I must have missed this thread first time around, so thanks for the bump, George!

I remember 5 star petrol but only just. We use to call in at a friend of my father's, when travelling up to/back from Scotland, who ran a haulage firm (Andersons - don't know if they're still around now). His lorries all ran on 5 star and he would fill our tank up before we left. I don't remember if it had any impact, but given we had a Zephyr then a Marina at the time, I think it unlikely!

Having never used premium fuel in any car before I gave V-Power (diesel though) a go in the Yeti earlier in the year. I don't fill up until after the light goes on (so around 8-9 litres left in the tank), and stop at the first click. There was a definite improvement in responsiveness (even after just 10 miles or so) and the maxidot gave a higher mpg rating (by 3 or 4) than on the previous few tankfuls by the time it was empty again, but the calculated figure was only up by 1mpg (at most). It had another tankful of V-power then, but didn't feel as responsive this time. There was no change when going back to the regular fuel save stuff.

I tried another tankful of V-power (Nitro by now) on the last fill up but one, and that felt no better than the regular diesel. I filled up with fuel save at the beginning of the week and it's already feeling very nippy again! I can understand the dilution effect, but if >90% of the fuel is V-Power it should lift the cetane (in my case) rating up enough to make some difference.

From my (albeit limited) tests, it hasn't been consistent enough, or given a significant increase in mpg, to warrant the 8p/litre extra it costs.

I put in V Power Nitro+ into my wife's 520d following Wynn's injector cleaner treatment few days ago. I drove the car for a day and I "think" I noticed it was running smoother but no stronger. MInd you, changing from vRS it was bound to feel sluggish

I wonder if a TMC'd 1.4 TSI will see benefit from a dose of Millers Petrol additive into a tank of momentum99, apparently a dose will add 2 RON to the base fuel....

Edited 16 October, 201312 yr by Wibb

'4 Octane'.  £20.00 worth still not enough for a full tank of fuel.

http://www.opieoils.co.uk/p-60237-millers-oils-cvl-turbo-octane-booster.aspx

 

I would seriously suggest not adding additives to the Super Unleaded..

& put nothing into a Twinchargers tank other than the fuel from the filling station pump.

Guys I know running turbocharged engines in motorsport will have the engine mapped (aftermarket ECU) on 98/VPower, so optimal for 98/99 - then run with Millers for a 2 RON "safety net".  Just in case the fuel on the day isn't absolutely fresh, to allow for slightly "off" atmospheric conditions etc.  They don't necessarily get any more power, but reduce the risk of melting the engine..

George,my memory is that a fair few 60's cars were designed to run on the old 5 star ( the Esso version was called "Esso Golden" IIRC)

The Rover 2000 TC was ,as mentioned,one but a more notable example was the first Jag "E" types,with 9:1 compression ratio.It just shows how engine design has advanced since cars can run a lot higher ratios now on lower octane fuel.

Fuels have changed quite a lot over the years.I recall in the late 80's I had an Opel Manta which ran OK on 4 star leaded...until at about that time they reduced the octane from 98 to 97 and then it pinked calling for the ignition to be retarded.

At about the same time a Reliant SS1 1600 was OK on top brand fuel but terrible on Supermarket stuff,so such controversies are not new....however in those days cars did not have the sophisticated engine management systems they now have.

Edited 17 October, 201312 yr by XK140