Octane rating of petrol in Ireland?

Pops_20

A few years ago I remember seeing super unleaded at the pumps at Topaz or maybe Shell stations around the country. After watching a doc about ethanol fuels I had a thought today about what choice of fuel we get compared to other countries.

Is 95 all we can get here? Most Japanese imports require 98 or higher as far as I know so can these cars not be catered for properly?

NIMAN

I think I seen a few places that still stock the Super Unleaded.

I used to put ordinary 95 in my MR2, but when I treated myself, and the car, by filling with a tankful of 98, you noticed the difference.

Pops_20

It's a pity they don't have 98 as standard at all pumps. Where can you get 98, is it only at topaz?

Supergurrier

Topaz don't do 98 octane

babybuilder

What is the octane value at Applegreen? Is it the same fuel as topaz?

mullingar

Propane is 110 octane

coylemj

There was threads on this subject a few years ago which I was interested in as at the time I had a 2007 Golf GT which preferred 98 but could do an auto adjust to handle 95. From the research I did I discovered that the addition of ethanol to unleaded (usual content at the pumps is 5%) has the unintended effect of raising the octane rating because ethanol acts as a retardant to spontaneous combustion but ethanol has a lower energy rating than pure unleaded 95 so it's swings and roundabouts because if you buy petrol which is 95% unleaded and 5% ethanol and which has an octane rating of 99 or so, the energy (measured in megajoules per litre) is lower by the addition of ethanol so overall it will make no difference to a car which ideally wants RON 98.

hi_im_fil

There is no brand which advertises selling a petrol of greater than 95ron in the republic. They do sell petrol with 5% ethanol which can increase ron rating but no company will guarantee its any higher than 95. If you have a car which requires greater than 95 ron, it's safer to get it remapped unless it can auto adjust the map to suit.

Pops_20

Yeah i read that online about the ethanol. Interesting how it increases the rating but has a lower energy rating. Kind of pointless really? Apart from the extra resistance to knocking I suppose.

It's kind of unbelievable that 98RON isn't generally available. I would assume that my Glanza won't have any issues as haven't noticed any problems and judging by how many came into the country, I'd say the majority of people aren't too concerned with what fuel they use. In this case there must be a map that adjusts itself?

kirving

Surely any reasonably new car's ECU can adjust to suit without the need for remapping?

coylemj

hi_im_fil wrote: »

There is no brand which advertises selling a petrol of greater than 95ron in the republic.

True, but a few years ago Maxol were claiming that their unleaded (with 5% ethanol) was rated at 99 ron. I stress this was a technical piece on their website if you choose to look it up but as you say, they did not advertise this fact so at no stage was it used to promote their fuel over the competition.

On the energy ratings, this was from Maxol's website also a few years ago, 'MJ' refers to Megajoules per litre and 'E5' refers to unleaded with 5% ethanol....

• One litre of Unleaded has a calorific value of 31 MJ
• One litre of Bioethanol has a calorific value of 21.2 MJ
• One litre of E5 has a calorific value of 30.51 MJ

babybuilder

hi_im_fil wrote: »

There is no brand which advertises selling a petrol of greater than 95ron in the republic. They do sell petrol with 5% ethanol which can increase ron rating but no company will guarantee its any higher than 95. If you have a car which requires greater than 95 ron, it's safer to get it remapped unless it can auto adjust the map to suit.

Does this mean that petrol with ethanol is less efficient and basically crap fuel?

Pops_20

Surely fuels with an octane rating of 98-100 will only be beneficial in terms of resistance to knocking on high compression engines or modified cars with high boost engines, not your average N/A car?

Supergurrier

hi_im_fil

babybuilder wrote: »

Does this mean that petrol with ethanol is less efficient and basically crap fuel?

A high ethanol content will mean you need more volume to produce the same amount of energy when compared to a pure petrol. Not crap but not as energy dense as 100% petrol

hi_im_fil

Pops_20 wrote: »

Surely fuels with an octane rating of 98-100 will only be beneficial in terms of resistance to knocking on high compression engines or modified cars with high boost engines, not your average N/A car?

