On another Ducati site, I was whining about my gas mileage and someone recommended using 87 (gasp) octane fuel.

I have a 2006 ST3, and the manual is alarmingly clear: 93 octane (Premium) only.

What's the compression ratio on your scooter?  What octane do you use?  How long?  Any octane-related problems?

Thanks.

George

Quote from: GeorgeInDallas on October 24, 2008, 07:53:43 PM
On another Ducati site, I was whining about my gas mileage and someone recommended using 87 (gasp) octane fuel.

I have a 2006 ST3, and the manual is alarmingly clear: 103 octane only.

That cannot be right. 93 is the highest you can get at typical gas pump. Any higher, and you are using race fuel (about $15-20/gallon nowadays). In California, the highest they even have is 91 Octane.

Quote from: cm on October 24, 2008, 08:27:53 PM
That cannot be right. 93 is the highest you can get at typical gas pump. Any higher, and you are using race fuel (about $15-20/gallon nowadays). In California, the highest they even have is 91 Octane.

I beg your pardon, you are correct.  I use 93 octane - I think the manual calls for some higher number, but that, I am told, is a Euro octane number.  I will correct my original post, if possible.

I'm still curious as to what others use.

Quote from: GeorgeInDallas on October 24, 2008, 07:53:43 PM
On another Ducati site, I was whining about my gas mileage and someone recommended using 87 (gasp) octane fuel.

I have a 2006 ST3, and the manual is alarmingly clear: 103 octane only.

What's the compression ratio on your scooter?  What octane do you use?  How long?  Any octane-related problems?

Thanks.

George

It has been said that you run the lowest octane that your bike can tolerate without pinging (detonation).  It is possible that the older aircooled desmodues had a low enough compression ratio that you could use 87 octane.  Most modern desmo engines including the the aircooled ones on the other hand have compression ratios greater than 10:1 that it would seem to me necessary to run higher than 87 octane and possibly 92 octane or better.  I  think 103 is not reasonable because it would be inconvenient to try to get that kind of gas at the pump short of using octane boosters on top of premium.

I use premium gas on mine and my compression ratios are: 10:1, 11.5:1 and 12:1?).  My ST4S (with 11.5:1) gets anywhere from 43 to 51 MPG.

I run 93 Octane on mine.  Not sure if bike motors have knock sensors that can retard timing (I suspect not, at least not my bike), so I wouldn't run an octane lower than recommended unless I was in the middle of nowhere and had no choice - in which case I would probably try and get to the closest pump that sells the 93 and start adding it in.  If I can, I may even find some race fuel and mix it in to bring the Octane levels higher.  Higher octane gas prevents pinging/detonation which can damage your engine.  If the motor doesn't need it, it really doesn't do anything.  However, if the motor is designed for it, then running something with a lower octane (especially if there is no knock-sensor to control timing) will risk additonal wear/damage to the motor.

Like CDC my ST4s uses 93. I've never had an issue with performance (he we go..."that's what she said".), but I think consistency is key also (he we go again..."that's what she said".). If you use different fuels your valves with react if the fuel is not up to standard. Valves need all the fuel to be spent when it ignites otherwise a carbon residue is left behind. Over time it builds up and you have problems. Clean fuel (fuel filter helps) will prolong the life of your engine better than anything as related to valves. Shell is the best for that. You can also buy racing fuel at MSR behind the Texaco going up towards the track. Didn't see the cost last weekend but worth the trip to get some...hint hint hint ...Sunday riders! I won't threadjack here.

I've run 87 in my air-cooled motors occasionally without issue, but they have only around a 10.5:1 CR.  My manual for the HM states 91 octane, so my normal fill is 91-93.

Nothing but premium in my bikes

Yeah I only put premium in my bike as well.  Heat can factor in on detonation... one of the reasons you need to run higher octane in turbo engines... and intercool them if possible to keep the temps down for more power and less chance of detonation.  I'd prefer the peace of mind with premium on my nice bike, regardless if it will run on less.

QuoteShell is the best for that

I dunno.  The only time I strayed from my strict Chevron/Texaco(Chevron additives), and used Shell, my bike ran like bunk for a week.  I'm kind of a snob on gasoline.. maybe we all have preferences, but I won't put that stuff in my bike... even though I have a Shell business gas card that could pay it for free.  My Jeep can have it, not my bike.   

Quote from: JesterDFW on October 26, 2008, 05:38:58 PM
The only time I strayed from my strict Chevron/Texaco(Chevron additives), and used Shell, my bike ran like bunk for a week.  I'm kind of a snob on gasoline.. maybe we all have preferences, but I won't put that stuff in my bike

Hmmm...now you have me wondering. I've never had a bunky motor with the fuel. But I might put some Tiger juice in the ST next time. Today for the first time in my short time riding this bike I hit the power band trying hard to keep up with CDC and it caught me off guard when the front wheel came up a little. I was running Shell Premium and sounded like a freaking race engine. But, I'll try something different and see the difference.

Quote from: RED on October 26, 2008, 06:36:10 PM
Hmmm...now you have me wondering. I've never had a bunky motor with the fuel. But I might put some Tiger juice in the ST next time. Today for the first time in my short time riding this bike I hit the power band trying hard to keep up with CDC and it caught me off guard when the front wheel came up a little. I was running Shell Premium and sounded like a freaking race engine. But, I'll try something different and see the difference.

Yeah, when I run that 93 octane stuff, both the front AND the rear wheels come off the ground....   [moto]

Quote from: GeorgeInDallas on October 26, 2008, 06:56:13 PM
Yeah, when I run that 93 octane stuff, both the front AND the rear wheels come off the ground....   [moto]

George, you must be talking about flying a helicopter.

Chevron was one of the first to have their gasoline rated top tier.  BMW and Honda tested their cars on it exclusively so the rumor went.  Shell at least in their premium blend is also now top tier so the rumor goes.

I hope this does not turn out to be an oil war.

Quote from: RED on October 26, 2008, 06:36:10 PM
Hmmm...now you have me wondering. I've never had a bunky motor with the fuel. But I might put some Tiger juice in the ST next time. Today for the first time in my short time riding this bike I hit the power band trying hard to keep up with CDC and it caught me off guard when the front wheel came up a little. I was running Shell Premium and sounded like a freaking race engine. But, I'll try something different and see the difference.

And for the record, I was just trying to keep Tommy from being bored.  Apparently, I was not successful as he kept on passing me while we were in the same lane and on the outside of a left hand sweeper while I was doing 80MPH and he comes around at a 100MPH.  Spooked the hell out of me.  He tried to buy me lunch after that but I told him I was still mad cause he showed me up! 

cdc

I get better gas milage when I use 87, so 87 is all I use.

I don't worry about fuel economy when I ride my Duc, if I did I'd buy a scooter.  I use 93  on all 4 of mine.