What octane fuel you using?

[_imp]

I read in the Aussie manual that 91 was required, so that is why I was using it. Then read in the US manual 86+ was OK.

Funny but the FZ8 also is fine on 87 according to the manual.

Aussie might be one of the countries that use a different scale for their gas numbers.

Aussie might be one of the countries that use a different scale for their gas numbers.
They do, they use the European system of octane rating. Their 91 is our 87. Using a higher octane fuel than is required for a stock engine will do absolutely nothing for you besides cost more money. As mentioned, if you want to pay more, find 100% gasoline and use that, you will actually get better performance that way (only about 3-4%, but it's also better for the engine). If your fuel says "may contain up to 10% ethanol", you can bet it has 10% ethanol in it.

This is one of those internet arguments that happens constantly and consistently, with everyone going round and round on it.

Aussie might be one of the countries that use a different scale for their gas numbers.
They do, they use the European system of octane rating. Their 91 is our 87. Using a higher octane fuel than is required for a stock engine will do absolutely nothing for you besides cost more money. As mentioned, if you want to pay more, find 100% gasoline and use that, you will actually get better performance that way (only about 3-4%, but it's also better for the engine). If your fuel says "may contain up to 10% ethanol", you can bet it has 10% ethanol in it.

This is one of those internet arguments that happens constantly and consistently, with everyone going round and round on it. This is exactly correct with respect to the Aussie/UK octane rating but not entirely accurate with respect to being able to get more out of the higher octane. Some engines have built-in knock sensors and can automatically adjust ignition timing to take advantage of the higher rating. My FJ Cruiser is one of them but there are many others. The documentation from Toyota specifies this. Since Honda didn't tell us about the speed limiter it's possible that other features are built in that we wouldn't know about either.

Aussie might be one of the countries that use a different scale for their gas numbers.
They do, they use the European system of octane rating. Their 91 is our 87. Using a higher octane fuel than is required for a stock engine will do absolutely nothing for you besides cost more money. As mentioned, if you want to pay more, find 100% gasoline and use that, you will actually get better performance that way (only about 3-4%, but it's also better for the engine). If your fuel says "may contain up to 10% ethanol", you can bet it has 10% ethanol in it.

This is one of those internet arguments that happens constantly and consistently, with everyone going round and round on it. This is exactly correct with respect to the Aussie/UK octane rating but not entirely accurate with respect to being able to get more out of the higher octane. Some engines have built-in knock sensors and can automatically adjust ignition timing to take advantage of the higher rating. My FJ Cruiser is one of them but there are many others. The documentation from Toyota specifies this. Since Honda didn't tell us about the speed limiter it's possible that other features are built in that we wouldn't know about either.
That's not how the knock sensor works... your FJ Cruiser engine is designed for 91 octane and that's when you get the most power. The anti-knock sensor *lets* you use lower octane. You aren't unlocking "hidden" power by using higher octane gas, you're just using what you're supposed to be.

Here's the test: Go and get race fuel, then have it dyno'd.

I am willing to bet that it will *not* increase your horsepower. I will make this offer to anyone here in the South, actually: If you go and do 3 runs using 87, 91, and 95+ octane fuel with a stock vehicle, I will meet you for the runs. If the dyno shows a larger increase than standard margin of error on race fuel, I will pay for the runs and buy you a 12-pack. If it doesn't, you pay for the runs and a 12-pack.

Using higher octane gas than your engine is DESIGNED TO USE, will not gain you a single thing but a higher bill at the pump.

I don't think anybody has disagreed with this. I'm an automobile dealer of 25 years and have sat through countless training courses having the latest and greatest new tech explained to us by factory reps. I'll use some examples. The Chevrolet Silverado is designed to use 87 octane gas and it has knock sensors that can retard ignition timing. On a dyno it will not produce more power if you put 91 octane in it. The Toyota FJ Cruser is designed to run on 87 or 91. It also has knock sensors that retard and advance ignition timing. The FJ will produce more horsepower on 91 octane than it will on 87 octane because it will advance ignition timing to the threshhold of detonation. I don't know how far their system will keep going and if it would make more power with 110 octain race fuel but it's possible.

