The great Fuel debate.
The great Fuel debate.
30-08-2018, 12:45 PM
RON, MON or PON?
I have seen many European/US conversations claiming that one petrol/gas is better than another or higher rated. This may not be the case as different rating systems are used in different countries and so not all numbers mean the same thing. You must be careful to also quote the measurement system used
To see why there are different numbers let us take a trip back in time to World War I. Aviators had a problem, many engines would suddenly self destruct through detonation, which is bad news when you're up in the air. An engine might run fine on one batch of fuel but blow holes in the pistons on the next batch. The fuels seemed the same, weighed the same and may have even come from the same factory.
The fuel companies tried to analysis and standardise the petrol, but were unable to weed out the bad batches. Therefore a standard test engine with a variable compression facility was built and the fuel to be tested run through it. This heavy duty, single cylinder engine would be warmed to a standard temperature and at a set rpm the compression increased until engine knock occurred. this would give its Highest Usable Compression Ratio (HUCR).
But with time it was discovered that different labs gave different results. So in an attempt to produce an unvarying standard, two reference fuels were chosen. The high reference was 2-2-4 trimethylpentane (iso-octane), while the low reference was normal heptane (n-heptane). Once the HUCR was determined a mix of these to fuels was made up that exactly produced the same results as the HUCR test. The result is quoted as the percentage of iso-octane. Hence a petrol that detonated the same as a mix of 90% iso-octane and 10% n-heptane is called a 90 octane fuel.
Since that time a number of tests have come into being to simulate a variety of engine conditions. Motor Spirit is usually rated using the Research or Motor test methods. Both use the same old engine but under different conditions
Motor Octane Test (MON) Research Octane Test (RON)
Inlet air temperature 148.9 C 65.6 C
Engine jacket temp 100 C 100 C
Engine RPM 900 600
As you can see the Motor Octane Test employs a higher temperature and RPM and hence is probably a better indicator for today's engines. Of course the Research octane test gives a higher number and that's why the European manufacturers quote it (RON)
The spread between the two numbers is know as the fuels sensitivity, and it is very important. Because of the variety of engines it is possible for a petrol manufacturer to come up with a fuel that has a high RON, but a lower than expected MON. Hence although it looks normal on the pump it may perform badly. However on another day the same company may make its fuel out of a different blend to get the same RON but a different MON. This is done for profit reasons and is why you occasionally get bad fuel even though it is legally rated the same. In the past with high leaded fuels nobody noticed but nowadays high performance cars do notice - as most of us can attest to!!
In America the service stations use the Pump Octane Number or PON rather than RON. this is the average of RON and MON and gives a much better grade, and is also why the American gas always seems not as good as our when in fact it is is the same (and has better quality control). But even this system can be abused by adding octane boosters to poor fuel. The Japanese cars luckily for members of this club use good old RON!!
Below is an approximate comparison chart, these numbers can vary by as much as 2 grades.
RON MON PON
90 83 86.6
92 85 88.5
95 87 91
96 88 92
98 90 94
100 91.5 95.8
105 95 100
110 99 104.5
So whether you use "Super" or "Normal" now you know where these numbers come from. Remember if your car is tuned on "Super" USE IT, if its a normal car chances are using "Super" is a little wasteful of your hard earned $. (Sorry this keyboard doesn't have a pound symbol!!!)
Higher Octain = harder to detonate, ideal for turbo and supercharged applications.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
30-08-2018, 12:45 PM #1RON, MON or PON?
I have seen many European/US conversations claiming that one petrol/gas is better than another or higher rated. This may not be the case as different rating systems are used in different countries and so not all numbers mean the same thing. You must be careful to also quote the measurement system used
To see why there are different numbers let us take a trip back in time to World War I. Aviators had a problem, many engines would suddenly self destruct through detonation, which is bad news when you're up in the air. An engine might run fine on one batch of fuel but blow holes in the pistons on the next batch. The fuels seemed the same, weighed the same and may have even come from the same factory.
The fuel companies tried to analysis and standardise the petrol, but were unable to weed out the bad batches. Therefore a standard test engine with a variable compression facility was built and the fuel to be tested run through it. This heavy duty, single cylinder engine would be warmed to a standard temperature and at a set rpm the compression increased until engine knock occurred. this would give its Highest Usable Compression Ratio (HUCR).
But with time it was discovered that different labs gave different results. So in an attempt to produce an unvarying standard, two reference fuels were chosen. The high reference was 2-2-4 trimethylpentane (iso-octane), while the low reference was normal heptane (n-heptane). Once the HUCR was determined a mix of these to fuels was made up that exactly produced the same results as the HUCR test. The result is quoted as the percentage of iso-octane. Hence a petrol that detonated the same as a mix of 90% iso-octane and 10% n-heptane is called a 90 octane fuel.
Since that time a number of tests have come into being to simulate a variety of engine conditions. Motor Spirit is usually rated using the Research or Motor test methods. Both use the same old engine but under different conditions
Motor Octane Test (MON) Research Octane Test (RON)
Inlet air temperature 148.9 C 65.6 C
Engine jacket temp 100 C 100 C
Engine RPM 900 600
As you can see the Motor Octane Test employs a higher temperature and RPM and hence is probably a better indicator for today's engines. Of course the Research octane test gives a higher number and that's why the European manufacturers quote it (RON)
The spread between the two numbers is know as the fuels sensitivity, and it is very important. Because of the variety of engines it is possible for a petrol manufacturer to come up with a fuel that has a high RON, but a lower than expected MON. Hence although it looks normal on the pump it may perform badly. However on another day the same company may make its fuel out of a different blend to get the same RON but a different MON. This is done for profit reasons and is why you occasionally get bad fuel even though it is legally rated the same. In the past with high leaded fuels nobody noticed but nowadays high performance cars do notice - as most of us can attest to!!
