www.boxertrix.com

My K has always felt perkier and had better MPG from these higher octane fuels. But I tend to only put it in when going on longer journeys.

Just watched this

http://www.youtube.com/watch?v=gQghB4asSnI

and was shocked by the results, especially for the impreza, jeepers over 10% more torque and 14hp just from a fuel change. Perhaps my "seat of the pants o meter" is more sensitive than I thought

The K, like many, will run on 95 but BMW recommend >98 for optimum performance. Are the R12S's the same? I don't imagine it makes any difference on the old R11S motors? I've not noticed so anyway.

Not sure it makes a noticeable difference on the R12S. I was using it for a week at the TT and riding it hard Maybe a bit smoother low down.

Answer = Yep!

My 12S ran much better (smoother and a little quicker to rev up) on super unleaded. It too was designed to run on super, like the K, but would accept standard 95 RON fuels.

I think in a normal bike it may be less noticeable, but BMWs change their ignition timing slightly on 95 RON fuels, and only run at "full performance" on super. that’s how I understand it anyway....

It makes a huge difference on my 12S, if I have to use 95 ron ( as usual in wales) I get a much harsher engine vibe and poor performance along with much reduced mpg, on 97/98 or tesco 99 it runs very sweet and my mpg is improved by around 30 miles per tankful.

Steve

Steve1200S wrote:Answer = Yep!

My 12S ran much better (smoother and a little quicker to rev up) on super unleaded. It too was designed to run on super, like the K, but would accept standard 95 RON fuels.

I think in a normal bike it may be less noticeable, but BMWs change their ignition timing slightly on 95 RON fuels, and only run at "full performance" on super. that’s how I understand it anyway....

yes that's my understanding.

Really shocked with the additional hp and torque 5th gear got in their test

I think an engine needs to have a knock sensor in order to take advantage of high octane.
Otherwise it’s a waste of money.
The 1100 doesn’t have it, but the 1200 does. Don’t know about the 1150.

//T

Tapio wrote:I think an engine needs to have a knock sensor in order to take advantage of high octane.
Otherwise it’s a waste of money.
The 1100 doesn’t have it, but the 1200 does. Don’t know about the 1150.

//T

I'm not 100% sure, but I would have thought it would have been the opposite. If an engine isn't tuned to take advantage of the higher octane fuel, using it will be of no benefit. With a knock sensor fitted the EMU can back off the ignition advance to prevent pre-ignition when lower octane fuel is used.

My 11S made no difference with higher octane stuff.

I've been advised by the previous owner of the K100 I've just bought to use the higher octane stuff in that as there is less ethanol than normal petrol and the ethanol knackers all the seals.

The 1200 is designed / tuned to use 98 RON, at least if you want optimum performance. It has a knock sensor to retard the ignition when using low octane fuel.

Personally, I can't feel any difference so typically use 95. On occasion I bung a tank of the good stuff in expecting to feel some change, but never do.

In cooler weather my GSA shows no difference.

However anything above 20c and regular 95 octane it runs like a pig

My 11s does approx. 20 more miles per tank on '98. Can only get it across the border though..

SAS Tom wrote:My 11S made no difference with higher octane stuff.

I've been advised by the previous owner of the K100 I've just bought to use the higher octane stuff in that as there is less ethanol than normal petrol and the ethanol knackers all the seals.

depending on the age of the K100 you may need leaded, I seem to recall that most of the 8 valves didn't have the hardened valve seats required, oddly enough the airheads from the era did so I'm puzzled why BMW didn't equip the K's thus?

My 11 runs better on 98 for long runs this is what i use it's noticeably smoother and sweeter

I was wondering about this, so tried a tank of 98, and had worse mpg.... I think I'll try it again though and try to compare with similar riding conditions, after this discussion...

I filled up my GS a few weeks ago, in France - on 98RON, and the consumption improved approx 8%.

In some situations (where you are putting a lot of miles in a day) it can make the difference between filling up once, or filling up twice - that can make a significant difference if you are on a schedule.

The engine seemed to pick-up easier too.

Al