R1200xx and regular unleaded.

[steve.foote]

I've read quite a bit of discussion regarding running premium vs. regular unleaded in the new Hexheads. Personally, I've always run premium in my 1150RT and 1200GS, but this weekend wanted to try regular to see the difference.

 

So far, no noticeable difference. Same power, no pinging, and no side effects. Other than saving a buck-something at the pump, it seems to perform the same. The only thing I haven't been able to compare is mileage.

[wilsons]

I've often wondered that myself, in the the bike I guess I wont care, in the truck, however, I totaly care, thats like 8bux

[jakfrost]

That (mileage...) is the ONLY place I have seen a difference. And I'm still not sure if I can believe the results. Just too dramatic, I need to do further investigation to confirm the initial results.

So far it would seem that I am getting about 10 to 12% better mileage better with 93/94 vs 87.

 

That comes from the onboard computer, I want to confirm with actual mileage and fuel at fill up...

 

Jim

[ShovelStrokeEd]

Steve,

Wouldn't surprise me if the milage didn't improve slightly. There are a few more BTU/gal in the regular stuff.

 

I have all but given up on attempts to get my Blackbird to give me reasonable fuel consumption. Mind you, its not that horrible just not up to what I am used to from years of riding BMWs. Riding on freeways at my normal 83mph GPS, I get between 34 and 36 mpg depending on wind and luggage configuration. Recent trip across Florida to Tampa and back got me 38 mpg but speeds were constrained by the roads I was on and I seldom saw much above 70 mph (only hit triple digits once while passing a line of trucks). My moving average speed was down to about 60 mph on the 500 mile round trip as opposed to my more normal 74 or so.

 

Of course, the BB is a 4 cylinder and, with its smaller chamber and piston surface area even at 11:1 compression, it runs happily on 87 octane regular.

[Paul Mihalka]

All the R1200 bikes have knock sensors on the engine. That means that if you use regular gas and the sensors feel incipient knocking, the engine control reduces slightly the ignition advance. While that is happening you have a slight loss of performance and mileage. On a good engine this might only happen at something like full throttle at relatively low rpm, like full on at around 3000 or 4000 rpm. I personally would use regular unless I go on a track day.

[KiwiAdventure]

Good luck with your warranty. I don't understand why you would use a low grade fuel. It saves you stuff all money. The price of gas in the states is cheap.

Why would the manual and instruction on the gas tank say use high octane gas.

Why buy a BMW when all you want to do is feed it cheap gas.

[duckbubbles]

I haven't tried it on my ST, but my K-bike gets enough extra mileage out of premium to justify the cost difference. My biggest peeve is the pumps with only one nozzle for all grades. You get almost a gallon of whatever the last guy put in before you start getting what you are paying for. Seems like there ought to be a class action of some type against that.

[KiwiAdventure]

I haven't tried it on my ST, but my K-bike gets enough extra mileage out of premium to justify the cost difference. My biggest peeve is the pumps with only one nozzle for all grades. You get almost a gallon of whatever the last guy put in before you start getting what you are paying for. Seems like there ought to be a class action of some type against that.

 

Have you got details of this

[David]

Steve, we've burned 87 every time we've gone to Mexico. That's all that's available in the little towns.

 

Mileage: no idea what we got.

 

Knocking: none.

 

Surging: quite a bit, at light throttle openings crawling along in first gear with a hot engine. Nothing terrible, but you can tell the difference.

 

I'm really pleased with how this thing isn't at all fussy about the fuel you put in it.

[smiller]

Why buy a BMW when all you want to do is feed it cheap gas.

87 octane gas is not 'cheap', just a lower octane. If an engine doesn't ping at a given octane rating then a higher octane fuel is in no way superior and using it does nothing more for you than waste your money.

 

That is... if the engine doesn't ping... but if it does ping and the knock sensor is retarding the ignition timing a significant amount of the time then that would explain why one would see better mileage with a higher octane fuel (and that is the only reason.) But I agree with Paul... normally you shouldn't be triggering the knock sensor that much unless you are really loading the engine.

[KiwiAdventure]

normally you shouldn't be triggering the knock sensor that much unless you are really loading the engine.

