Branded v Supermarket fuel

Meaker said:
The big issue as exactly the octane rating pertains to is knock, if you put 95 in a car designed for higher it could have uncontrollable knock and the engine could be seriously damaged.

If its preferred rather than required then it will have the capability to regulate itself properly with the lower standard.

My car is tuned for higher octane and while it could just be my engine my valves and pistons were noted to be very clean, I've only run it on 99.
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Not strictly true. While an engine will knock when run on a fuel with insufficient knock resistance (Octane) ECUs for at least 20 years have utilised closed loop ignition sensors and will retard the ignition when knock is detected and in some cases introduce more fuel.

We are now at a stage where they also model ignition efficiency and can target increased cylinder fill (Boost) to deliver the target torque in a knock limited situation where possible
 
Most modern cars will go down to something like 90ron before they start to knock, even ones which come tuned for premium fuel. I don't think you can even buy it that low anywhere in Europe.
 
MagicBoy said:
LOL, yet another pithy one liner ninja edited to make it look less Nasher-ish.

"Hi Mr Local Librarian. Do you have the manual for a 'most modern cars'? Thanks."
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Have you heard of this thing called google?

Doesn't your car have a manual?

Do I just attract idiots or something?
 
Nasher said:
Have you heard of this thing called google?

Doesn't your car have a manual?

Do I just attract idiots or something?
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No, but to say most modern cars will run on 90 is unbelievable. You cant even buy such fuel as EN228 has a 95 RON mibnum and there is no way an engine is going to be developed for 90RONn rather than minimum 95 RON, the compromises made would be massive in terms of CO2 and emissions penalty. Especially when EU OEMs have fleet targets for CO2 emissions so every gram counts. All engines will be setup for 95 RON min and some can benefit from higher with either passive or active ignition management

Why have you invented such a claim?
 
Here's the one specifically from my Auris :
Screenshot%202020-04-29%20at%2012.26.38.png
 
Simon said:
No, but to say most modern cars will run on 90 is unbelievable. You cant even buy such fuel as EN228 has a 95 RON mibnum and there is no way an engine is going to be developed for 90RONn rather than minimum 95 RON, the compromises made would be massive in terms of CO2 and emissions penalty. Especially when EU OEMs have fleet targets for CO2 emissions so every gram counts. All engines will be setup for 95 RON min and some can benefit from higher with either passive or active ignition management

Why have you invented such a claim?
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Yes but the knock sensor will handle fuel lower than 95. Just as cars which like 98 are fine on 95..
 
Nasher said:
90 or 93 I can't remember, probably varies.

The car's manual lol. Read it.
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So i've tried 3 out of interest very quickly;

Skoda Octavia 2017 - helpfully says 'see the sticker on the filler cap' - pretty sure from memory this says 98 preferred, 95 minimum

Toyota GT86 2017
Unleaded gasoline (octane rating of 93 [98 RON] or higher) If unleaded gasoline with an octane rating of 93 (98 RON) is not available, unleaded gasoline with an octane rating of 91 (95 RON) may be used with no detriment to engine durability or driveability.
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Ford Focus 2018
Use minimum 95 octane unleaded gasoline that meets the specification defined by EN 228 or the equivalent national specification.

Your vehicle is suitable for use with ethanol blends up to 10% (E5 and E10).
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So far, seems 95RON minimum is common, not 90 or 93, perhaps it would be quicker if you gave us some examples of most modern cars that state 90 or 93 in their manual?
 
Nasher said:
Yes but the knock sensor will handle fuel lower than 95. Just as cars which like 98 are fine on 95..
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That does not mean it will perform the same

Nasher said:
90 or 93 I can't remember, probably varies.

The car's manual lol. Read it.
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Absolutely not. I have first hand back to back tested 95RON and 99RON on a stock M4 on the dyno and seen a 60bhp difference in peak power output.

I'm can't post dyno graphs because I'm not involving the names of the company I was working with
 
Frozennova said:
Absolutely not. I have first hand back to back tested 95RON and 99RON on a stock M4 on the dyno and seen a 60bhp difference in peak power output.

I'm can't post dyno graphs because I'm not involving the names of the company I was working with
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Yea it will be down on power and mpg, but it won't destroy itself if it has a knock sensor.
 
Yeah there’s a few, Pump Octane, Motor Octane and of course our UK Research Octane Number.

Of course let’s not get the units of measure get in the way of fact though. ;)
 
theone8181 said:
I'm assuming he's thinking of the USA measure of Ron, I can't remember what it's called but I think 90 over there is the same as our 95.
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Until very recently China were selling petrol with as low as 89 RON (I think India still do). They are mostly the same cars we buy elsewhere with the same engines...
 
Nasher said:
Until very recently China were selling petrol with as low as 89 RON (I think India still do). They are mostly the same cars we buy elsewhere with the same engines...
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Yeah and in those regions OEMs have started putting magnets in the fuel tanks to try managing the metal particle debris in the fuel.

I think China V is 89-95 RON as part of their de-sulphur of fuel regulations in 2013
 
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