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What's the opinion on super unleaded? Is it worth the extra cost? I understand it gives you extra MPG and cleans the engine. Is this true?

I had an e85 3.0 for 5 years, never used it, now in e89 and not using. I prefer to annually service my cars rather than wait for the mileage intervals. Use the saving of normal versus super to fund the additional service cost.

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.

I've just put a tank of BP Ultimate in, I consistently get 34 - 34.4mpg on my work run with normal unleaded, so I'll let you know if I see any difference in mpg with super.

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 always run V Power Nitro 99 in my 35is. Increased mpg, Additives better for the engine etc.....

Have a search on the forum for previous posts - You will find every answer under the sun!

I find I get enough extra miles out to warrant the cost. If it cleans better, then even better still.

AlfaScozzesi wrote: ↑Tue May 23, 2017 7:43 pm Again most think it takes a couple of tanks to get the full benifit as the engine management adjusts to the different octane rating.

Yeah when I disconnected my battery the car went back to a base fuel map, and it took about 200-300 miles before my mpg was back to normal.

I Never run on anything less than SUL

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.

Thanks for all your comments. I'll definitely try super unleaded for the foreseeable and see how it goes.

BMW say use 95 in the 35iS, so I do.

Busterboo wrote: ↑Tue May 23, 2017 9:46 pm 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! ...