 

[KiwiAdventure]

Steve, we've burned 87 every time we've gone to Mexico. That's all that's available in the little towns.

 

Mileage: no idea what we got.

 

Knocking: none.

 

Surging: quite a bit, at light throttle openings crawling along in first gear with a hot engine. Nothing terrible, but you can tell the difference.

 

I'm really pleased with how this thing isn't at all fussy about the fuel you put in it.

 

That is what the knock sensor is for. When their is only low octane gas available.

[kdude]

I'm riding an 05 GS and after a good break in I tried to go regular. I noticed a power drop in the higher rpm range. Gas mileage came down and did not have any knocking.

 

The bike runs better with the good stuff.

[steve.foote]

The reason I posted this is that there seems to be a lot of confusion and misinformation about octane. Here is what Chevron has to say on the subject:

 

Q. What is octane?

A. Octane is a measure of a gasoline's ability to resist knock or pinging noise from an engine. In older vehicles, knock may be accompanied by engine run-on, or dieseling. Knock is the sharp, metallic-sounding engine noise that results from uncontrolled combustion. Severe knocking over an extended time may damage pistons and other engine parts. If you can hear knocking, you should have your engine checked to make sure it is calibrated correctly and does not have a mechanical or electrical problem, or use a higher octane gasoline.

 

In most vehicles no benefit is gained from using gasoline that has a higher octane number than is needed to prevent knock. However, in some vehicles equipped with a knock sensor (an electronic device installed in many modern engines that allows the engine management system to detect and reduce knock), a higher octane gasoline may improve performance slightly.

 

Q. Which octane grade should I use in my car?

A. Use the recommendation in your car owner's manual as a starting point for selecting the proper gasoline. If you notice engine knock over an extended time and your engine is adjusted correctly, try a higher octane gasoline. Also, higher octane may provide a performance benefit (better acceleration) in cars equipped with knock sensors. Many late model and high-performance (turbo-charged and supercharged) cars fall into this category.

 

And here is another from cars.com:

 

If your car requires high-octane gasoline and you habitually use regular gas because the engine exhibits no sign of knock, you’re outsmarting yourself. Most modern, computer-controlled engines include a knock sensor that detects knock and retards the ignition timing, causing the spark plugs to fire slightly later in the cycle. This typically prevents abnormal combustion and knock, which allows vehicles specified for premium fuel to run on lower-grade gasoline if it is all that’s available. While this removes the immediate hazard, it’s a bad idea to make a habit of running a vehicle on gasoline of lower-than-recommended octane. Retarding the spark causes a richer fuel/air mixture, which decreases fuel economy, increases emissions, causes the engine to run hotter, and reduces the longevity of both the engine itself and the catalytic converter. The money you save by pumping low-grade fuel into a car that demands higher octane is lost anyway, in decreased fuel economy and possibly gradual damage.

 

The State of Minnesota weighs in.

 

The American Petroleum Institute:

 

Most cars give optimum performance on regular or mid-grade gasoline. If you're buying premium and your car's not running any better than it does with a lower-octane gasoline, you're probably wasting money. However, some cars may operate better on premium because of additives. Additives, which are found in all gasolines, keep engines clean and make them run more efficiently. Some brands have more effective additives and some use bigger doses in their premium grades.

 

Hense the confusion.

[ShovelStrokeEd]

snip In most vehicles no benefit is gained from using gasoline that has a higher octane number than is needed to prevent knock. However, in some vehicles equipped with a knock sensor (an electronic device installed in many modern engines that allows the engine management system to detect and reduce knock), a higher octane gasoline may improve performance slightly.

 

That is probably the most sensible thing in the deal. Your 1200 has knock sensors and it will allow you to run a lower octane rated gas without danger of damage to the motor. This may come with a small performance penalty in both power output and fuel consumption.

