Unleaded vs Super Unleaded petrol.

Amanita_2

My Mk3 (NC) MX-5 is run pretty much exclusively on Shell V Power - occasionally in Shell free areas it gets BP Ultimate.

I get a few extra MPG out of it but mainly there is a noticeable improvement in the throttle response. So much so that when forced into an emergency fill up of Tesco super unleaded I wondered what was wrong with my car.

thescouselander

I tried Super Unleaded in my BMW 330 Ci - there was no difference at all in fuel economy and the acceleration was no diifferent either.

negg

I was once told it can improve economy and performance on cars with turbos or superchargers.

I tried in in my Merc (supercharged), but no difference in performance or economy. Either that or the difference was so small, I didn't notice. My car isn't a high power version and I understand that Impreza's and Evo's can benefit from the 98 RON.

tomstickland

I used to run a 1991 BMW 318iS and noticed no difference at all between various petrol brands. I didn't really bother looking too hard though.

Rallydriver

Depends on the model of Impreza - UK, modified, import etc. All cars sold in Europe from a certain date (1998?) are required to be able to run safely on 95RON fuel. Only a few cars will notice any difference at all, even if they have knock sensors. Stuff like Imprezas and Evos it will make a difference to (Jap imports must run V-power, Tesco 99 or a super 97RON with an octane booster.) Expensive things like Ferraris, etc. will benefit from it too. UK Imprezas, a standard UK turbo 2000 awd would be safe on 95RON as would a UK WRX for normal driving. A UK STi or any modified UK impreza should run 97RON minimum and imports should be 99RON.