Super Unleaded

[oldomega]

The other day I pulled into a petrol station to find they only had 97 octane (super unleaded) petrol. Instead of my usual 50 litres I put in 30 as it carries a hefty cost premium. However half a mile down the road the engine seemed to be running smoother. I have to fill up later today but the question is do I use super unleaded again or am I deceiving myself. Does anyone use super with a standard engine? My Callie is a V6.

[Mark1]

I use standard fuel on a modified engine.

[matty0785]

i run super in the skyline as thats what its mapped to run

normal unleaded = pop bang flames misfire

[GreyDJ]

Generally speaking you can get up to about 5% more power using higher RON fuel as the anti pre-detonation 'pinking' algorithm in the ECU is able to advance the ignition.

[Callyman]

Just use std fuel, you wont feel any power increase using a higher octane fuel.
If you had a tuned engine or turbo'd that's another thing.

[oldomega]

I filled up with standard unleaded yesterday. My Callie goes in for a service and MOT soon (fingers crossed for a smallish bill). I will try both standard and super, and maybe timing 40 - 60 mph and measuring mpg to see if there is any real difference.

[matty0785]

higher octane fuel burns faster and slightly hotter on a non tuned or non turbo car its not worth the extra cash as it will do slightly less mpg and return no power gain unless your engine is turbo'd or tuned to run higher octane

[Stupink]

It depends on driving style imo, as above if you drive HARD, then the ecu will *retard the ignition less especially hot days.
if you're just driving about pootle pootle low revs, the ecu is going to be running pretty much the same timing anyway so you'll see no difference.

if you're minted just use high octaine, if you're not, use normal fuel unless turbo'ed, or you'll find as above the extra costs will soon start to depress you.

[matty0785]

the extra cost of the super unleaded does get to you after a while as im considering having the skyline mapped to run normal octane fuel due to being my daily driver now