on the car to cross correlate his comments with hard data). The only person that knew which fuels were which was me. The technicians knew only the fuel codes. The driver was not told whether the fuel had changed or not and had no timing data. The driver picked it right every time.

My advice to anyone is that if you can't tell the difference and the manual says use regular, then apart from improved (or extra) additives in (some) super unleaded fuels there is no strong argument for spending the extra cash. This is also true for diesel.

As for the differences between brands of fuel.
Regular:
In the UK all fuel suppliers include additives that have similar functionality, but vary in chemistry, dose rate and effectiveness. Typically in my experience, fuels from the major oil companies tend to have more effective additives than those from supermarkets. However supermarket fuels are typically fit for purpose.

Super unleaded:
Some fuels achieve the increased octane rating by the inclusion of ethanol. This can be supermarket or Major Oil Co. fuels, but not necessarily all of them. Ethanol is cheap and has good octane quality, but it contains oxygen. It can also be produced using nominally sustainable methods, so is seen as having some level of environmental benefit.

However Oxygen is not a fuel so the energy content per kilogram for ethanol containing fuels is lower compared to fuels that achieve higher octane by including high octane hydrocarbon components. So some super unleaded fuels will give less fuel economy than others. This is a bit of a crap shoot because without analysing it, nobody knows how fuel at the forecourt was formulated.

It's perhaps worth noting that octane (RON) is just an inspection property of the fuel. It's a headline number and not a definition of how well a fuel performs in an engine and there are numerous ways of formulating fuels that meet a certain octane, but then offer different performance levels in the engine.

 

[snipez999]

Well if I can’t feel it in a 612bhp car that gets a good dual carriageway run twice a day, then the margins must be insignificant. Just saying [emoji3][emoji106]

 

[gramey]

I never use supermarket fuel but nor do I use Premium unleaded in my car or motorcycle , I use BP in the hope that the additives keep the engine clean internally but ml SL350 isn't a performance car and my Yamaha 1000 has enough power without worrying about 1 or 2 bhp from petrol that's 10p a litres dearer.