If 87 RON is used instead of 95....

[Ajith_K]

.. will the ECU compensate by backing off timing? Or will it mean runaway deto? The bike in question being a HYM 1100 Evo.

[Shazaam]

The use of a lower octane fuel doesn't retard ignition timing.

Different models have different octane requirements. Read your Owners Manual for the RON octane needed. During engine development they instrument the engine to monitor engine knock onset under a variety of expected operating conditions.

The optimum octane rating is actually slightly lower than the Ducati's recommended minimum stated in the owners manual. This is to provide a safety margin in case a particular fuel delivery or brand doesn’t quite reach it's published octane rating or to compensate for environmental effects. The octane requirement is different depending on the weather and your location.

Modern motorcycle engine management systems are designed to adjust automatically to prevent pinging. Variables that affect pinging, such as coolant temperature, ambient air pressure and air temperature, are constantly monitored by the computer to assure best performance.

For example, in the summer when your coolant temperatures run hotter, a water jacket temperature increase of 10 degrees from 160 F to 180 F would normally increase the (R+M)/2 octane number required by 2, which is one gasoline grade higher than recommended. However, the computer has a preset fuel and ignition timing map that tells it to retard the timing to avoid pinging when the temperature is high.

It's important to note that the fuel and ignition map is based on the expectation that you are using the recommended fuel. If you are using a higher than recommended octane fuel, the computer doesn't know and will still temporarily retard the timing. So the computer cannot take advantage of a higher octane fuel unless you reprogram the fuel and ignition map on a dyno.

This approach to preventing engine knock is different than the method auto makers use today. Most cars use knock sensors to directly detect engine knock so if you use a lower than recommended fuel octane you simply get a retarded ignition timing and consequently lower performance, but no knock.

[Chouch]

Owner manual recommend RON 95, which convert to PON 91 in US.

Ron 87 is like banana juice. If your ECU maybe able to do something, I'm quite sure it cant perform miracle and would avoid to put that fuel again.

[Ajith_K]

First off, thank you both for responding. My frustration with the fuel quality regardless, the choice of fuel octane numbers are the chips i am dealt with in my neck of the woods. Most vehicles in India run 10:1 CRs. I was hoping there was a knock sensor in the system. As I was reading the posts i realized that the parts catalog was online. There is a cylinder temp sensor and an intake air temp sensor on the 1100 Evo so i guess i know where i stand with fuel choices.

[air870]

I use either Speed 93 or Extra Premium without any ill effects. Check the RON to Octane conversion equation.

[Ajith_K]

Premium Fuel in India is 91RON and 81MON. Sent a mail to Ducati to determine whether this fuel will work long term but i have no responses yet. With a really small fuel tank, and special fuel needs, the hyper which looked like the most practical Duc in the lineup as far as Indian needs are concerned, is rapidly loosing ground