Super Unleaded V

[davebirl 0]

The sticker inside my fuel cap read "recommended 98 RON" All fuels here in the South of Ireland are either 95 or 97 Octance.

 

Got myself some NOS's octane boost, supposed to up octane by 7points.

 

See thread from Vage Site

 

http://cars.vage.ie/invision/index.php? ... bf0c84ca8e

 

Tried it in my VR6 along with a full tank of Texaco Super unleaded 97 octance and felt really quick. Also disconnected the battery for an hour after filling up. Then drove 300 miles to truly test her out. Well impressed. I have kept 2 bottles for the next rolling road and track day.

 

Got the stuff from http://www.motorspeed.com, £12 sterling a bottle.

[thorpey 0]

sounds a good idea will try octane booster myself

[thorpey 0]

i thought i would experiment with lead replacement fuel by adding an octane booster to optimax petrol and i must say there has been a great improvement not only is the car a bit quicker but the car feels smoother too i think this is the way i shall do things now,although more expensive it seems worth it

[Guest]

ooo dear... this could gt expensive... putting octane boosts on every fill up lol maybe ideal for the summer days when you wanna have some fun on a country road.

[Fat Tony 0]

Got this from here

 

http://www.ciao.co.uk/Shell_Optimax_Pet ... ew_5329606

 

Because Optimax is more refined it burns much cleaner and hence, you get a better MPG. This opinion is obviously tying to my car; other people may get different results. The "Optimax" effect will not happen overnight. To really feel a difference you'll have to run it for at least 3000 miles.

 

However, please don't be fooled that the higher octane rating the better it will be for your car! This is a fallacy. Most UK cars runs on 95 RON, using a higher octane rated petrol will make no effect on your car's performance. If higher octane ratings make a car perform better then 95 RON petrol would have been phased out a long time ago! If you wish to know more then read this bit. If not go to the next paragraph. Octane can withstand pressure well, Pentane cannot. When petrol is refined a mixture of Pentane and octane is produced. The quality of the petrol is defined in its octane rating (95 RON denotes 95% octane: 5% Pentane. Likewise, if the petrol is extra refined you'll have 98 RON 98%octane: 2% Pentane). Now, if a car is set at 95 RON petrol, in the combustion chamber (where the petrol ignites with the spark plugs causing the petrol to become a gas) the piston compresses the chamber where the gas is. The amount of pressure is enough for the octane in petrol to withstand. So, if you think about it, why put a more expensive petrol in your car if the piston will only apply enough pressure for 95% octane? It won't damage your car, but it won't make it go any faster. However, if you put a 95 RON petrol in a car that is set to 98 RON petrol, the piston will compress the chamber too much and the pentane will push the piston down too early causing a shuddering in the drive. This is known as "pinking" or "pinging". This will damage your car. This is why octane ratings are important. I will leave this part of my review because I believe the point of the website is to educate people with your knowledge. Thank you kindly.

 

Intresting reading I thought. Not sure if the comments are true but knows more than me :)

[Fat Tony 0]

Nowhere in shell's marketing or documentation does it state an Octane rating for Optimax, other than "at least 95", so they are under no obligation to make sure it's any good!

 

The supermarkets often use the big suppliers (obviously they don't do their own refining/blending), but they also often use the "cheaper" supplier chains - and it's when they do this that you have to be worried about the state of your engine...

 

Found this on shells website

 

http://www.shelloptimax.co.uk/jive3/thr ... ageID=1704

 

I prefer optimax over Esso and BP. And Shell gave me an optimax card because I use so much of the stuff ;)

[stevemac 0]

If the octane rating is based on percentages, how come some fuels have an octane rating in excess of 100 ?

[davebirl 0]

So hey Fat Tony, from reading that I really should be using 98 Octane in my VR6 so, as its written on the fuel cap......

 

Never knew using 95 octane could damage it. Going for super unleaded so from now on then!

[Fat Tony 0]

Dave the way I read his opinion was that if your car was designed for 95 and you stick in anything else thats not bright. But reading this both the Vr and the G60 can take either, not sure about the 16v's. Funny how they dont stick a note above the pump saying that one lol Same sticker on the g60's

 

Steve no idea mate as I said, done chemistry at school but we didnt do much more that oil is refined into petrol.

[bcstudent 0]

If the octane rating is based on percentages, how come some fuels have an octane rating in excess of 100 ?

 

For the same reason that some alcohol is 140% proof maybe?!

 

This is some info I found somewhere:

 

"Octane rating [the figure seen at the pump] is an average figure based on two methods of testing fuel. The Research Octane Number (RON) is a calculated number, while the Motor Octane Number (MON) is a measurement of pre-ignition resistance in a specified research engine.

 

(RON + MON) / 2 = pump octane rating."

[K-rado 0]

I have filled up with shell optimax and if I am been honest, it is no way near as good as the BP Ultimate. Fuel econ has slipped away. There is not as much grunt/go. I think it is better over the standard un-leaded but the extra 6p/liter does not addup. Will deffo be going back to the BP stuff.