 

Mixed in with all the hoopla is the fact that your engine is quite a bit different from a normal automotive engine. The large bore and combustion chamber area as well as the relatively high compression ratio make it a bit less tolerant of low octane rated fuels. My 1100S has about the same power output as your GS, albeit, slightly higher specific output due to less displacement. It will tolerate 89 octane stuff so long as I am not accelerating hard from low RPM but it really prefers the 91. The BB, with similar displacement and 50% more output runs fine on 87. Smaller bore, smaller chambers, about the same compression ratio but, I suspect very different cam timing which greatly effects cylinder pressures at lower RPMs. It's fuel mapping is also considerably richer than that programmed in the BMW as witness the poor fuel consumption performance. It's all a trade off.

 

If you are so inclined, you could always roll your static ignition timing back a bit. You might, at first, notice a small performance drop but ride the thing for 500 miles and it will feel normal again.

[steveknapp]

Your 1200 has knock sensors and it will allow you to run a lower octane rated gas without danger of damage to the motor.

 

In a past life I worked on one of the top shelf production (read cheap enough to really use) knock detection strategies.

 

Things I learned:

 

- The systems aren't perfect. But they are pretty good.

- It's challenging to have the same strategy detect both "US style" knock, high load, WOT, low RPM and "european style" high load, high RPM.

- They react to knock, and the idea is they can react quickly enough to avoid damage. They are also constantly trying to advance the timing curve to find the edge.

- Your ears make crappy knock sensors. The knock signature blends in really nicely with engine noise. If you can hear it, it's bad and any knock sensor worth paying for should have detected it long ago.

[smiller]

That's some interesting information Steve.

 

They are also constantly trying to advance the timing curve to find the edge.

 

If that's the case (vs. merely retarding the spark if knock occurs) then I could see why there might be a mileage improvement with higher-octane fuel.

[duckbubbles]

Kiwiadventure- check your personal messages for one from duckbubbles.

[ShovelStrokeEd]

Agreed on all points, in particular the ears part.

 

I have had a good deal of experience with detonation and its effects having run both Nitrous Oxide and Nitromethane fueled motorcycles at the drags. The effects can be devestating under high load conditions. Ring lands collapsed, broken pistons and even crankshafts, holes blown in the roof of combustion chambers, spark plug ground and, for that matter, center electrodes completely gone. Of course, these are under extreme conditions with just insane compression ratios and primitive fuel control systems.

 

Doubtful you would see this kind of stuff on a street driven motorcycle although my Guzzi is all but unrideable in hot weather on even the local 91 Octane. Hemi chambers have really poor anti-knock characteristics. Gotta get around to changing to much thicker head gaskets one day.

 

There is also a distinction between pinging, think BB's in a tin can and true knock, which sounds more like rocks in a big garbage can. The former, while not desireable, will do little more than kill efficiency and can be mitigated to some extent by judicious use of the throttle and the tachometer. The latter is to be avoided at all costs. It takes very little time under detonation to do serious damage to a motor.

[steve.foote]

Nice responses so far. That's the kind of info I've been waiting for.

 

Here's how my opinion is being shaped at this point:

 

1. Dollars-smallars. The price difference between regular and premium is meaningless. I started this experiment because I was interested in the possible benefits of regular (quicker burning) vs premium. Since the R1200 engine has knock sensors, it makes sense that it could deal with lower octane fuel.

 

2. My BMW manual does specify RON 95 which works out to 91 octane at US pumps. I generally go with the manual unless I have a compelling reason not to.

 

3. Here in Georgia, we have 87, 89 and 93 octane grades available. Many places around the world only supply 87, and there is no expectation not to run these motors there.

 

4. Steve makes a good point about our ears being lousy knock sensors. In the 21st century, the seats of our pants aren't sensitive enough any more.

[IanW]

I have an Australian spec 05 R1200RT the manual states:

The engine is designed to run on Super Plus (Premium) unleaded (98 RON). Use fuel of this grade by preference, in order to achieve rated performance and fuel consumption.

 

You can also run the engine on fuel of the following grade:

Super Unleaded (95 RON, 85 MON)

 

Ian

[steveknapp]

Super Unleaded (95 RON, 85 MON)

 

So 90 via the US R+M/2 method, which is still higher than our 87 "regular".

