Super Unleaded
- Thread starter AndyO
- Start date
I always have in my "loved" car, not so much in any runabout.
The thought process being that the expensive additives will keep the engine better than fuel without. There are some who say better fuel economy levels the extra cost and although better I don't think it quite does this.
Not the way I drive anyway
Lots of threads and opinions on this.
The thought process being that the expensive additives will keep the engine better than fuel without. There are some who say better fuel economy levels the extra cost and although better I don't think it quite does this.
Not the way I drive anyway
Lots of threads and opinions on this.
Again most think it takes a couple of tanks to get the full benifit as the engine management adjusts to the different octane rating.
I find I get enough extra miles out to warrant the cost. If it cleans better, then even better still.
Super for me. In my mind it makes my car faster 
So on N54 cars at least they're mapped to utilise the better detonation characteristics of high Ron values and timing (therefore power) is reduced a little on 95ron.
I can confirm this on a dyno day where identical cars with different Ron fuel produced different power values. Difference was minor however at around 15hp.
I can confirm this on a dyno day where identical cars with different Ron fuel produced different power values. Difference was minor however at around 15hp.
Busterboo said:BMW say use 95 in the 35iS, so I do.
As you say ... the thing is designed to run on 95 so why use anything different? Extra mileage and faster acceleration may well be partly psychological after paying the extra! ...
Doesn't the lower octane stuff contain relatively more ethanol (?) than the higher octane stuff? And ethanol burns at a higher temperature?
I know that even in my little 850 Mini I now need to run the higher octane fuel just to avoid severe detonation when the engine is under load (most of the time). The same is true of the Alfa we have.
It just seems natural to run the higher octane fuel in the other 2 modern cars. It's only a small extra cost per tank and amounts to less than £200 per year.
I know that even in my little 850 Mini I now need to run the higher octane fuel just to avoid severe detonation when the engine is under load (most of the time). The same is true of the Alfa we have.
It just seems natural to run the higher octane fuel in the other 2 modern cars. It's only a small extra cost per tank and amounts to less than £200 per year.
Hmm this old chestnut again...
With my home Mapped turbo cars I use SUL, without a doubt. Purely from the 'insuring against pre det' argument.
With the Zed, I have owned for about 6 months, until recently, every drop of juice I put in it was SUL. I recently filled with 95 Ron (accidentally) and strangely found my mileage slightly better (go figure). 99ron=32mpg avg , 95ron=36mpg avg. No noticeable determination in performance and my det detector certainly isn't pinging.
I'm going to try a few tankfuls of the cheaper stuff for the sake of, very unscientific, experimentation. If anyone is interested I'll let you know how it goes.
With my home Mapped turbo cars I use SUL, without a doubt. Purely from the 'insuring against pre det' argument.
With the Zed, I have owned for about 6 months, until recently, every drop of juice I put in it was SUL. I recently filled with 95 Ron (accidentally) and strangely found my mileage slightly better (go figure). 99ron=32mpg avg , 95ron=36mpg avg. No noticeable determination in performance and my det detector certainly isn't pinging.
I'm going to try a few tankfuls of the cheaper stuff for the sake of, very unscientific, experimentation. If anyone is interested I'll let you know how it goes.
lordgrover
Member
Doesn't it say recommended minimum is 95?Busterboo said:BMW say use 95 in the 35iS, so I do.
The higher the octane rating then the more the ECU can advance the ignition and the engine can run more efficiently. This is hardly noticeable in NA engines but can make a very noticeable difference in turbocharged engines. This does generally increase the performance of the car.
In theory this will increase mpg but only if all other things are equal e.g. speed and acceleration kept the same. In practice most enjoy the increased performance, particularly improved acceleration, so the improved mpg doesn't really come to pass.
Vendors claim better additives in their SUL re engine cleaning and whilst this is certainly true between premium and supermarket brands I'm not convinced that there is a substantial difference between regular and super for the same brand.
You pays your money and takes your choice.
In theory this will increase mpg but only if all other things are equal e.g. speed and acceleration kept the same. In practice most enjoy the increased performance, particularly improved acceleration, so the improved mpg doesn't really come to pass.
Vendors claim better additives in their SUL re engine cleaning and whilst this is certainly true between premium and supermarket brands I'm not convinced that there is a substantial difference between regular and super for the same brand.
You pays your money and takes your choice.
