98-99 Octane Petrol

Supergurrier

Where in Ireland does it ?

No engine knock but would like to start using it if there is anywhere in the west that stocks the stuff.

Thanks

Gumbo

All of Maxol's petrol is E5 which is 98 ron IIRC

coylemj

I don't think you can buy it in the south. E5 has an octane rating >100 as an unintended consequence of adding ethanol to 95 unleaded but the downside is that ethanol has a lower energy rating than pure 95 unleaded so you'll get the octane boost but lose out on overall energy.

I think the big filling station on the way into Sainsburys in Sprucefield sells super.

Edit: Correction, Maxol E5 is rated at 99, this is from an old post...

From Maxol website, 'MJ' is a megajoule, a measure of raw energy.

• 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

dgt

BP ultimate is 97 octane.... Or look for Texaco super 99.

Both NI only

fletch

Applegreens too

All of our petrol is E5, with a mix of 5% ethanol to 95% petrol. The use of E5 in place of standard petrol, decreases carbon emissions by 3.4%, and the product can be used in all current petrol engines and doesn’t affect the engine warranty.

unkel

kceire wrote: »

All of Maxol's petrol is E5 which is 98 ron IIRC

That's what I used to think, but this is not true!

E5 is only RON96. You can easily calculate this yourself - E5 is:

95% RON 95 petrol
5% RON 113 ethanol

See this thread

coylemj

Unkel, I'm not saying you're right or wrong but that thread that you point to simply has you saying in the last post that E5 is RON 96 but you don't don't quote a source for your claim. Quoting yourself is hardly concrete evidence to support a claim.

In the same thread (post #40), you say the following....

unkel wrote: »

Any E5 (based on 95% RON 95) is octane 99.

http://www.boards.ie/vbulletin/showpost.php?p=79175893&postcount=40

Maxol also say it's 99......

http://www.maxol.ie/index.php?option=com_content&view=article&id=144&Itemid=292

Supergurrier

Is 1-2 Maxol stations that stock it near me will try afew fillups on it

langdang

Supergurrier wrote: »

Is 1-2 Maxol stations that stock it near me will try afew fillups on it

It's E5 practically everywhere AFAIK. Just Maxol made a thing of it when it arrived first.

coylemj

Maxol were first of the major chains, they rolled it out to all their filling stations after a trial following which they stopped selling 100% unleaded then I think one of the Green ministers made it mandatory in all unleaded, might have been Eamonn Ryan who had the job Pat Rabbitte is in now.

unkel

coylemj wrote: »

Unkel, I'm not saying you're right or wrong but that thread that you point to simply has you saying in the last post that E5 is RON 96 but you don't don't quote a source for your claim. Quoting yourself is hardly concrete evidence to support a claim.

I see where you're coming from. My point is that claiming E5 has an octane of RON99 because it is a mix of 95% RON95 and 5% ethanol is a false claim

Ethanol is RON113 (or so, some sources such as wiki claim as low as RON108), so the combination has (95*95 + 5*113) / 100 = RON96 at best

The only way to get a mixture of 95% RON95 petrol and 5% RON113 to be anywhere near RON99 is to add octane boosters. And believe me, that would make that kinda petrol a lot more expensive than what Maxol / Topaz or the likes are charging us for E5

Q.E.D.

coylemj wrote: »

In the same thread (post #40), you say the following....

As I said, I was mistaken before

frozenfrozen

Just to inject some chemistry into this, the ratings are given to fuels based on their behaviour. So the fuel is compared in its performance against mixtures of heptane and 2,2,4-trimethylpentane. Heptane has an octane number of 0, and 2,2,4-trimethylpentane has an octane number of 100.

So a fuel with an octane number of say 97 is as efficient a fuel as a mixture of 97% 2,2,4-trimethylpentane and 3% heptane.

Since lead has been phased out as a method of increasing octane number, the fuel we get has undergone "octane boosting" as someone said previously. In Brazil they simply add ethanol to the petrol to increase the octane number because they've got so much sugar cane, they can't do that here as it would be too costly, so they use a few different methods, wherein they basically just heat up the petrol until it breaks up chemically and then reforms with a higher octane number.


....:D

Joe 90

So what do the guys in Ireland who have things like JDM Evos which were sold in a market where genuine 100 octane do?

TestTransmission

Joe 90 wrote: »

So what do the guys in Ireland who have things like JDM Evos which were sold in a market where genuine 100 octane do?

I assume they can get them mapped to compensate?

Seweryn

Joe 90 wrote: »

So what do the guys in Ireland who have things like JDM Evos which were sold in a market where genuine 100 octane do?

Why JDM? Even my 1980 Porsche 924 required 98 Octane fuel. It ran reasonably OK on the Irish standard juice though.

Matt Simis

Seweryn wrote: »

Why JDM? Even my 1980 Porsche 924 required 98 Octane fuel. It ran reasonably OK on the Irish standard juice though.

Thats why, actual JDM stuff isnt designed to tolerate lower octanes (as they arent designed for outside Japan), much like if you bought that Porsche to Russia.

