Fuel Choices

[Time2Fly]

I'm reading the manual and it says it requires E10 (95 RON) at a minimum and E5 (97 RON) is recommended.

The E ratings appear to be octane equivalents of 94 and 97. And the RON ratings are 91 / 94 octane.

So what's appropriate to use? In California I can't purchase above 91.

 

[Ryder]

Sounds like you will be purchasing gallons of fuel additives to increase the octane.

 

[EM12AAM]

I'm reading the manual and it says it requires E10 (95 RON) at a minimum and E5 (97 RON) is recommended.

The E ratings appear to be octane equivalents of 94 and 97. And the RON ratings are 91 / 94 octane.

So what's appropriate to use? In California I can't purchase above 91.

The E ratings are actually the amount of bio-ethanol in the fuel and the important thing is that the car can handle the higher ethanol numbers. As far as I am aware fuelling with a lower octane gas might impact performance but won't damage the car but best to check with your local dealer.

 

[Jincook]

e10/e05 this number just confuses me since I've only fueled my cars 91 unleaded gas for years. Emira is first car that I pay attention to gas cap instructions.. it shows the number that I've never seen before. E10 e05 ??? Only best thing I can buy is 91 at the gas station but do I need add stuff? Vehicle somewhat felt slower? Or less torque after filling it up with 91 at the gas station. Can anyone tell me what to do?? Am I feeding my emira right fuel by giving 91 at the regular gas station? Or should I give it special fuel?

 

[Nick Sticks]

E05 means the fuel has 5% bio-ethanol in it.
E10 means the fuel has 10% bio-ethanol in it.
The problem with ethanol is that older cars, mainly before 2002 don't like ethanol.

Copied from a UK website:
As a rule, drivers of cars registered prior to 2002 are advised not to use E10 in their vehicle, as problems have been reported. And as of 2011, all new cars sold in the UK must be E10 compatible.

If you put E10 fuel in an incompatible car it will still run, but seals, plastics and metals may be damaged over longer periods as a result of bioethanol's corrosive properties. It is a hygroscopic, which means it absorbs water from the atmosphere, leading to condensation in fuel tanks if the car remains unused for long periods of time.

Lotus say:
Except on the Lotus Emira, Lotus recommends to use a premium high quality UNLEADED fuel, meeting EN228 standard. The rating of any fuel should be clearly marked on the fuel pump.
and:
Lower Octane Fuels – The lower octane rating (typically 93 – 94 RON) will result in slightly reduced performance and economy and are not recommended.

Fuel Compatibility | Lotus Cars United Kingdom

Except on the Lotus Emira, Lotus recommends to use a premium high quality UNLEADED fuel, meeting EN228 standard. Find out more.

www.lotuscars.com

 

[ADC]

@Nick Sticks , worth noting he is in the US, so the EN standard probably means little, and the octane rating is expressed differently. 91 in the US does meet the minimum.

 

[Porter]

I'm reading the manual and it says it requires E10 (95 RON) at a minimum and E5 (97 RON) is recommended.

The E ratings appear to be octane equivalents of 94 and 97. And the RON ratings are 91 / 94 octane.

So what's appropriate to use? In California I can't purchase above 91.

US octane ratings are measured differently than those in the EU.

The EU uses RON (research octane number) for their ratings. The US uses the AKI rating, which stands for Anti-Knock Index and is the average of RON and MON (motor octane number). You may see this expressed as "(RON+MON)/2".

E5 and E10 are ethanol max inclusion percentages. Almost all areas of the US have E10 fuel by default, by law.

US 91 AKI is roughly equivalent to 95 RON, and 93 AKI is roughly equivalent to 98 RON.

 

[crestima]

@Nick Sticks , worth noting he is in the US, so the EN standard probably means little, and the octane rating is expressed differently. 91 in the US does meet the minimum.

Very useful information.. Many thanks for that ADC.
Hopefully one day (certainly not in our lifetime) world convention will help align most countries to single standards to avoid having to resort to these types of conversions and applications. One such recent convention agreement was that of the USB-c adapters for many world wide electronic manufacturers to avoid the silly and inconvenient variety of plug adapters. Perhaps one day consumers around the world will be able to drive their cars with a center steering wheel (no right and left configurations), a single measurement standard (Metric vs Imperial), etc, etc, etc. Unfortunately, with the current ongoing de-globalization trend, this doesn't appear to be realistic any time in the foreseeable future.

 

[scc.131.fe]

you're probably right. unfortunately the single measurement standard may be the volt.

 

[Jincook]

Thanks to everyone for your comments and kind responses I guess 91 us is just fine. ^^

 

[scc.131.fe]

91 is just fine, but I've always found that it's useful to know (for my usual near-home fill ups) which gas stations have newer / better underground tanks for less contamination and also which ones usually get more 91/93 on regular delivery schedules. If you want to minimize crud in your tank, don't grab gas from a station that was refilled within the last few hours as the filling process can churn up whatever settles in that tank.

Also, I have the choice locally of 91 octane ethanol-free that is a base fuel with absolute minimum additive pack, or 93 octane with up to 10% ethanol that has Top Tier rated additive packs. For my direct-injection engines I pick the 93 with better additives to try and keep carbon build-up down. For the Emira (rockin' port injection like it's the 90's!) either choice has its benefits.

 

[Julian73]

I'm reading the manual and it says it requires E10 (95 RON) at a minimum and E5 (97 RON) is recommended.

The E ratings appear to be octane equivalents of 94 and 97. And the RON ratings are 91 / 94 octane.

So what's appropriate to use? In California I can't purchase above 91.

The E is maximum ethanol content as is up to 10% in E10 the U.S. standard in pump gas regardless of regular/mid or premium grades. The important thing here is to never exceed E10 and less is best for a given octane. Ethanol content does not correlate to a octane level, other than that Ethanol is a cheap form of Octane booster.

As to Octane, Europe only uses the RON (research octane number) while the US uses an average of RON and MON (motor octane number), with the average technically called AKI (anti-knock index) not the slang "octane". As the real usage situation is the issue of anti knock (anti pre combustion) in an engine under load, not just some anti-burn characteristic of the gasoline. A rough conversion between RON and AKI 98/99 >> 93

A table of approximate conversions of US available unleaded fuels:

• 87 AKI = 91 RON
• 91 AKI = 95 RON
• 93 AKI = 98 RON
• Race 100 AKI = 104 RON
• Race 104 AKI = 108 RON