Yes you will only see a major benefit on high compression or boosted engines. Run of the mill cars will see no noticeable difference.

jimgoose

coylemj wrote: »

True, but a few years ago Maxol were claiming that their unleaded (with 5% ethanol) was rated at 99 ron. I stress this was a technical piece on their website if you choose to look it up but as you say, they did not advertise this fact so at no stage was it used to promote their fuel over the competition.

On the energy ratings, this was from Maxol's website also a few years ago, 'MJ' refers to Megajoules per litre and 'E5' refers to unleaded with 5% ethanol....

• One litre of Unleaded has a calorific value of 31 MJ
• One litre of Bioethanol has a calorific value of 21.2 MJ
• One litre of E5 has a calorific value of 30.51 MJ

Nitromethane runs about 12 Mj/kg, so a JDM Glanza is nearly three times faster than a 'Fueler, innit!

babybuilder

hi_im_fil wrote: »

A high ethanol content will mean you need more volume to produce the same amount of energy when compared to a pure petrol. Not crap but not as energy dense as 100% petrol

Always figured that apple "red" was crap fuel!

jimgoose

babybuilder wrote: »

Does this mean that petrol with ethanol is less efficient and basically crap fuel?

Yes. And that would be all of it - all U95 in Irish forecourts is at least 4% ethanol. Which is why I run TC-W3.

Special Circumstances

jimgoose wrote: »

Yes. And that would be all of it - all U95 in Irish forecourts is at least 4% ethanol. Which is why I run TC-W3.

How long have you been at that, any verifiable benefits? Tempted... If any engine would benefit I reckon a flat four would be happy with some extra ucl. Chandlery or online?

Special Circumstances

Pops_20 wrote: »

Surely fuels with an octane rating of 98-100 will only be beneficial in terms of resistance to knocking on high compression engines or modified cars with high boost engines, not your average N/A car?

May be that several subaru NA models suffered on this fuel, not the complete fubar that detonation caused for the turbo jap imports, just seems to be a few models in Ireland / UK with hesitation issues which have been rumoured to be due to very cautious knock detection.


Caution... online rumour only source of info!

http://www.honestjohn.co.uk/forum/post/index.htm?t=59112

jimgoose

Special Circumstances wrote: »

How long have you been at that, any verifiable benefits? Tempted... If any engine would benefit I reckon a flat four would be happy with some extra ucl. Chandlery or online?

Chandlery. After about six months, quieter and less oil consumption, and very slightly better fuel economy. I run 1.9ml/l.

Del2005

babybuilder wrote: »

Does this mean that petrol with ethanol is less efficient and basically crap fuel?

It's crap fuel because the bio part is produced from stock that could feed people, is produced in mono cultures that destroyed natural habitats and we're lucky that we never got E10 or E15 as that stuff destroys plastics (granted not a major issue for most cars but it's done series damage to motorcycles) , but it's bio so the greens think it's good!

jimgoose

babybuilder wrote: »

Always figured that apple "red" was crap fuel!

I don't trust any of those mickeybollocks brands. Lot of tankers turning up at 4am driven by fellas with Monaghan accents, I reckon.

coylemj

jimgoose wrote: »

I don't trust any of those mickeybollocks brands. Lot of tankers turning up at 4am driven by fellas with Monaghan accents, I reckon.

This tread is about petrol, not washed diesel.

jimgoose

coylemj wrote: »

This tread is about petrol, not washed diesel.

I know exactly what this thread is about.

flexcon

Sorry if I dig up an old thread but circle
k miles plus 97 is a minimum 97RON rating. I emailed them and they kindly came back to clarify that it is indeed 97

Not trusting their word totally I eventually came across this which seems to verify again

https://www.circlek.ie/wp-content/uploads/2018/05/milesunleaded_97.pdf

biko

Thanks, but old thread lock...