One of my hobbies is racing the standing mile in my Ford GT and I've spent a ton of time on the dyno with a laptop messing with ignition advance, boost, and air/fuel ratios. It's easy to see how power rises and falls with changes in ignition advance alone and the objective is to advance it as far as possible without causing detonation. On 91 octane pump gas my GT puts 865 HP to the rear wheels, with the 93 octane fuel available in many parts of the country my GT can run a couple more points of ignition advance and then it puts down 910 HP. The GT has no knock sensors and ignition advance is not automatic so I have to change it with a handheld tuner but in other cars like the FJ it's done constantly and automatically.

For a real ride, on race day, I run 116 octane VP leaded race fuel (about $28 a gallon) and my twin turbo Heffner Ford GT put 1146 HP to the rear wheels. From a standing start at the Texas Mile it accelerated from 0 to 221mph in 26 seconds. The higher octane allows both more boost and more pre ignition advance.

In short and to get back to the point, some new cars have very high compression and so they rely upon their engine electronics to retard ignition timing to prevent detonation. They will make more HP on a dyno using 91 than they will with 87. Some other cars don't have such systems and assuming they don't detonate on 87 octane, they won't make any more power with 91 or 93.

A couple things are absolute however. 1. Changing ignition advance changes horsepower, whether it's changed automatically by the car itself or by the owner using a tuner. 2. Octane is a measure of a fuels resistance to detonation (it is not a measure of energy or power) and if an engine has both higher octane fuel AND the ability to change it's operating parameters to take advantage of the additional resistance to detonation, it will make more power on higher octane gasoline.

I can almost guarantee you that none of this applies to the CB1100 because I'm pretty certain it doesn't have knock sensors. Cheers.

Chip

I don't think anybody has disagreed with this. I'm an automobile dealer of 25 years and have sat through countless training courses having the latest and greatest new tech explained to us by factory reps. I'll use some examples. The Chevrolet Silverado is designed to use 87 octane gas and it has knock sensors that can retard ignition timing. On a dyno it will not produce more power if you put 91 octane in it. The Toyota FJ Cruser is designed to run on 87 or 91. It also has knock sensors that retard and advance ignition timing. The FJ will produce more horsepower on 91 octane than it will on 87 octane because it will advance ignition timing to the threshhold of detonation. I don't know how far their system will keep going and if it would make more power with 110 octain race fuel but it's possible.

One of my hobbies is racing the standing mile in my Ford GT and I've spent a ton of time on the dyno with a laptop messing with ignition advance, boost, and air/fuel ratios. It's easy to see how power rises and falls with changes in ignition advance alone and the objective is to advance it as far as possible without causing detonation. On 91 octane pump gas my GT puts 865 HP to the rear wheels, with the 93 octane fuel available in many parts of the country my GT can run a couple more points of ignition advance and then it puts down 910 HP. The GT has no knock sensors and ignition advance is not automatic so I have to change it with a handheld tuner but in other cars like the FJ it's done constantly and automatically.

For a real ride, on race day, I run 116 octane VP leaded race fuel (about $28 a gallon) and my twin turbo Heffner Ford GT put 1146 HP to the rear wheels. From a standing start at the Texas Mile it accelerated from 0 to 221mph in 26 seconds. The higher octane allows both more boost and more pre ignition advance.

In short and to get back to the point, some new cars have very high compression and so they rely upon their engine electronics to retard ignition timing to prevent detonation. They will make more HP on a dyno using 91 than they will with 87. Some other cars don't have such systems and assuming they don't detonate on 87 octane, they won't make any more power with 91 or 93.

A couple things are absolute however. 1. Changing ignition advance changes horsepower, whether it's changed automatically by the car itself or by the owner using a tuner. 2. Octane is a measure of a fuels resistance to detonation (it is not a measure of energy or power) and if an engine has both higher octane fuel AND the ability to change it's operating parameters to take advantage of the additional resistance to detonation, it will make more power on higher octane gasoline.

I can almost guarantee you that none of this applies to the CB1100 because I'm pretty certain it doesn't have knock sensors. Cheers.

Chip +1
If a vehicle's computer can adjust ignition timing relative to octane/knock, then you get more power. Does the CB have it? Don't know but even if improbable, it's not impossible. Does seem more likely for an air-cooled engine which is more prone to hot spots in the combustion chamber on warm or hot days.

There is no knock sensor.

But how do you know this?