Nope, I'd also never thought at all about what it meant. Just bigger number = better. I've also now gone down a rabbit hole of reading about premium fuel in my car, which has convinced me to try it again!

It doesn't matter what grade the petrol is, if you put it in a diesel, you'll get home considerably later than you intended 

I've only done it the once.

Quote from: Yet_Another on June 23, 2021, 10:45:29 PM
It doesn't matter what grade the petrol is, if you put it in a diesel, you'll get home considerably later than you intended 

You mean "It don't Ron Ron"



John P

Quote from: njee20 on June 23, 2021, 08:45:30 PM
Nope, I'd also never thought at all about what it meant. Just bigger number = better. I've also now gone down a rabbit hole of reading about premium fuel in my car, which has convinced me to try it again!

If there is any truth to it having better/more additives and you're going to strip your engine down to take a look before and after it'd be an interesting experiment but unless you drive a car that is currently 'knocking' it's highly unlikely you'll notice any difference, especially with modern computer controlled engines.

Obviously forums tend to be full of extreme opinions, are they're split between "OMG throttle response was awful when I ran 95 RON", "power was down 10% when I used 95" and "I don't notice any difference". How clever the knock sensors are to actually respond to a pre-emptive knocking in response to a lower grade of fuel... no idea. I don't notice any knocking. But then I only fill the car up once a month, so I don't mind trying a few tanks of super unleaded to see if it makes any difference. Should get my son to nursery 3 seconds quicker 

Remember the days when you didn't need to buy expensive petrol to make your car go faster.

You could buy self-adhesive stripes from Halfords for a couple of quid, stick them to the bodywork and, Hey Presto !

Quote from: joe cassidy on June 24, 2021, 11:27:53 AM
Remember the days when you didn't need to buy expensive petrol to make your car go faster.

You could buy self-adhesive stripes from Halfords for a couple of quid, stick them to the bodywork and, Hey Presto !

Nowadays you just colour all the windows black, and slip a large coffee tin over the exhaust pipe.

Yeah go for it, if the detergents are better in higher grade fuels you'll give everything a clean out if nothing else.

But... car forums, especially tuner forums... 
Based on the comments you've put in your post I'd wager most of the people who notice a difference either have a sports car that requires a higher grade fuel anyway or more likely have cars that have had the ECU messed with a.k.a tuned so changing fuels might cause a performance decrease. If they're actually measuring a 10% decrease they've got some kind of tuners setup.

Having had the misfortune of driving behind many 'tuned' and modified cars as they stamp on the accelerator to race to the red light or traffic jam up ahead and smelling the uncombusted-petrol laden exhaust coming out the back I'd also wager they don't really care about proper tuning and pouring money down the drain  so I'd automatically take any "my performance increased/decreased" comments made with an unhealthy dose of salt.

Yes, that was entirely my rationale, much raising of eyebrows at some of the claims!

It's a Golf R FWIW, so moderately tuned, but not exactly super car status! Interestingly it seems to vary between individual vehicles whether the minimum fuel is 98 or 95 (itself the topic of much infighting on the forums it seems!), and I've not actually checked my own one! VW definitely recommend 98 though. I foresee zero difference.

Didn't we all used to put Redex in our tank? Yup. And did we notice any difference? Nope. For years I put unleaded petrol in a car that was only supposed to use leaded, and it seemed quite happy on it. I think car engines are more forgiving than the manufacturers try and make out.

Cheers,

Chris