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Discussion Starter #1
So the manual i think recommends 95 Ron.

I've been running mine on 98 Ron. Because i just assumed that's what it would need (my car needs to so i'm used to it and know where the cheap stations are).
And australian fuel is well known as being dirty and poorly tested.
But apparently the bike will be happy with 95?

what do you all run?


Here's a handy chart (RON):

American Regular: 87
American midgrade: 89
American Premium: 92.5

EU & UK Regular (called premium in the UK): 95
EU & UK Premium (Called Super in the UK): 97.5
EU & UK Super/(Called Ultimate or V-Power in the UK): 98
EU only (unknown name): 102

Australian Regular: 91
Australian Premium: 95
Australian Super/Ultimate: 98



Sources:
https://www.fueleconomy.gov/feg/octane.shtml
it should also be noted that american 'ron's are actually an average of the RON and MON called a AKI, so US 87 is probably the same as 91.
https://www.drive.com.au/motor-news/everything-you-need-to-know-about-unleaded-petrol-119462
 

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American premium. That's the highest Octane # you can get in US gas stations (as far as I am aware). At least the Duke does not sip as much gas as my Camaro SS...
 

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I asked the service manager when doing first service ( I ran my last 2 VFR’s on “VPower” & felt it made a difference, smoother & a bit more oomph, both had around 100,000 miles on them).
He said the engine is designed to run std UK/EU fuel & the improvement on my old bikes would have been from cleaning agents in fuel, which a new clean Euro 4 engine shouldn’t need?

Any thoughts?
 

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Discussion Starter #7
I asked the service manager when doing first service ( I ran my last 2 VFR’s on “VPower” & felt it made a difference, smoother & a bit more oomph, both had around 100,000 miles on them).
He said the engine is designed to run std UK/EU fuel & the improvement on my old bikes would have been from cleaning agents in fuel, which a new clean Euro 4 engine shouldn’t need?

Any thoughts?
That sounds right. I think one of the consumer magazines did a test and concluded that it MIGHT give you a small ecomony boost, say 5-8% but if you're paying 10%+ more for the stuff you'll be going out backwards.

In the old days of carburetor, i had to change the needle to match the fuel i was using.

then electronic ignition came out, and i understood it wasn't overly flexible and required a remap to get the best out it if you changed fuels.

nowadays the ecu will be able to adjust a lot for the range of octanes, but you'll get the 'best' result from a specific octane. And that's where i'm stuck: the manual in Australia (P.273) says Super unleaded, then gives the RON for premium unleaded.

i'll have to look up the standard...
 

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The problem with lower octane number would be detonation and the horrible damage it can and will cause an engine, if sustained. Melted pistons with holes punched through their crowns is a sight to behold. Detonation doesn't do any good to bearings as well. Otherwise, using a good quality, clean fuel should be fine, even if it is of lower octane. Higher octane will allow advancing the ignition, which is important, mainly, in high rpm.

In the good old days, detonation used to pose much more of a problem, as a lot of the parameters were "built into the engine" and had a very limited range of fixed adjustment. it ran a single, simple 2D ignition curve that managed the degrees of advance as a function of RPM. That means that you had to tune an engine to perform best based on the worst case scenario and sacrifice other operating points. For example, the your max ignition advanced for a high revving, high compression engine was based on performance in the upper rev range. This would sacrifice low and mid range power generation.

With today's ECU controlled fuel injection and ignition, there is much less of a problem, as the ECU can react to pinging (and other sensor data) and very quickly adjust parameters to avoid it (mainly by retarding ignition or changing fuel amounts or air/fuel ratio). The main issue would be that an engine designed to produce a certain power output on a high octane fuel will, most probably produce less.

In its new turbo charged gasoline engine, Mazda provides two power output numbers, one for regular fuel and one for premium. The number for regular is significantly lower than for premium. Torque, BTW, is the same for both. That said, Mazda allows use of any fuel with a minimum octane number (I think it is 83). That means that the engine management system has wide enough adjustment range to ensure safe and reliable operation across the entire range.

This long write-up in not condoning the use of lower octane fuel. I am also not fully aware of the design parameters and range of available adjustments of our specific Duke 790 engine. That said, I would venture to guess (and this is ONLY A GUESS) that using a lower octane fuel will not be damaging.
 

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And another comment:

There are two main ways to determine Octane number of a specific gasoline fuels. RON (Research Octane number) and MON (Motor Octane Number). MON will always be lower than RON, by a significant number. Europe and US are not using the same system to designate octane numbers. The way to determine the Octane properties are the same, but the number presented is different.

In Europe, gas stations describe different types of gasoline based on their RON rating only. In the States the descriptions look a lot like RON, but they are not. In the United States gas stations describe the types of gasoline based on the Pump Octane Number (PON) or AKI (Anti-Knock Index). That number is the average between RON and MON [(RON+MON)/2].

If a fuel is 98 RON then it will be 93 PON -> 93 PUMP
If a fuel is 95 RON and 87 MON then it will be 91 PON -> 91 PUMP

So we need to take this into consideration while comparing European and US specs.
 

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it should also be noted that american 'ron's are actually an average of the RON and MON called a AKI, so US 87 is probably the same as 91.
In Europe, gas stations describe different types of gasoline based on their RON rating only. In the States the descriptions look a lot like RON, but they are not. In the United States gas stations describe the types of gasoline based on the Pump Octane Number (PON) or AKI (Anti-Knock Index). That number is the average between RON and MON [(RON+MON)/2].

So we need to take this into consideration while comparing European and US specs.
magnets already mentioned it in his first post. Just wanted to reiterate and provide some additional info.
 

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I'm US Premium as well. Usually it's 93 or more. I run the same in the Mustang. I wouldn't even attempt to try the US Midgrade!
 

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In its new turbo charged gasoline engine, Mazda provides two power output numbers, one for regular fuel and one for premium..
You bring up an interesting point, (not to go OT with car bit, but, ) My Fiesta ST turbo-hatchback, says it can run on Regular gas, (I'd never do this), yet on 91 or better, you can press a switch, and get more boost up top, when you need it, adding more HP & Torque, and it is most def. noticeable.
Needless to say, I always fill it with Premium, (91-93 octane), and always hit that button before driving off. :grin:
 

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You bring up an interesting point, (not to go OT with car bit, but, ) My Fiesta ST turbo-hatchback, says it can run on Regular gas, (I'd never do this), yet on 91 or better, you can press a switch, and get more boost up top, when you need it, adding more HP & Torque, and it is most def. noticeable.
Needless to say, I always fill it with Premium, (91-93 octane), and always hit that button before driving off. :grin:
There are more parameters involved, but to simplify it you can say that with the higher octane you are able to advance the ignition more aggressively on high RPM and get more power, without knock. I remember playing with ignition points in the good old days. We would advance until we started to get knocking then retard the plate and leave it there. When we changed mixtures or octane we had to do it all over again...

Pity Ford stopped making the ST variants (and actually anything which is not a Mustang or a truck). I had the Focus ST for three years and it was one nice ride. I hear the Fiesta is even more fun.
 

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Discussion Starter #14
SO I had an interesting conversation with the mechanic when i picked my bike up (unrelated)

And he reccomended not running on 98 RON fuel. The reasoning was that (at least in australia) it is massivly inconsistent when tested depending on when and where you get it. He said it will causing fueling issues or strange problems that ocme and go.
He reccommended 95 RON from BP as he's found it the most consistent accross all places and times.

So i'm going to switch to Australian Premium (95 RON*) and see if the rev hunting at start up reduces this winter.

fingers crossed

*American Premium, EU & UK Regular.
 
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