97/99 Ron Petrol?

You need 2 things to get the economy and power advantages:
1. A knock sensor.
2. The right adaptive mapping.

This generally means new or large engines, and generally does not include old or small engines.

On really old stuff you can of course just set the timing yourself, but then you'll melt something if you ever use regular fuel again.
 
I don't know why people knock 95 ron as it is a damn site better than what is the norm outside of europe/japan etc.

95 to 99 is never going to be night and day in most cars less worth than 50k.
 
redeye_uk said:
Higher octane fuel gives better mpg and also contains cleaning agents which are good for the engine
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Rubbish. If your car is mapped to accept 91-97 ron, putting in higher is a total waste of time. As for cleaning agents, that depends on the brand. Some like to put all sorts in, but its like using redex on every tank, you will only see the benefit once.
 
D-Ranged said:
Japenese sports cars are mapped to run on 100+ ron fuel from factory so when they come over here and run on crappy 95 then problems arise.

Skylines have knock control on the standard ecu which retards timing if it detects it but detecting it means its already happened and if it keeps happening then the engine will fail.

So thats why everyone with jap turbo cars at least use 99 RON fuel unless they get there car mapped to run on 95 then they use that obviously losing some power at the same time.
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My Soarer (a Twin Turbocharged Japanese "Sports car") is totally happy on RON 95. I will say that the car was noticeably more responsive when running it's advanced timing on V-Power, but it certainly is no slouch on the standard stuff. The general consensus is that'll run on standard stuff quite happily at standard/near standard boost levels.
 
As everyone else has said, depends what it's mapped for.

On a performance engine you'd have it mapped to 99RON and then use the knock sensor for retarding the ignition as appropriate when the fuel has a lower octane rating.

If your car is mapped for 95RON you won't see any performance benefit by putting 99RON in.


Hence why when the Westfield was mapped in the Dyno cell by the engine builder he had it running on 99RON with IIRC some pixie-dust additives too!
 
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There's a great deal of differing opinions on this subject and nothing concrete. My take of it is for some performance cars higher octane fuel is almost vital for the engine to run how it should. For other cars it is beneficial but not essential... and for ordinary i.e 1.2 Corsas there will be no difference.

If your car falls into the latter catergory just filling up from BP or Shell or any other forecourts which make there own fuel would be best. I know people who work for BP and Shell (it's fairly common knowledge anyway) but the oil BP and Shell etc sell to supermarkets is the **** at the bottom of the barrells. They keep the good stuff for themselves. So I just avoid supermarket petrol.
 
I've noticed no real difference with an adaptive ecu, even after cycling several tanks on both 95 and 99 on the current car.
That being said, when I had the Westfield there was a noticeable difference in pick up and mid range grunt using an octane booster (with lead substitute, engine was designed to run on leaded 4 star) over standard pump unleaded.
IMO it all depends on how the car is set up to run.
 
Perywinkle said:
I've noticed no real difference with an adaptive ecu, even after cycling several tanks on both 95 and 99 on the current car.
That being said, when I had the Westfield there was a noticeable difference in pick up and mid range grunt using an octane booster (with lead substitute, engine was designed to run on leaded 4 star) over standard pump unleaded.
IMO it all depends on how the car is set up to run.
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Try doing a hard "Reset" on the ECU. It made an absoultely massive difference to my car.
 
The Swift is mapped for 98ron (says on petrol cap) It's only had v-power put in it by me. (my closest petrol station is a shell)
 
Gaijin said:
No idea tbh, was just a crass generalisation.

I suppose it ultimately depends on whether we're talking stock or aftermarket engine management.

I'm not touching 95 in any case.
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Fair enough - I've run every turbo car I've owned religiously on SUL, but not for fear of things blowing up if I didn't.

My 620ti loved the stuff, the difference was almost night and day. The VXR recommended it, and again the difference between different SUL was noticeable, let alone 95 (I picked it up with half a tank of 95).

On the ST, there is a discernible difference in fuel economy - as much as 7MPG - so I don't bother with 95. It was also reported (although not quite applicable to mine ;) ) that in factory tests, the car made around 215bhp on 95, and 235bhp on SUL - averaging it out to the reported 225, but I couldn't vouch for such a statement, as I don't recall where I read it.

lmfy2k said:
which stations actually have 98Ron fuel?

is it 97 and 99 only?
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BP Ultimate possibly? although I'm not sure - none of the others are 98.
 
MikeHiow said:
Fair enough - I've run every turbo car I've owned religiously on SUL, but not for fear of things blowing up if I didn't.

My 620ti loved the stuff, the difference was almost night and day. The VXR recommended it, and again the difference between different SUL was noticeable, let alone 95 (I picked it up with half a tank of 95).

On the ST, there is a discernible difference in fuel economy - as much as 7MPG - so I don't bother with 95. It was also reported (although not quite applicable to mine ;) ) that in factory tests, the car made around 215bhp on 95, and 235bhp on SUL - averaging it out to the reported 225, but I couldn't vouch for such a statement, as I don't recall where I read it.



BP Ultimate possibly? although I'm not sure - none of the others are 98.
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just checked:

BP Ultimate Unleaded has a minimum Research Octane Number (RON) of 97. Ordinary petrol sold in the UK is 95 RON. The higher octane quality of BP Ultimate Unleaded means that it burns better than ordinary petrol to release energy more efficiently. So it can help your engine to deliver improved performance and better fuel economy, and protect it from the harmful effects of knock.

http://www.bp.com/sectiongenericarticle.do?categoryId=4005571&contentId=7009025
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think il try v-power :)
 
The higher the octane rating, the higher the "anti-knock" properties of the fuel, this allows a higher compression and/or more ignition advance to be used, which gives more power, not the fuel itself.
If the timing is too far advanced on 95 octane then the fuel can ignite before the spark plug fires, caused by the heat and compression, causing pre-ignition- pinking (not confused with detonation which is ignition of unburnt fuel after plug firing). Pinking (pre-ignition) causes hot-spots in the compustion chamber and can melt pistons (the engine "fail" mentioned above). Same applies to too high a compression ratio.

Basically high octane fuel is only of use in an engine with the compression and mapping to use it, if used in one of these cars then you will see a difference ( inside fuel flap of my M3 says "98" due to the high compression of the engine).
Standard "shopping" cars won't see any difference, as they usually don't have the mapping to suit, more economy based (although higher compression engine can be more economical)
The increased economy some people see is usualy down to their engine being able to use more ignition advance on the higher octane fuel, generating more power so less throttle for same speed etc.
But it's not all about octane, it's more about the actual blend of fuel, many tests have been done and although not as high as Tesco 99, Shell V-power usually performs best.
More often Toluene is added to standard fuel to increase the octane, but I suspect V-Power and BP-102 re a different blend as they both smell different to normal unleaded.

Basically use it in high performace/turbo engines, std cars just use cheapest.
 
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