In America the service stations use the Pump Octane Number or PON rather than RON. this is the average of RON and MON and gives a much better grade, and is also why the American gas always seems not as good as our when in fact it is is the same (and has better quality control). But even this system can be abused by adding octane boosters to poor fuel. The Japanese cars luckily for members of this club use good old RON!!
Below is an approximate comparison chart, these numbers can vary by as much as 2 grades.
RON MON PON
90 83 86.6
92 85 88.5
95 87 91
96 88 92
98 90 94
100 91.5 95.8
105 95 100
110 99 104.5
So whether you use "Super" or "Normal" now you know where these numbers come from. Remember if your car is tuned on "Super" USE IT, if its a normal car chances are using "Super" is a little wasteful of your hard earned $. (Sorry this keyboard doesn't have a pound symbol!!!)
Higher Octain = harder to detonate, ideal for turbo and supercharged applications.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
30-08-2018, 12:46 PM
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
30-08-2018, 12:46 PM #2Hmm tables didn't work.............. Rabs please sort!!!!
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
30-08-2018, 01:34 PM
1990 Eunos Roadster in Mariner DU blue
Cobalt cat back, Decat pipe, 15in Red Rota GT3 alloys, Toyo tyres, Lowered on Coil overs, Red anti roll bars, 14degree timing mod, white dash kit, illuminated side marker lights,
Halo ring headlights, OEM windblocker, Bluetooth streaming HU, Blue leather handbrake and gear lever gaitor, Centre brake/tail light mod, Blue velour door cards, Polished cam cover, Polished front strut bar, 4xheadrest speakers, JDM floor mats, Suede semi dish steering wheel,
good info there Phil
1990 Eunos Roadster in Mariner DU blue
Cobalt cat back, Decat pipe, 15in Red Rota GT3 alloys, Toyo tyres, Lowered on Coil overs, Red anti roll bars, 14degree timing mod, white dash kit, illuminated side marker lights,
Halo ring headlights, OEM windblocker, Bluetooth streaming HU, Blue leather handbrake and gear lever gaitor, Centre brake/tail light mod, Blue velour door cards, Polished cam cover, Polished front strut bar, 4xheadrest speakers, JDM floor mats, Suede semi dish steering wheel,
30-08-2018, 01:50 PM
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
30-08-2018, 01:50 PM #4Thanks Phil.
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
31-08-2018, 05:19 AM
(just don't believe one of them when they tell you the cat you are adopting off them is an angellic saint) [/COLOR]
[SIGPIC][/SIGPIC] [COLOR="DarkOrchid"]That symbol on the side of my door.. Definition by FirebirdPhil 'Translated it means -
"try to overtake - go on give it a go I dare you......." [/COLOR]
I'm not an Outlaw; I'm a Poutlaw! Purple Supras are the bestest! I love purple .. a lot lot lot
purplewitch
31-08-2018, 05:19 AM #7[COLOR="DarkOrchid"]Both Phils are good
(just don't believe one of them when they tell you the cat you are adopting off them is an angellic saint) [/COLOR]
[SIGPIC][/SIGPIC] [COLOR="DarkOrchid"]That symbol on the side of my door.. Definition by FirebirdPhil 'Translated it means -
"try to overtake - go on give it a go I dare you......." [/COLOR]
I'm not an Outlaw; I'm a Poutlaw! Purple Supras are the bestest! I love purple .. a lot lot lot
31-08-2018, 06:42 AM
purplewitch Both Phils are good
(just don't believe one of them when they tell you the cat you are adopting off them is an angellic saint)
... I think you have missed the joke there witchy :laugh:
speedfreek
31-08-2018, 06:42 AM #8purplewitch Both Phils are good
(just don't believe one of them when they tell you the cat you are adopting off them is an angellic saint)
... I think you have missed the joke there witchy :laugh:
'99 Lexus IS200 SE Navigator
[SIZE=3]'93 Mazda Eunos Roadster Turbo[/SIZE]
(Current project)
[SIZE=3]'93 Mazda Eunos Roadster Turbo[/SIZE]
(Current project)
31-08-2018, 07:07 AM
) .... just turn down an opportunity to have a dig at 2Tongues lol
Edited 12-10-2011, 04:42 PM by purplewitch.
[SIGPIC][/SIGPIC] [COLOR="DarkOrchid"]That symbol on the side of my door.. Definition by FirebirdPhil 'Translated it means -
"try to overtake - go on give it a go I dare you......." [/COLOR]
I'm not an Outlaw; I'm a Poutlaw! Purple Supras are the bestest! I love purple .. a lot lot lot
purplewitch
31-08-2018, 07:07 AM #9lol No I didnt.(Phils/Feels - I get it.. now it sounds rude ) .... just turn down an opportunity to have a dig at 2Tongues lol
[SIGPIC][/SIGPIC] [COLOR="DarkOrchid"]That symbol on the side of my door.. Definition by FirebirdPhil 'Translated it means -
"try to overtake - go on give it a go I dare you......." [/COLOR]
I'm not an Outlaw; I'm a Poutlaw! Purple Supras are the bestest! I love purple .. a lot lot lot
31-08-2018, 07:19 AM
purplewitch lol No I didnt.(Phils/Feels - I get it.. now it sounds rude
You just wait till I see you next I will put you over my knee!!
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
FirebirdPhil
31-08-2018, 07:19 AM #10purplewitch lol No I didnt.(Phils/Feels - I get it.. now it sounds rude
You just wait till I see you next I will put you over my knee!!
"Life's goal is not to arrive safely at the grave in a well preserved body. But, rather to skid in sideways........
totally worn out and broken, shouting 'Holy ****, WHAT A RIDE!'"
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