Regular Unleaded in the RT

[JayW]

I try to use Shell Premium in my RT, and it has always worked well. With the rising fuel prices I decided to try a tank of "regular", ie 87 octane. According to the manual this is not recommended, but I know many use it anyway.

 

The engine seemed to do fine in normal riding, but I did notice some transient knock on 3 or 4 occasions, especially when rolling on the throttle quickly from lower rpms. This could easily be avoided but this is not something I even have to be mindful of with the 93 octane fuel.

 

My conclusion - I'll go back to the (more) expensive stuff, but would not have a problem using lower octane gas in a pinch.

 

Any differing opinions?

 

Jay

[KDeline]

Humbug! I use the cheapest stuff I can find, and I have owned 3, 120,000 plus mile BMW's (my milage) with NO problems or damage. If it knocks, downshift and hammer it.

[Ken H.]

Any differing opinions?

Yup!

 

I've always used the cheapest fuel I can find. No issues ever. That's why these bikes have a knock sensor after all.

[dyvking]

I try to use Shell Premium in my RT, and it has always worked well. With the rising fuel prices I decided to try a tank of "regular", ie 87 octane. According to the manual this is not recommended, but I know many use it anyway.

 

The engine seemed to do fine in normal riding, but I did notice some transient knock on 3 or 4 occasions, especially when rolling on the throttle quickly from lower rpms. This could easily be avoided but this is not something I even have to be mindful of with the 93 octane fuel.

 

My conclusion - I'll go back to the (more) expensive stuff, but would not have a problem using lower octane gas in a pinch.

 

Any differing opinions?

 

Jay

I have no issues with knocking in either my GS or RT, but noticed slightly lower gas mileage with 87. I conducted 'personal research' and found that using 87 octane as opposed to 91 saved me all of $0.50 per tank on average, with reduced power. I concluded that for the 50 cents, I'll take the extra power.

[JayW]

The knock sensor does not seem to be preventing knock, or am I hearing something else? I think that in fact the engine is knocking, which the sensor picks up on and then adjusts the timing accordingly to stop it.

 

I suspect the brief knocking I hear is not doing any serious damage, but I still would rather it not be there at all. Premium fuel seems to prevent it completely, which is why I will preferentially use it in my expensive engine. The fact that BMW also recommends premium is also noteworthy.

 

Jay

[LuckyLeif]

I have no issues with knocking in either my GS or RT, but noticed slightly lower gas mileage with 87. I conducted 'personal research' and found that using 87 octane as opposed to 91 saved me all of $0.50 per tank on average, with reduced power. I concluded that for the 50 cents, I'll take the extra power.

Yeah, but you're forgetting that all those quarters add up over a year of riding. Do the math ... if you ride 10,000 miles in a year, then in using premium, you would be spending an extra .... $17 a year, which is equivalent to one free tank of gas a year. Or, in ten years, that adds up enough to buy a tire. Oh, never mind, I'm with you on this

[Paul Mihalka]

Yeah, but you're forgetting that all those quarters add up over a year of riding. Do the math ... if you ride 10,000 miles in a year, then in using premium, you would be spending an extra .... $17 a year, which is equivalent to one free tank of gas a year. Or, in ten years, that adds up enough to buy a tire. Oh, never mind, I'm with you on this

In rounded numbers 40.000 miles/year @ 40mpg @ $.20 difference between 87 and 91 is $200. That's four Motel6 nights!

[johnlt]

In rounded numbers 40.000 miles/year @ 40mpg @ $.20 difference between 87 and 91 is $200. That's four Motel6 nights!

 

or 2000 bottles of beer on dime night!!

[AdventurePoser]

On my last long ride I substituted mid grade fuel for the normal hig-test. No change in performance, but my mileage was down significantly with the use of the cheaper fuel.

 

Steve in So cal

[Deadboy]

My 04 pings big time with cheap stuff.......I'll stick with high test. I don't think the pre-1200's have knock sensors but I may be wrong.....

[Ken H.]

I don't think the pre-1200's have knock sensors

That's correct.

