For those of you that think BRP is in cahoots with the Oil Co's and that is why they say a minimum of 91 Octane is recommended, I think you are all wet and do a disservice to our community.:gaah: The Rotax 998cc engine is a well built engine that puts out more horsepower than, say, a 1200cc Harley engine. One of the reasons for this is that the 12.2:1 compression ratio, of the Rotax engine, gets more air and fuel, hence more power, into the cylinder. The problem with these high compression ratios is that the air/fuel mixture can detonate just from the heat of compression. One way around this problem is to use a fuel type that has an anti-knock compound added to the fuel. This is why BRP(Rotax) recommends a minimum of 91 Octane. Now, if you use a fuel with 87 or 89 Octane your engine might very well "Ping" or "Knock". If your ECM detects pinging, it begins to RETARD THE TIMING until the ping goes away. This is why it may appear that your scoot runs fine with lower octane fuels. With the retarded timing, though, you may not get a complete burn and the result is LOWER POWER for each cycle that utilizes retarded timing.
Using a fuel additive would get around this problem but then the cost-effectiveness might suffer.
So, the 91 Octane recommendation is NOT a plot by BRP to take away your freedoms:lecturef_smilie: but rather is a recommendation to permit you to get the most out of your machine.:clap:
:agree:But some don't want to spend 20/25 cents extra for 91 ,So they try to convince themselves and others that 87 is better;
It's like that movie quote, You don't want to know the Truth.:dontknow: