99 Octane Fuel - Noticeable benefit!

[r11co]

My E90 330i is the first car I have (knowingly) owned that makes it known it can work with a range of octane ratings - the sticker on the fuel flap gives a range from 91-100 and AFAIK the performance figures in the handbook are quoted for 98 octane. I've always been the first to tell people not to waste money on 'superfuels' unless they know they can benefit (knock sensors, variable timing etc.)

Anyhoo, a Tesco has opened near me recently, and having racked up a decent 5p off a litre I though I would fill up with their Momentum using the discount to offset the cost over the 95 stuff I usually use.

Well, I didn't want to report back until I'd run a few tanks through to make sure it was no fluke, but I have now seen an average increase of 45 miles from a full tank since I changed to using the stuff. That is the equivalent of 2 extra gallons' mileage over what I was getting before!!

There'll be some saying 'cool story bro', but I am genuinely surprised at the amount of the improvement. Most of my journeys are not exactly mpg friendly (rush-hour commute).

There was another thread recently where someone expressed disappointment at the actual mpg they were getting on their 330i compared to quoted figures. Well, I guess there is the answer!

[StuntmanMike]

My E46 330 was ran on 99 for years, for some reason I switched to normal unleaded, tbh I think it was the lack of availability in my area, never noticed a jot of difference in mpg or performance.

[Poopipe]

My 172 could run on either. Apart from noticeably increasing its willingness to go fast, super gave me enough extra mpg to cancel out the extra cost.

Since then all my cars have been specifically mapped on 99 - if you get caught short and have to use 95 or 97 to get home you really know about it.

Its not snake oil and if your car is intended to be run on super then in all likelyhood you will see benefits from doing so.

Eta:
That said , if its capable of adapting to 95 you arent going to do any harm by using it.

Edited by Poopipe on Saturday 13th September 10:18

[007 VXR]

Have always used 99 in mine, but its not standard and mapped to run on it.
I will only used Shell Nitro or if i have to Tescos.

[xxChrisxx]

You will see an improvement, its just not quite as much as you think it is. Even minor reductions in stationary/slow traffic can have huge effects on economy.

A few tankfuls indicates a couple of months, ie July and August.

I'd run it a couple more months before drawing conclusions on numbers. If mine was anything to go buy the difference was about 5%.

[TheAllSeeingPie]

I had to fill up on regular last night and noticed a mildly grumpy engine. Best thing to do is floor it a few times it let it calibrate the knock sensors and it'll do its best it can for the fuel. I definitely get 1-2mpg more on super/99 but when you're only doing 21-24mpg and 450 miles a week it's not something to obsess about really.

[wemorgan]

r11co said:

Well, I didn't want to report back until I'd run a few tanks through to make sure it was no fluke, but I have now seen an average increase of 45 miles from a full tank since I changed to using the stuff. That is the equivalent of 2 extra gallons' mileage over what I was getting before!!

What's that as a % increase? ~15%? Sounds unlikely to me, but it's your car, your data. 99 RON is only 2-4 RON higher than the bog standard stuff and I doubt it's a linear increase of mpg vs RON. But if it works for you, keep going.

[MJK 24]

If you're ever on the continent, try Agip 101 or Shell Racing 100. The Agip is amazing stuff.

[r11co]

StuntmanMike said:

My E46 330 was ran on 99 for years, for some reason I switched to normal unleaded, tbh I think it was the lack of availability in my area, never noticed a jot of difference in mpg or performance.

The N52B30 engine on the e90 is a fair bit more 'techie' than the e46 330i engine. Not really comparing apples with apples there!

wemorgan said:

What's that as a % increase? ~15%? Sounds unlikely to me, but it's your car, your data. 99 RON is only 2-4 RON higher than the bog standard stuff and I doubt it's a linear increase of mpg vs RON. But if it works for you, keep going.

I've got to admit the improvement noticed so far seems a bit 'optimistic'. I'll keep a watching eye on it..