 

But then this is the hexhead forum!

[LuckyLeif]

In rounded numbers 40.000 miles/year @ 40mpg @ $.20 difference between 87 and 91 is $200. That's four Motel6 nights!

Touche! I never stopped to consider what motel costs would be for people who really rack up the miles. Now I understand why some high milers are generally seen camping.

[John in VA]

Maybe all gasoline brands actually hardly differ, but my bike and car have always thrived on Chevron premium with Techron. At my neighborhood station it costs about 6% extra over regular. Riding a premium bike with 12:1 compression, adjusting riding technique to avoid pinging on cheap regular gas isn't worth the puny savings to me -- but then, I don't put on 40k miles a year. Where Chevron is unavailable, I go with Amoco/BP, Shell or ExxonMobil premium in that order. I'd probably push the bike rather than buy Citgo, but that's another story for another forum.

[Deadboy]

I don't think the pre-1200's have knock sensors

That's correct.

 

But then this is the hexhead forum!

 

True, but I seriously doubt KDeline has put that many miles on hexheads alone......

[xoomerite]

I find that my mileage is less with lower grades of gasoline. For instance, 93 octane costs 6.5% more than the mid-grade, but produces 10% more mileage. Knock compensation notwithstanding, I will stay with the 93 octane.

[Pictou]

In addition to the usual reasons cited for using premium I also use it for environmental reasons. Everything I read tells me that vehicles designed for premium fuel will get better gas mileage on premium. Better gas mileage equates to fewer emissions. It may be a small thing but it all adds up.

[JayW]

I think the average consumer wastes their money by buying Premium, especially if the engine in their vehicle is designed for 87 octane fuel. It is my understanding that the further refinement necessary to make premiuum actually nets fewer gallons of gasoline per barrel of oil, so I'm also not convinced that using Premium is better for the environment either. I am also not aware that using premium usually yields better mileage - in fact there is less energy available per gallon compared to regular unleaded. However, high compression engines can develop more power if they are designed to take advantage of the lower propensity for detonation with high octane fuels.

 

I use the expensive stuff in my RT (but not the family minivan) because the engine is made with it in mind, and I don't want to have to deal with knock.

 

Jay

[SANTA]

I'm surprised that the motorcity expert "mitch_lets use his real_name" hasn't chimed in, if i recall he did an excellant expose on gas-o-line a while ago.

 

here in sask, regular has 10% ethanol content, so that reduces the overall btu value of the gas and also affects the mileage, because mid grade is a 50/50 blend of regular and premium it has an est ethanol content of 5%.

 

i have found that in stop and go traffic, my bmw pings less on premium, but out on the open road there seems to be no difference so regular runs fine, other things affect it much more such as altittude... at "Un" 5, in the Gunnison elevations it felt like a slow pig...

[Paco]

I think there are other features of gasolines in addition to anti-knock properties that are important to the health of our internal combustion gasoline engines, namely keeping deposits on valves, pistons, etc to a minimum.

 

To that end, a number of gasoline retailers have created performance standards called Top Tier to which they agree to comply. To date these Top Tier retailers include:

 

QuikTrip

Chevron

Conoco

Phillips

76

Shell

Entec Stations

MFA Oil Company

Kwik Trip/Kwik Star

The Somerset Refinery, Inc.

Chevron-Canada

Aloha Petroleum

Tri-Par Oil Company

Shell-Canada

Texaco

Petro-Canada

Sunoco-Canada

 

For more information on Top Tier gasoline standards see:

 

http://www.toptiergas.com/

[marcopolo]

I personally don't understand spending thousands on a BMW, and then not using the grade of gas recommended by the mnaufacturer -- unless one has no other choice on the road, which sometimes happens.

[Illini]

I put 93 Octane (Shell Vpower or Mobile) and get 43 miles per gallon and that's with the cruise set at 90 mph! If I put in cheap gas milage drops off to 30 mpg @ 90 mph! I can't drive 85!!!

 

But that's the beauty of living in the flat lands- I can see for miles and miles and miles!