Seweryn

Matt Simis wrote: »

Thats why, actual JDM stuff isnt designed to tolerate lower octanes (as they arent designed for outside Japan), much like if you bought that Porsche to Russia.

I do have a JDM car at the moment, but it is nothing out of standard, i.e. normally aspirated typical engine. Will check the manufacturer's requirement for octane rate as a matter of interest.

L1011

unkel wrote: »

I see where you're coming from. My point is that claiming E5 has an octane of RON99 because it is a mix of 95% RON95 and 5% ethanol is a false claim

There is no guarantee that the base petrol is RON95 to begin with.

Particularly as only Maxol make any claims to as to the octane rating of their E5 - all others just sell it as being 95. It can be anywhere higher than 95 but its not guaranteed to be, just not lower than 95.

unkel

MYOB wrote: »

only Maxol make any claims to as to the ethanol rating of their E5

All E5 has an ethanol rating of 5%

Perhaps you mean the octane rating?

MYOB wrote: »

It can be anywhere higher than 95 but its not guaranteed to be, just not lower than 95.

Indeed. If the petrol used in E5 is RON95 then E5 itself is RON95.5 - RON95.9 (depending on what octane the ethanol is, I've seen it ranging from RON106 to RON113 on a quick google)

If the petrol used in E5 has a higher octane, then the E5 itself could have a higher octane than RON96

Funny thing is that everybody on the internet just assumes all E5 is RON99 (I was guilty of this myself)

L1011

unkel wrote: »

All E5 has an ethanol rating of 5%

Perhaps you mean the octane rating?

Yes. Will edit...

Del2005

coylemj wrote: »

http://www.boards.ie/vbulletin/showpost.php?p=79175893&postcount=40

Maxol also say it's 99......

http://www.maxol.ie/index.php?option=com_content&view=article&id=144&Itemid=292

No they don't. They say

The Octane rating of E5 is higher and has been measured at 99.

Which means that it can be anything from 95 to 99.

coylemj wrote: »

Maxol were first of the major chains, they rolled it out to all their filling stations after a trial following which they stopped selling 100% unleaded then I think one of the Green ministers made it mandatory in all unleaded, might have been Eamonn Ryan who had the job Pat Rabbitte is in now.

It wasn't any of our leaders who made all fuel E5. With the limited sales of E85 cars the EU decided it would be better to get 5% of all cars on fuel from "green" sources than a tiny number on 85%. Similarly in the USA they've pushed all fuel to E10

Joe 90

Seweryn wrote: »

Why JDM? Even my 1980 Porsche 924 required 98 Octane fuel. It ran reasonably OK on the Irish standard juice though.

I said JDM because 100 octane is available there. I would assume that official imports would be EU homologated, hence would be OK on 95.

vincenzolorenzo

So a higher octane number can mean less energy per kg of fuel-reduced mpg but higher power available when you put the foot down?

Have I got that right or am I misunderstanding it?

ljpg

Joe 90 wrote: »

So what do the guys in Ireland who have things like JDM Evos which were sold in a market where genuine 100 octane do?

i own a jap import evo since 2007,never re-mapped,not long after buying it i booked it in after a rolling road session with martin tracey at westward enginnering,the ecu was pulling it back at high rpm on the standard 95 crap,martin recommended i run it on maxol e5,after covering 65k miles and a few quarter mile drag race days i can honestly say i never had a single fuelling issues and shes still going strong!!,e5 gets my vote!

Supergurrier

Thanks for the imput, gonna try 4-5 tanks of it over the next month or so

Matt Simis

vincenzolorenzo wrote: »

So a higher octane number can mean less energy per kg of fuel-reduced mpg but higher power available when you put the foot down?

Have I got that right or am I misunderstanding it?

Basically, though you need a highly tuned or simply highly boosted engine to warrant 100octane fuel. High octane usage when its not needed (ie timing not advanced far enough) has no advantage, just the slight disadvantage of being lower energy. This is the same if its petrol or ethanol based.

SouperComputer

vincenzolorenzo wrote: »

So a higher octane number can mean less energy per kg of fuel-reduced mpg but higher power available when you put the foot down?

Have I got that right or am I misunderstanding it?

Octane number, by itself only represents the relative resistance to knock. It has no bearing on the energy density whatsoever. Typically higher octane fuels burn in a more controlled manner, often but not always slower. They also require more energy to set off, but that's relative.

There are many different methods to raise octane in a fuel. You can add alcohols such as toluene, methanol & ethanol as well as isooctane, MBTE and others. Some have a greater effect on the energy density of the fuel than others.

Running a higher octane fuel means that you can use more spark advance, more compression or use a larger charge (turbo or supercharger) without fear of knocking, or its evil brother pre-ignition. Nowadays motors have knock sensors that will adjust ignition timing on the fly to prevent knock, the problem is that it can lead to scorched valve seats as they are exposed to the flame front for a longer amount of time. This is especially true if you run a low octane fuel in a car that requires a higher one. Knock isnt really what you need to be worried about, its a torched valve.
Exception being some very aggressive (non factory) maps.