Shell seems to be to unstable, must have got the dregs of the barrel where as BP Ultimate is 97/8? RON and seems to be more consistent. My2p

[Tempest 0]

Never knew using 95 octane could damage it.

 

Well I wouldn't go as far as that, as the knock sensor will simply retard ignition timing (as the ECU has maps for several octane fuel types, well at least my G60 chips has ;-) ).

 

What baffles me regarding all this RON-stuff, is that GB still doesn't have the 100 octane stuff they sell on the continent (i.e. V-Power by Shell, and Aral/BP's Ultimate !). I'm beginning to wonder whether this whole 100 octane stuff on the continent is just another marketing ploy/redefinition of the octane rating, particularly as BP even hasn't deemed it necessary to rebrand the 100 octane fuel, unlike Shell!

 

Tempest

 

Tempest

[Jim 2]

Ultimate all the way for me :)

[bcstudent 0]

When unleaded was first introduced it was said that the 16v KR engine wouldn't run properly on it without modification. I only put standard 95 octane fuel in mine and it doesn't pink at all on standard timing. It's a bit gutless but I think that'd be the same on any fuel. Occasionally when fuel is cheaper (like now) I fill up on something a little higher rated but it appears to make no difference whatsoever.

[Kevin Bacon 5]

I have filled up with shell optimax and if I am been honest, it is no way near as good as the BP Ultimate. Fuel econ has slipped away. There is not as much grunt/go. Shell seems to be to unstable, must have got the dregs of the barrel where as BP Ultimate is 97/8? RON and seems to be more consistent. My2p

 

That's what I've found aswell. It's too much of a coincidence that prior to a fill up of Ultimate the car ran poorly on Sloptimax, and then all of sudden ran a lot smoother and punchier!

 

Have yet to try Esso Supreme or what ever it's called....

[Timo. 0]

I quite like Texaco Super. But I barely get chance to put that in the VR. I stick with optimax, I tried BP ultimate and it felt no better.

 

I found the G60 loved BP ultimate, hated 95 RON and went well on optimax.

 

T.

[Tekara 0]

Sticking with BT Ultimate, car likes it and thats all that matters. Tried Optimax a few times but car always runs badly afterwards. Same happens when i use Shell diesel in the other car. Im sure its a problem with the garage than Shell in general.

[stevemac 0]

Maybe I'll be having a re-think about what I put in my G60, once it's back on the road. The sticker inside the fuel flap says "minimum 97 RON" & I've been using Optimax. I may try some of this BP Ultimate & Esso Supreme.

[Rob_B 0]

i was under the impression that BP ultimate is manufactured at 97 RON and shell optimax is manufactured at 95 RON and has octane additives added at a later date to make it 98 RON

[Musicman 0]

Optimax is 95 ron with octane boost, which is highly volatile, so by the time it's sat in your tank for a week or two it's probably down to 95 ron. Ultimate is 97 ron, all day long, every day..

The figures quoted originally are interesting, but are completely statistically insignificant I'm afraid.. You'd really need to run some sort of controlled experiment to be confident that an observed 3% difference was anything other than random variance...

As I'm sure you were aware. :)

 

Um. OK.

 

According to the 'shell expert' on their own message board:

 

Petrol in the UK is manufactured to last up to 2 years under correct storage conditions, however we do not recommend storing a petrol for more than 6 months due to the seasonal changes in quality. The misconception of octane loss comes from the fact that butane is relatively high in octane and this highly volatile component is the one which would be lost first on evaporation. However, butane is not the only way of achieving high octane fuel. If Optimax is stored for a long period of time under inadequate conditions, it is not likely that the octane would drop more than 0.5 - 1 ON, and in this respect it is comparable with other brands of petrol.

 

[emphasis added]

 

Elsewhere the 'Shell Expert' says that "Optimax is 98 RON, 87 MON minimum."

[Jim 2]

Annoyingly my local Texaco (basically at the bottom of my road) doesn't seem to sell Super Unleaded as i'd just use that rather than having to make the 4 or 5 mile drive for a tank of Ultimate.

 

This Esso stuff sounds worth a try though! :)

[dr_mat 0]

I read it on the back of a packet of cornflakes, how could it be wrong??

[kongo127 0]

BP Ultimate in Portugal is 100 RON.

And much more expensive!

But i can truely notice the difference!

No pinking at 8deg. timing

Super responsive engine! :angel: :twisted: :D

[STORM 2 0]

I've had nothing but trouble with that new Esso stuff. Tried Optimax, BP Ultimate without any problems but she DIDN'T like the Esso stuff. In fact The Sainsburys low sulphur Super Unleaded is her favourite, and its thankfully quite cheap at 80.9p litre

[andy 0]

I mostly use Sainsburys Super, it feels better and definately runs more economically than on standard unleaded (95 RON) haven't tried BP or Optimax in this one yet.