Standard or Super Unleaded?

[Bumblebee16]

Hi,

I pick up my Yaris Hybrid tomorrow.  

 

Should I use standard unleaded, or Super unleaded petrol?

Has anyone here done comparisons on the differences between the two grades?

Is it cost effective to use the higher octane fuel all the time?

 

I look forward to hearing your views.

[Anthony Poli]

Regular unleaded, the only fuel to avoid is higher ethanol content.


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[Justhandguns]

2 hours ago, Bumblebee16 said:

Hi,

I pick up my Yaris Hybrid tomorrow.  

 

Should I use standard unleaded, or Super unleaded petrol?

Has anyone here done comparisons on the differences between the two grades?

Is it cost effective to use the higher octane fuel all the time?

 

I look forward to hearing your views.

 

Lots of threads (and evidences) suggested that all fuels are essentially the same, just that different addictives are added to manipulate the properties such as detergents and lubricants etc. I do not think you can notice any difference with our engines in terms of power, hybrid or non-hybrid. 

 

1 hour ago, Anthony Poli said:

Regular unleaded, the only fuel to avoid is higher ethanol content.


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Just curious, how much ethanol content do we current have in regular unleaded? 5%?

[FROSTYBALLS]

The level of ethanol was revised in 2013 - now up to 10% in petrol. Petrol containing 10% ethanol must be labelled as such (E10) at the pump as not all vehicles are compatible with this level.

[Bumblebee16]

2 hours ago, Anthony Poli said:

Regular unleaded, the only fuel to avoid is higher ethanol content.


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36 minutes ago, FROSTYBALLS said:

The level of ethanol was revised in 2013 - now up to 10% in petrol. Petrol containing 10% ethanol must be labelled as such (E10) at the pump as not all vehicles are compatible with this level.

Thank you.  I had no idea about ethanol content in fuel.  

[njbrice]

Super unleaded burns more efficiently so less carbon build up in the medium to long term and marginally better mpg.

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[bathtub tom]

2 hours ago, njbrice said:

Super unleaded burns more efficiently so less carbon build up in the medium to long term and marginally better mpg.

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On what do you base that assumption?

I understand the only difference between higher and lower octane fuels is the ability to prevent pre-ignition. Previously by lead based chemicals.  I believed there was no difference in the calorific value of different petrols.

As  A7s were pre-war, they weren't subject to higher octane fuels and as such had to tolerate lower octanes with the subsequent valve seat regression.

The engine I recently re-built rattles like billy-ho, because I set the valve tolerances on the 'loose' side, on the assumption they ain't going to get any looser and I may have to tighten the head studs.

[mickandjanet]

If as many of you say there is no difference between the grades of fuel why is the higher grade of fuel dearer, or do you just throw money away to fill up with super unleaded.

[Mike J.]

21 minutes ago, mickandjanet said:

If as many of you say there is no difference between the grades of fuel why is the higher grade of fuel dearer, or do you just throw money away to fill up with super unleaded.

Check out: Wikipedia entry on Octane

It mentions this: "Octane ratings are not indicators of the energy content of fuels. They are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where the octane number is raised by blending in ethanol, energy content per volume is reduced."

Basically, unless you have a turbo charged or high compression engine, use normal unleaded. The Yaris Hybrid has a high compression (13.4:1) which would point to using super unleaded, but this is not straightforward. As the engine uses a version of the Atkinson cycle the actual compression ratio is low (the the inlet valve is open during the start of this cycle) and the expansion is high (13.4:1) so normal unleaded is the correct fuel.

[Justhandguns]

On 07/10/2017 at 1:04 PM, mickandjanet said:

If as many of you say there is no difference between the grades of fuel why is the higher grade of fuel dearer, or do you just throw money away to fill up with super unleaded.

The 'super' or premium fuels are not just about higher octane numbers. They contain more additives such as detergents and lubricants as I mentioned before to help cleaning up and lubricating your engine, although for most of our cars, the difference they make are minimal. 

[FROSTYBALLS]

The Toyota specification as regards octane states a minimum requirement - and in my current manual (Aygo) the minimum requirement is "Research Octane Number - 95 or higher. The same applied to my previous Auris, and presumably to the majority of Toyota's petrol and hybrid models.

The use of super unleaded in place of standard unleaded, whether that is all the time or occasionally, would still meet Toyota's minimum requirements. 

Incorrect fuel would be below 95 RON, fuel that doesn't meet EN228 (if within the EU), or fuel that contains more than 10% ethanol.

If one chooses to use super unleaded, it meets Toyota's requirements, carry on - it is your personal choice.

[Ant182]

On 03/10/2017 at 10:02 AM, Bumblebee16 said:

Hi,

I pick up my Yaris Hybrid tomorrow.  

 

Should I use standard unleaded, or Super unleaded petrol?

Has anyone here done comparisons on the differences between the two grades?

Is it cost effective to use the higher octane fuel all the time?

 

I look forward to hearing your views.

(These are just my thoughts) Over the years I've had many performances cars used rolling roads and had cars mapped on 99octane and 95octane and I've come to conclude that it all comes down to how the cars are mapped and on what fuel.  So Id say stay away from Morrisons and Asda petrol and there not as refined and leave more deposits in your engine than the normal petrol companies Esso/Shell/Jet etc, I carried out my own tests back to back and found that my engine would run rough and use the fuel faster if it was Asda/Morrisons so I never use them now. I only use 99 in my sprint car as it also protects the engine a little bit more when the car is using high revs, this was advised my a Toyota performance tuner.   I hope this helps, again these are just my own thoughts and info I've gathered myself. 

[martswain]

Have tried Super in 2 Prius (1.5 and 1.8), Lexus CT200H and my current 2014 Yaris Hybrid.

Conclusion = Waste of Money

No difference in performance or economy, no issues with any engine or fuel system..

Tesco Unleaded has been fine in all of my vehicles, including a Porsche 911 which only needed 95 RON.

The only vehicle that specified Super was a Jeep Grand Cherokee SRT8, so that was what it got fed, average consumption was 15.7 MPG, so it had a lot of it !