[Jim VonBaden]

I have run only regular gas, except a couple times as experiments, and haven't noticed an appreciable difference. My mileage is consistant 43mpg mixed, and as high as 50 mpg on the freeway taking it easy.

 

I don't see the need for premium on my 12GS.

 

Jim

[Pictou]

A British mag dynoed a new K1200S with regular and with premium fuel. The bike made 8hp less on regular fuel. Since the motors are very different I don't know if this is at all relevant to this discussion.

[Paul Mihalka]

A British mag dynoed a new K1200S with regular and with premium fuel. The bike made 8hp less on regular fuel. Since the motors are very different I don't know if this is at all relevant to this discussion.

With any motor equipped with a knock sensor but designed for high octane fuel to get maximum performance, with low octane fuel the knock sensor will reduce spark advance (or open the waste gate on some turbos) which reduces top performance. 8 hp loss? "Only" 159 instead of 167? I could live with that

[JayW]

Why does the manual not "allow" for the use of 87 octane fuel if the knock sensor would protect the engine at an octane this low? "Regular" seems to work OK based on the posts here, but I have always used premium in my bike, and would hesitate to use below mid-grade because of what the manual says.

 

Jay

[Pickaxe]

I have run only regular gas, except a couple times as experiments, and haven't noticed an appreciable difference. My mileage is consistant 43mpg mixed, and as high as 50 mpg on the freeway taking it easy.

 

I don't see the need for premium on my 12GS.

 

Jim

You're right, the GS isn't designed to perform any better on the higher octane fuel. However, the RT is and does produce more power with the premium.

[steve.foote]

You're right, the GS isn't designed to perform any better on the higher octane fuel. However, the RT is and does produce more power with the premium.

 

Unless your comment was meant to be tongue-in-cheek, where did you hear that?

[KiwiAdventure]

I have run only regular gas, except a couple times as experiments, and haven't noticed an appreciable difference. My mileage is consistant 43mpg mixed, and as high as 50 mpg on the freeway taking it easy.

 

I don't see the need for premium on my 12GS.

 

Jim

You're right, the GS isn't designed to perform any better on the higher octane fuel. However, the RT is and does produce more power with the premium.

 

You guys make me laugh

[Pickaxe]

You're right, the GS isn't designed to perform any better on the higher octane fuel. However, the RT is and does produce more power with the premium.

 

Unless your comment was meant to be tongue-in-cheek, where did you hear that?

It wasn't tounge in cheek, it's a fact. The RT is in a higher state of tune, with a higher compression ratio and develops more power with the higher octane fuel.

The GS is designed to run on regular fuel and if need be, will even run on the very low grades only available in some countries.

It's all in the owners manual.

[Richard G]

I am glad this topic came up.

 

It has prompted me to try the premium fuel in my R12RT.

I have only been using regular fuel.

With the regular fuel, I thought my bike was running fine,and it was for the most part.

But now and then if I happened to let out the clutch a bit too quick and didnt give enough throttle, the revs would drop down to stall speed.

At that time I would hear a few loud knocks from the engine.

I knew that didnt sound good. Besides that, there was no problem riding the bike. I also figured part of it was the taller first gear.

 

But the discussions of the knock sensor retarding the timing

and lowering power and mileage, got me thinking.

So last fillup I put in premium to see if I would notice any differences.

 

I did notice it was much easier moving the bike off from a stop in first gear.

I didnt need as much throttle as before and could take off at very low revs without the feeling of the engine bogging.

 

It was mentioned previously on this thread that you could take off at 1500 rpm's. Even on a hill! I was thinking

"not with my bike you cant". Well, the change in fuel grade definitely made the difference.

 

Throttle response is better too. Just a little twist and it just pulls.

Not that it wasnt a fast bike before, just more responsive.

 

And the engine seems to be smoother through the whole rpm range.

 

I wouldnt have thought it makes that much difference, but on my bike it did. Your results may vary.

 

It looks like mine will be getting steady premium from now on. Price permitting.

 

Rich

[Jim VonBaden]

I took an 1100 mile ride this weekend, and I tried several tanks of premium in the middle of the trip, regular before and after. I noticed about 2mpg difference, though that is hard to verify on a small sample, but no real improvement in any other way.

