Discussion
IIRC it retards the ignition so the fuel is compressed more before the spark, this gives a better bang and more power.
There have been some independent tests where they tried super VS normal on various cars and generally got a gain in power and economy. The gains were more apparent on higher performance cars.
Porsche says their engines are tuned to run best on 98 so lower octane ratings can reduce power.
Whether anyone can actually feel the difference on the road is a different matter!
There have been some independent tests where they tried super VS normal on various cars and generally got a gain in power and economy. The gains were more apparent on higher performance cars.
Porsche says their engines are tuned to run best on 98 so lower octane ratings can reduce power.
Whether anyone can actually feel the difference on the road is a different matter!
Better fuel, ie VPower etc did make a difference in my old Impreza when i had it. Most Subaru owners will back this up. But as has been said, it tends to be in performance cars that the difference is noticed. I doubt Gran in her 2001 Fiesta will gain anything apart from a lighter purse!
Kit2Kar said:
I have found that an engine runs alot smoother on fuel from BP/Shell etc, I personaly will not use supermarket fuel in any of my cars.
Now i thought all fuel came from the same refinery....? Sure the v power may have an additive in it but normal fuel surely is the same ?Mike
I can only easily get 97 RON round my way - eek! Is my car now shagged ;-)
As I understand it, all the petrol types have the same calorific value, so the same energy contained within them - the RON rating only relates to their ability to resist early ignition or knocking. By retarding the ignition for lower RON fuel, the engine doesn't get the most effective combustion point to engine position possible, hence the lower power/fuel economy?
I am not convinced by the high end fuels and get no better performance from Shell V whatever over Total 97 TBH?
I'm sure someone much clevererer than me will be along to blow this out of the water soon?
As I understand it, all the petrol types have the same calorific value, so the same energy contained within them - the RON rating only relates to their ability to resist early ignition or knocking. By retarding the ignition for lower RON fuel, the engine doesn't get the most effective combustion point to engine position possible, hence the lower power/fuel economy?
I am not convinced by the high end fuels and get no better performance from Shell V whatever over Total 97 TBH?
I'm sure someone much clevererer than me will be along to blow this out of the water soon?
On a previous thread someone said that a petrol car will back things off for low grade fuel straightaway (makes sense, you'd want it to) but will take longer to slowly turn the wick back up when decent stuff is used regularly. This of course means it's hard to tell the difference in performance (/economy) as the change may be gradual, unless you fill an empty tank with V power and have a garage reset the car's adaptions to factory base settings (i.e. expecting 98RON).
A friend runs his Smart car on V Power and says he can notice the difference and also gets 30-40 miles more per tank.
I did see 5th Gear do a rolling road test to compare diesel fuels and the differences were immediate and significant, never seen one done for petrol though.
A friend runs his Smart car on V Power and says he can notice the difference and also gets 30-40 miles more per tank.
I did see 5th Gear do a rolling road test to compare diesel fuels and the differences were immediate and significant, never seen one done for petrol though.
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