Fuel Quality

[Kenny]

We have had a few messages wondering about the quality of fuel required to run a Focus RS to its optimum. Obviously being a performance car you want to use the best available fuel as it is just like ourselves if you eat junk food you will run operate to your maximum so always be advised to run on 98 RON or higher. If using 95 RON in an emergency then you would be best to keep the car below 4000rpm (no WOT driving) until you can use an octane booster or source better quality fuel.

 

What the 2016 Focus RS owners manual states:

We recommend regular unleaded gasoline with a minimum octane rating of 95 RON. Use premium unleaded gasoline with an octane rating of 98 RON or higher for optimal performance of your vehicle. Recommended fuels are an important part of the correct maintenance and optimal performance of your vehicle. Fuels with octane ratings below 95 RON are not recommended. The use of gasoline with an octane rating lower than 95 RON can lead to severe mechanical damage. This may also degrade vehicle performance and could lead to engine damage that may not be covered by the vehicle

Warranty:
Note: We recommend you use only high quality fuel without additives or other engine treatments.
Your vehicle is suitable for use with ethanol blends up to 10% (E5 and E10).

Long-Term Storage:
Most gasoline contains ethanol. We recommend that you fill the fuel tank with fuel that does not contain ethanol if you intend to store your vehicle for more than two months.
Alternatively, we recommend that you seek advice from an authorized dealer.

[ianc]

What about the American cars? Do they have to run on 95ron and below ?

[howsey]

Exxon Supreme and Mobil Super+ Unleaded Octane 91-93. Their best is worse than our average, that’s why it’s cheap/cheaper. I’ll be happy using 95 for three years.

[cs400]

I think you’ll find it is calculated a different way in America, which means their 95 is equivalent to our 99!

I just can’t find the link at the moment.

Also you won’t get full performance from the car unless you use 98 or above. You also get better MPG with better fuel, so the price difference doesn’t come to much.

I would prefer better performance personally 🙂

[howsey]

I’ll just put 95 in. I’ll be fine.

[Turbo]

CostCo have a new fuel station at their depot in Lakeside Essex and the 99 octane is cheaper there than supermarket 95 octane locally.

You do need a CostCo membership card and can only pay with a debit card or American Express.

[71-bda]

Howsey, with 95 octane instead of 98 or 99 etc you will be down on power and closer to pinking in certain situations. Im definitely going for high test !

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No nothing.

No Mods. No rockers. Just a chunky knob, thats now been replaced by an RS knob innit.

No tackiness.

Std as Ford intended, but with a space saver wheel and jack and nuts and wheel brace. oh.. and flaps, a man has got to have flaps.

Innit?

 

[howsey]

I’ll take your word for it, Mike. I’ll go with 99………five months later.

[chris250]

There are 2 tests for the AKI (anti-knock index) of fuel, RON and MON.

 

Here in the UK we use the RON rating but in america they add the results of the RON and MON tests then divide it by 2.

 

I’m in the middle of testing the effect of the different super unleaded fuels on a tuned MK3 and I can safely say already it makes a massive difference which fuel you choose to run on the power these cars develop.

[18stealth]

It’s all well and good looking at the performance, but the critical thing here is damage, cracks between valves, etc.  Only time will tell with this, and most of the vehicles in “this class” attract those who always look for more, and perhaps it is those that should look into the better quality fuels.

The Ethanol reduces the pre-ignition point, but produces less energy.  I have read that Tesco 99 momentum produces more power than V-power due to the Ethanol content.

It really needs to be looked into more.  I would say that you should be able to achieve the 347Hp / 350 Ps on a well maintained (or even correctly maintained) stock setup.

Does anybody know if / how the RS detects pre-ignition?

[71-bda]

stealth, it has a knock sensor, only one I believe, not one for each cyl.

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No nothing.

No Mods. No rockers. Just a chunky knob, thats now been replaced by an RS knob innit.

No tackiness.

Std as Ford intended, but with a space saver wheel and jack and nuts and wheel brace. oh.. and flaps, a man has got to have flaps.

Innit?

 

[18stealth]

Thanks for the update, bear that in mind.  I’d love to see rolling road comparisons.

[coastliner]

I have seen some rolling road comparisons not on a high performance car so I am unsure what help the results would be with an RS. The car was I believe a Renault Clio and done on from memory The Tonight programme. So the car developed somewhere in the region of 80bhp and the figures were similar on both super unleaded and normal fuel. Like I have said what that means on our cars may not be relevant, but interesting never the less.

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Coastliner

[coastliner]

Found this 5th gear with Vicky Butler Henderson.

 

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Coastliner

[coastliner]

Found the first comparison, I will let you all draw your own conclusions.

 

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Coastliner

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