 

My riding was mostly 75-80 mph freeway, we rode up to NH from DC to buy a new R1200ST. Two-up on the way there, and alone on the way back, and no noticable difference in fuel mileage that way either.

 

Jim

[wilsons]

I bring this back up cuz my dad and I were talking about gas tonight. He was at a local bike shop in Erie, and a guy came in and asked for gas as he was having trouble. It ended up in a discussion about octanes, and short story shorter, if you use 93, you risk getting old gas due to prices and people not wanting to pay for 93, so it sits, and becomes old.

 

So far, I haven't had any issues with this, but apprently a few people north of me have.

 

Also if I run 87, everyone seems to think it'll be ok except if I'm hard on the engine. yay or nay? This seems kinda touchy..

 

Thoughts?

 

Thanks

[JohnBeaven]

I have an Australian spec 05 R1200RT the manual states:

The engine is designed to run on Super Plus (Premium) unleaded (98 RON). Use fuel of this grade by preference, in order to achieve rated performance and fuel consumption.

 

You can also run the engine on fuel of the following grade:

Super Unleaded (95 RON, 85 MON)

 

With the price difference of 3c/litre between 95RON and 98RON or about 75c per tank I can't see the point of not using the 98RON unless supply is an issue. Also, given the recommendation in the Owner's manual I wouldn't even attempt to use 92RON even though it is 9c/litre cheaper than 98RON.

[timmr]

Interesting point about the higher priced gas getting stale in the ground, I've wondered about that too. I frequent a Shell station where I've noticed alot of higher end cars filling up. That's where I fill up the K bike. The manual requires high test and that's what it gets.

My GS has a sticker right by the gas cap that says 89 octane minimum. I don't figure many people use the mid grade stuff so I usually just fill it w/ premium. Once summer is over and the heat subsides, I may try some regular. On the other hand the bike is running fine as is, why mess with it?

I did notice that the RT's have a claimed compression ratio of 12:1, the GS is stated at 11:1, and the KS is 13:1.

It's nice that the GS can use regular if needed. In some out of the way places that's all there is.

[timmr]

Another thought and a question.

On all the oil threads it's generally advised to use the recommended grade/viscosity and stick to BMW'S recommended change intervals. Why are we willing to advocate using a lower than recommended grade of gas? Given, there are those times when the lower grade is all that's available, but I think it's the exception rather than the rule. Any thoughts?

[Pictou]

The only reason to run lower grade fuel (other than the argument it might be getting stale these days) is for cost. BMW claims the fuel economy will be diminished with lower grade fuel which, if ture, would eat up some of these savings.

 

For me I see no reason to make a compromise when it comes to my motorcycle. It was designed for premium fuel and that's what it'll get. In Canada the difference if fuel costs is 10 cents a litre. That is only $2.70 on a full tank of fuel. I spend more on coffee in a day than that. I like the fact that the bike can use lower graded fuel in a pinch but it for the trivial difference in price it will never be my choice.

 

 

Another thought and a question.

On all the oil threads it's generally advised to use the recommended grade/viscosity and stick to BMW'S recommended change intervals. Why are we willing to advocate using a lower than recommended grade of gas? Given, there are those times when the lower grade is all that's available, but I think it's the exception rather than the rule. Any thoughts?

[wilsons]

Price doesn't so much scare me, I'd save anywhere from $6 to $16 dollars a month depending on how much I ride. Oh God! I can't afford that!!

 

Seriously though, I am mildly concerned about getting stale/bad gas thats not going to be used as much. Again, I haven't ran into issues. YET. I just don't know the chance's of it really happening.

[ben1364]

I agree with you. I think! <g> Retailer inventories are usually managed to reflect sales volume and to coincide with delivery schedules as closely as can be projected. Hence the likelihood of finding "stale" gasoline anywhere but a very remote mom and pop store is very rare, IMO.

[wilsons]

Not in Edinboro PA. (possibly Mckean PA). Not sure where the problem was but its a true case indeed. I guess in Cinci I don't have to worry. And being that my bike see's 6grand+ quite often I better stick with 93+