Premium petrol - worth the extra?

Grade_A_Reject

I'm looking more for experience than opinions.

An accountant acquaintance of mine persuaded me to try the higher octane "premium" fuel claiming he gets a 10% better MPG than when using the standard 95 octane fuel.

I've just filled up with Shell Optimax at £1.24 a litre and after 140 miles the fuel computer in my car is showing pretty much the same MPG as I would have got on the cheap stuff.

Has anyone done any scientific comparisons to work out the cost / benefit?

Young_Pretender

In a word: No

I've kept detailed records of fuel consumption over 4 years, 2 cars and about 20,000 miles.
Nissan 200SX Turbo 2.0 modern ECU with knock sensors etc and 25Mpg typical
Toyota MR2 1988 - still a 'modern' engine design with ecu, twin cam etc, 30Mpg typical.

Running between V-Power (or Optimax as it was) and regular 95RON there was never a significant difference in MPG - and I've used my spreadsheet to average out total V-Power Milage vs Total 95 Ron milage, or only MPG after the 2nd tank consecutive of V-Power for example, and nothing seems to tip it into V-Powers favor and certainly not the +5% economy boost you'd need to offset the higher price.

That said I still use the premium petrol on occasions, because I believe that it's kind to older and 'throughly used' engines due to the additives etc.
I don't do that many miles, so I can afford it every few tanks for the 'perceived benefit'.

By the way, I'm not sad!

Grade_A_Reject

Young_Pretender wrote: »

By the way, I'm not sad!

Crunching fuel consumption figures in a spreadsheet as far as I'm concerned is cool.

neilmcl

If you're going to notice a difference it wont be after just 140 miles, you need to go through a full tankful first and then fill up from empty.

Kilty_2

Depends what you drive - if it's a normal car without a highly tuned engine then you'll see no benefit whatsoever.

maninthestreet

I believe 'Fifth Gear' on channel 5 tested these 'premium' petrols a number of years ago, and found them only of benefit in relation to fuel consumption when used in high performance cars such as the Subaru Impreza.

plane_boy2000

I used to run a smart roadster and got better mpg on v power fuel plus i think it ran a little better so the extra cost was worth it, but on other cars I have had I cant really tell the difference.

As others have said - I think it works better for tuned / performance engines rather than run of the mill stuff

vikingaero

It does depend on your car. Generally turbocharged engines will see some benefit whether petrol or diesel. Whether it's worth the price differential is down to your own pocket.

I run our Corsa solely on Shell Unleaded and our Mazda 5 on V-Power Diesel. Previously to that I ran a MINI Cooper S on V-Power Unleaded. The MINI wasn't really a car to drive slowly in and I found the exhaust deposits to be far less on the tailpipe. The Mazda is a low annual mileage car so I'm not bothered about the cost. Compare that to my BMW company car where I fill it anywhere (mainly Tescos) and the exhaust is absolutely filthy black.

For cars that I plan to keep I choose my fuel carefully. In about 3 months the BMW will be gone so I don't really care what I fuel it with.

LandyAndy

maninthestreet wrote: »

I believe 'Fifth Gear' on channel 5 tested these 'premium' petrols a number of years ago, and found them only of benefit in relation to fuel consumption when used in high performance cars such as the Subaru Impreza.

We used to have a Mazda RX-8, which probably counts as a performance car, and the handbook specifically advised against using premium fuels and stated that there would be no gain in performance or economy from using them.

neilmcl

LandyAndy wrote: »

We used to have a Mazda RX-8, which probably counts as a performance car, and the handbook specifically advised against using premium fuels and stated that there would be no gain in performance or economy from using them.

Could that be something to do with the Mazda's wankel engine, perhaps?

DKLS

I always use super unleaded, and Vpower when somone else is paying I haven't noticed a difference in MPG, but then when your sub 25mpg anyway its not worth the hassle of working it out.

The reason why I use it is my car runs like a dogs dinner on normal unleaded and lacks any punch.