99 octane or 98

jake

I AV MOSTLY BEEN BEATING
Feb 2, 2003
2,666
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rochdale
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lol do any of you guys using these higher ron fuels actually have your cars mapped on higher ron fuel? personally i would only ever bother with 99 ron etc if i owned an import

From a tuning point of view yes it's massive,

If your cars mapped then your better of with a higher Ron fuel you can run more timing,

Log your car after a full tank of morrisons fuel then log after a tank of v power and look at your cf figures guarantee the ecu will pull timing,

It's like £4.00 a tank different
 

Nath.

The Gentlemans Express
Jan 1, 2006
8,620
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EASTLEIGH, HAMPSHIRE
Ive given the Vpower diesel a try and I found it seemed to tick over a little quieter but that was all. I tend to full with it in the summer when the windows are down.

Vpower diesel has a touch more cetane than regular derv.

Each to their own but +40 BHP?

Realy???????
 

Jimbobcook

Moderator
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Nov 24, 2012
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Does anyone have a mapped car but uses 95... For example they don't have great access to the premium stuff like me lol one thing that's put me off getting a remap...

Sent from my HTC One X using Tapatalk
 

Roganjosh

Active Member
Jan 1, 2013
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I mean it from an aspect of people on a standard map using 99 ron, or people who mapped their cars on 95 ron yet drive around on 99 ron when its not even mapped for that fuel anyways
Or probably even more common people go for a remap so that day splash out the extra few quid on 99 ron then after the remap go back to good ole asda fuel day to day
 

LeonCR

Active Member
Oct 22, 2009
2,389
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Do you guys realise that even that standard map adapts to better fuel ??
 

cupra fan

Full Member
Nov 30, 2001
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norfolk
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If shell is 99 octane now, can't see the point of using Tesco! as shell presumably has a better additive package,hence better for the car or is it just a case of which garage is more accessible! (both the same)
 

_chris_

Active Member
Jul 6, 2008
349
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in the car
Surely the fact that the mk2 cupra's are quite high compression for a turbo car, its better to put the 99 octane in. even with them being direct injection.

I know i wouldnt want to run 95octane on a stage 1, 2 or 2+ curpa.
 

george g

Active Member
Aug 6, 2013
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Just to put this debate in perspective;

The cars as standard are likely designed to run on anything as low as 90 RON petrol... thats the standard in Japan and many places around the world. Premium fuels (most of europe, including UK) average around 92-95 RON and anything higher is seen as super premium...

http://en.wikipedia.org/wiki/Octane_rating

Im NOT disputing that the cars ECU can adapt its timing to suit the fuel - it is certainly well within the realms of modern ECU's to do this, OR that there is no performance gain from using 99 RON fuel but whatever fuel you use it is worth remembering that the standard engines will still run fine on 90 RON fuel.

How much is hype driven by marketing and how much your cars performance is effected can be a very personal opinion - Real world performance is something that is very hard to quantify as there are so many variables.

Obviously this is purely for the standard engine... once you start to modify it, then that opens up all kinds of avenues and the answers really depend on how good the tuner was, how much they understand and how specialized you asked them to be...

What I'm trying to say is that this debate is useless as the engine output is completely subjective to the individual car and conditions its being run in...
 

M6ccy69

My Other Beast Is a R1
Nov 18, 2006
262
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Accrington
One thing I noticed about m99 is that it doesn't seem to burn as clean, back of the car gets covers in black spots a lot quicker

Ive defo noticed this!!!! Not so recent tho! Altho not sure which fuel it could be! I put either bp ultimate in or vpower. Wife doesnt understand the difference so therfore she can put anything in!!! [:@] do tell her to please put high octane in ;)
 
Jun 26, 2008
1,299
1
Just round the corner.
You get 40 BHP from an extra 2 octane?

WOW! that's an unbelievable claim........................

Personally, having given it a good go (really wanting it to make a difference) I came to the conclusion that it was all placebo. Unless you have massive mods designed to take full advantage of it.

On a stock engine or just a basic remap I really couldn't tell at all. Well, I could feel the difference in my wallet.

I haven't claimed 40 bhp extra, I said I had lost 40 due to the map settings. The map setting on 2+ is to run on 99 RON.
The software is tailored to specific Octane ratings. I have a 2+ map to run on 95 octane, but won't get full power.
Stands to reason that if a map is asking for a certain octane rating, which it not receiving then it won't make that power level.
 

Madder

Active Member
Feb 11, 2014
21
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Kings Lynn,norfolk
Tesco buy there fuel from shell or bp I don't think we have any other distilleries so are they going to sell there best stuff or the stuff they don't want hence cheaper supermarket prices?
 
Feb 6, 2014
1,323
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Lincoln
The fuel as it leaves the depot is the same, often retailers share fuel and there are various share agreements between them. What the real difference is, is the additives added prior to sale. This is most often in the lorry on route to the pump. This is where the main differences between branded fuel and supermarket fuel is.

For a stock car, 95ron is safe. You will not be making the quoted power output, that could be between 5-15% less then the manufacturer states (can't quite remember the source of that). Just like mpg figures. Our alfa clearly states in the manual that to get the 155ps the *car* can achieve, 98ron or more is required. The wife doesn't care though.... she just likes how it looks and sounds (and that it is 'nippy'). Most wouldn't be able to notice the difference of 5% or so. 5% loss on an average car producing 100ps is still making 95ps. But up to 15% loss on 240ps is another matter....

For the sake of a few quid, i use Vpower Nitro. The garage is one the way to work (supermarkets are not) and my car is mapped.

Bottom line is that super unleaded fuel will not boost your power, it will give you what you were supposed to have in the first place.
 
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big eck

Active Member
Aug 11, 2005
3,976
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Falkirk, Scotland
I use a mixture of shell or M99, mostly M99. When G logged mine it was ran on M99 and was running spot on and still made over 370bhp on the rolling road.
 

Madder

Active Member
Feb 11, 2014
21
0
Kings Lynn,norfolk
It's not all about the engine and what's been done too it as when I first started using the roads I had a moped all fuels other than optimax would make it run but just normally where as optimax turned it into a banshee it used to scream proper little traffic light racer so when tesco bought out there new 99 Ron as at the time optimax was 98 I thought great filled up and oh my god it ran worse than with cheap super market fuels so my trust is with shell and it's been proven to me :)
 
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