optimax

[iaint]

I run my rx7 on 97ron mostly and never have a problem and its cheep only 97.5 i do sometimes use v-power but rarely.Doesnt make any difference to be honest.As long as its over 95ron.What you must remember is these engines arent new,we dont have RX8\'s so lower grade fuel will be fine,High grade fuel has not been here that long.

Most of us 3rd gen owners have cars that were designed to run on Japanese high octane fuel - not the lowly UK fuel.  So while high ron is newish over here it\'s old skool in the land fo the rising sun.

One big difference between cheap supermarket fuals and more expensive fuels (so we\'re told) is the additived they put in to them - detergents etc that can help manage carbon deposits etc.

Allegedly.  Onthe other hand it could all be just marketing...

[Prof]

I also read somewhere that if you leave a tank of the higher octane stuff sitting around for a week or two - the octane rating will reduce as the volatile additives do what comes naturally and evaporate.  I presume this is worse in the summer
 
I use 99 RON because my ECU is chipped and came from Japan - where 100 RON is standard.  I certainly do notice if I put lower than 97 octane in it

[trotter]

Always V-Power for me, seems to make her more responsive and faster than Ultimate IMO

[FLAT4MATT]

End of the day it depends on the car, you could always have it mapped to run on 95RON...

Mine is however mapped to run on 99RON (V-Power on the day) and it generally gets Tesco 99 which so far as I can tell makes no difference (and why should it?).

The most important thing is to run it on the CORRECT fuel, so if its a JAP import running a JAP MAP then it\'s really got to be as near to 100RON as you can get.

As far as different fuel with the same RON rating (Shell99 vs Tesco99) I can\'t tell a difference, I don\'t use BP Ultimate as it\'s only 97/98RON and always seems to be more expensive.

[RobbieRX-7]

End of the day it depends on the car, you could always have it mapped to run on 95RON...

Mine is however mapped to run on 99RON (V-Power on the day) and it generally gets Tesco 99 which so far as I can tell makes no difference (and why should it?).

The most important thing is to run it on the CORRECT fuel, so if its a JAP import running a JAP MAP then it\'s really got to be as near to 100RON as you can get.

As far as different fuel with the same RON rating (Shell99 vs Tesco99) I can\'t tell a difference, I don\'t use BP Ultimate as it\'s only 97/98RON and always seems to be more expensive.

I agree with the above. I wish i had mine mapped with 95ron now. Would save me a few quid a year instead of using Vpower.

[moakesr]

V-Power plus octane booster unless I can\'t find V-Power when it gets 95 RON unleaded and two bottles of octane booster.

Exhaust definitely smells different to my daily car, thats for sure :mmmm

[Hayward North]

Do any of you monitor your afr\'s or knock when changing between diferent petrol grades, also are the ron rating ron/mon ?

I run on v-power keeps afr\'s and knock low.
Never run on anything else.

[FLAT4MATT]

Steve - I\'ve never seen any noticeable difference in knock between the two fuels I use (Tesco / V-Power) but they\'re both rated at 99ron (RON should be [Road Octane Number] not RON [Research Octane Number] or MON [Motor Octane Number] but I\'m not sure whether both Tesco and Shell use Road or Research values...)

As far as additives go I know that V-Power has a lot of detergants and Tesco is 5% bio-ethanol but that\'s where my knowledge runs out I\'m afraid

[Hayward North]

Steve - I\'ve never seen any noticeable difference in knock between the two fuels I use (Tesco / V-Power) but they\'re both rated at 99ron (RON should be [Road Octane Number] not RON [Research Octane Number] or MON [Motor Octane Number] but I\'m not sure whether both Tesco and Shell use Road or Research values...)

As far as additives go I know that V-Power has a lot of detergants and Tesco is 5% bio-ethanol but that\'s where my knowledge runs out I\'m afraid

Anyone know the effects of bio-ethanol ? never looked into it so aint a clue, im guessing it makes the ron rating a little higher ?

Also isnt bio-ethanol a recoverd chemical that apparently contains a lot of other chemicals in unknown quantitys ? <---may be wrong here.

I know there are people planing on testing running a rotory on boi-ethanol, i dont yet understand boi-ethernol so ignore my ignorance if im way off here.


Isnt a True Octain rating dun with a calculation on RON vs MON ?

Loads more questions but am gonna restrain myself as i get carried away haha

[Hayward North]

The principle fuel used as a petrol substitute for road transport vehicles is bioethanol. Bioethanol fuel is mainly produced by the sugar fermentation process, although it can also be manufactured by the chemical process of reacting ethylene with steam.

The main sources of sugar required to produce ethanol come from fuel or energy crops. These crops are grown specifically for energy use and include corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses, jerusalem artichoke, myscanthus and sorghum plants. There is also ongoing research and development into the use of municipal solid wastes to produce ethanol fuel.

I googeld it ...........

[FLAT4MATT]

Could the bio-ethanol thing be so they can say it\'s got something a bit \'greener\' in it? No idea to be honest. I can\'t see it being a performance thing...

Yes RON [Road Octane Number] is calculated from both [Research Octane Number] and MON [Motor Octane Number] and is usually the value they use in petrol stations as far as I know.

[FLAT4MATT]

The principle fuel used as a petrol substitute for road transport vehicles is bioethanol. Bioethanol fuel is mainly produced by the sugar fermentation process, although it can also be manufactured by the chemical process of reacting ethylene with steam.

The main sources of sugar required to produce ethanol come from fuel or energy crops. These crops are grown specifically for energy use and include corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses, jerusalem artichoke, myscanthus and sorghum plants. There is also ongoing research and development into the use of municipal solid wastes to produce ethanol fuel.

I googeld it ...........

Basically they use plant oil instead of crude oil, plants suck up carbon dioxide during the process too which is a bonus. The idea is however flawed as by the time you\'ve harvested and processed the oil then transported it the carbon footprint is not much better. :Hammer

Going off topic a bit now though lol

[kev-yorks]

Steve all the fuel in our area comes from the same source whatever they tell you be it shell, bp, tesco\'s, morrisons etc. Take a ride over to simons storage which is on the docks at Immingham and watch all the tankers running out of there its refined at the Conaco plant and piped into the storage tanks at Simons. All they do with the higher octane fuels is put extra additives in particular storage tanks that they draw the higher octane fuels from. We use a couple of tanker loads of DERV a month supplied by a independent supplier who sub contracts to the big suppliers whoever he\'s delivering for its all drawn from the same tanks.
Kevin

[Hayward North]

Shame we dont know what they add or we could premix our own fuel as well as oil

So any idea what they add to increase the octain rating ? ethernol ?

[kev-yorks]

Its supply is controlled but i\'m working on it. As one of our drivers used to deliver it there.
Kevin