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UK & Ireland S2000 CommunityDiscussions related to the S2000, its ownership and enthusiasm for it in the UK and Ireland. Including FAQs, and technical questions.
I'm not sure I buy into the discernible differences with these fuels. Don't get me wrong - I still get seduced by the marketing and sometimes treat myself to a tank of 99, but if drive the car having not filled for a while, can I tell by the driving experience which fuel is in there?? Nope
I'm curious what the UK/EU Honda owners manual specifies for the recommended and minimum (without damage) RON octane.
North American recommended Pump Octane (PON) is 91 with a minimum of 87 without damage but at a loss of performance (and the knock sensor working overtime!). PON here is the average of Research and Motor Octane numbers (RON+MON)/2. Shell 93 (PON) corresponds to RON 98. PON-100 "race fuel" is available in some locations (and in drums).
Fuel Recommendation
Your vehicle is designed to operate
on premium unleaded gasoline with a pump octane of 91 or higher. Use of
a lower octane gasoline can cause
occasional metallic knocking noises
in the engine and will result in
decreased engine performance. Use
of a gasoline with a pump octane less
than 87 can lead to engine damage.
(emphasis added)
I didn't notice any performance changes when running in areas where "only" 91 octane is available.
In Europe, gas stations describe different types of gasoline based on their RON rating. It is typical to have 100, 99, 98, 97 or 95 RON with prices varying accordingly. In the States the descriptions look a lot like RON, but they are not.
Pump gas
In the United States gas stations describe the types of gasoline based on the Pump Octane Number (PON). That number is the average between RON and MON. This causes many problems.
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
Is American fuel quality bad after all?
No, not at all. Contrary to popular belief, fuel quality in the States is as good as anywhere else in Europe. Most Americans think that because they are running 91 octane fuel, their engine will blow up. It is the same as if they were using European 95oct fuel.
In our website you will find RON ratings required for each remap stage.
98/100 RON means you will need to use 93 PON in the States.
95 RON means you can use 91 PON in the States.
Everywhere else in the world, 98 RON and 95 RON gasoline usually are fit.Anything lower then that and your modern engine will have a lot of trouble adjusting, even on the stock calibration.
Still curious what Honda recommends for the S2000 in those areas using "inflated" octane ratings.
Few drivers and fewer cars move between North America and UK/EU so Pump Octane vs Research Octane may cause minor, initial confusion for travelers renting cars outside their normal area but not problems. Modern engines usually run fine on 87 PON and Honda states it's the minimum safe octane. The label in the fuel access door notes "Premium Fuel Required" or words to that effect which should handle all areas especially for those not obsessed with small differences in numbers like 91 or 93 here and 95 or 98 elsewhere.
Our manual and also the fuel door sticker says 95 RON minimum.
I only use ~105 RON race fuel (also called E85) in mine, it's available on almost all gas stations around here in Sweden
Our manual and also the fuel door sticker says 95 RON minimum.
I only use ~105 RON race fuel (also called E85) in mine, it's available on almost all gas stations around here in Sweden
See on the inside of my fuel cap it says "Use 98 Ron" 00 UK car
Learned today I can run my car on Ethanol (E85) without tuning or bigger injectors or refitting every rubber fitting. In Sweden, anyway. And guys pay big bucks for FlexFuel vehicles.
The octane notice inside my fuel cap is missing. But there is a notice inside the fuel door. Darn iPhone turned these 90° but you get the idea.
Thanks for the pic Andy, I wonder if the early models had different ignition map then.
And as for Chuck, not sure if you are ironic? Of course you need to re-tune.
But it's not much more than that except maybe injectors since stock probably will be to small, especially if you have other mods as well.
05-09-2018, 02:04 AM
