Will Using 87 Octane impact performance?

[rjinaz86323]

We live in north central AZ. Almost all of our trips involve mountain roads and hot dusty Rez riding to go anywhere. I ran 91 or 93 octane when we first got our Spyder After a while I tried 87 octane and could not tell any difference. So I always use 87 if available. Most of our riding is fully loaded 2up multi week trips. Averaging low-mid 30's on most roads, but a little less on freeways. Out west here most freeways are 75 or 80 speed limit.

[BajaRon]

We live in north central AZ. Almost all of our trips involve mountain roads and hot dusty Rez riding to go anywhere. I ran 91 or 93 octane when we first got our Spyder After a while I tried 87 octane and could not tell any difference. So I always use 87 if available. Most of our riding is fully loaded 2up multi week trips. Averaging low-mid 30's on most roads, but a little less on freeways. Out west here most freeways are 75 or 80 speed limit.

The computer makes any power reduction compensation for lower octane seamless. You're never going to feel it. At higher altitudes, higher octane is counter productive. The difference is going to be greatest below 4,000 ft. and in warm to hot temperatures under load.

[BazF]

Is there anyone else like me who doesn't give a monkies about octanes and gas mileage ?
I just fill it up when it needs it and ride on. I don't know my mpg and don't care.
I have tried putting in different octane ratings and noticed no difference at all in performance.
If you need to be an accountant and worry about pennies to ride then you can't be enjoying it too much.
Baz

[BLUEKNIGHT911]

Is there anyone else like me who doesn't give a monkies about octanes and gas mileage ?
I just fill it up when it needs it and ride on. I don't know my mpg and don't care.
I have tried putting in different octane ratings and noticed no difference at all in performance.
If you need to be an accountant and worry about pennies to ride then you can't be enjoying it too much.
Baz

Well, I'm in the 87 octane camp. (14 1330 RT) However, I do keep track of my MPG's .... WHY!?! ... because if I notice they drop by 5 or more MPG's something isn't right .... It's similar to "my Spyder doesn't stop like it used to" .... WHY?? ... Could be you need to top off the brake fluid; or more importantly, maybe the Brake Pads are getting dangerously LOW! .... good luck ....Mike

[BazF]

Not the same thing Mike, I keep my Spyder maintained and regularly check brakes, tyres, belt etc. I just can't be arsed worrying about a couple of extra mpg or saving pennies on fuel.
Baz

[2dogs]

If I were to suddenly drop 5 MPG I'd certainly look into why. But if other riders had a similar occurrence and didn't care why, I wouldn't judge them for not wondering or caring one way or the other. However, if they incurred a related engine failure I'd certainly stop and help them out.

[Mikey]

Is there anyone else like me who doesn't give a monkies about octanes and gas mileage ?
I just fill it up when it needs it and ride on. I don't know my mpg and don't care.
I have tried putting in different octane ratings and noticed no difference at all in performance.
If you need to be an accountant and worry about pennies to ride then you can't be enjoying it too much.
Baz

I think about ethanol verses nonethanol, more than octane, especially when it gets time to put it up for the winter!

[PMK]

"pennies per gallon" .... in Vt. it's about 70 pennies more for 91.... 40 more for 89 .... As for improved performance/acceleration .....can you give me a % for that improvement or actual Dyno numbers? .....Mike

Mike, for many years, I have read your replies and reasoning in regards to using 87 octane fuel, regardless that the manufacturer, whether determined by Rotax, the engine designer and manufacturer, or BRP the vehicle manufacturer, determined their reasons to state in manuals and placards to burn higher octane rated gasoline.

While I do respect your decision, and may not agree with your ideas, your recent reply post of a few days ago had me consider your words and challenge.

Your words put forth a request that a person that stated running high octane fuel, provide data to prove a need for the higher octane rated fuel.

After considering your words, it seems more applicable that those folks deviating from the manufacturers recommended fuel octane, they should be providing data, with repeatable results, demonstrating no harm to the engine in any way, or performance loss, over the wide and varied ways these machines are utilized.

BajaRon made some very good well accepted criteria where a lower octane may be acceptable, essentially higher altitudes, with less density, ultimately reducing the engines cylinder pressures. Myself, I have never accomplished testing to get a cylinder pressure value from compression testing a good fresh 1330 that is properly broken in. Cylinder pressure, along with other factors, some by mechanical design, others by mapping of the fuel and ignition, plus fuel quality must “play” well together.

As I mentioned, after considering your words for a few days, I hope the lower octane fuel causes no concerns for anyone electing to run it. Modern vehicle engines and the systems that support them are very smart, far more intelligent than the high performance V8 engines with points or no map style electronic ignitions.

Simply not sure whether you or BRP is more correct, but it would be very cool if you had data to support the running of lower than specified octane fuel.

[troop]

I don't know ... In the manuals, BRP requires minimum 87 octane, but recommends 91+ octane. I have to believe that BRP engineers/Rotax engineers and the legal department would clearly state "Requires 91+ octane" if 87 octane would cause any harm to the engine. Plenty of motorcycles require 91+ octane. In regard to efficiency, ethanol free gasoline is a no brainer, and generally also results in a bit more MPG's. Here in Wisconsin, I always store with ethanol free and a stabilizer. Come riding season, I tend to flip/flop between regular/premium fuels. while I do notice a touch better MPG's with ethanol free, I don't feel any performance issue.

[ARtraveler]

This discussion will go "round and round" depending on the current readers.

I have made my comments earlier on but will reiterate one more time.

Early on 2008 when I purchased one of first Spyders...I was a manual reader and a gung ho Spyder guy to the core. I used premium gas (the highest octane) I could get in Alaska...which was 91. Pricing was no big deal. The three grades were always a dime difference. So, premium cost me 20 cents a gallon more. We always had three grades available (except in the bush). There, you took what they had and liked it.

I am NOT a mechanic. However, I have owned seven separate Spyders over 15 year period and put over 200,000 miles on them. I took Blue Knights suggestion a few years later and adopted the use of 87 octane. There was no "ethanol" gas in Alaska during my time there. I moved from Alaska to Arkansas in 2019 where they have a combo 87 octane and ethanol. After my change over to the "death to Spyder" blend, I still noticed NO appreciable engine operation. As Baja Ron has said, the computer adjusts your machine to run on whatever proper octane/ethanol you may choose to use. I never experienced any mechanical issues with my Spyders due to low octane gas. The two gentlemen that purchased our F3L's back in 2023 got some very fine machines. One at 20K miles and the other at 8K miles.

I am no longer involved in the gas wars threads, but thought I would give you my .02 worth. Its free, and I can still post about Spyder stuff.

[BLUEKNIGHT911]

Not the same thing Mike, I keep my Spyder maintained and regularly check brakes, tyres, belt etc. I just can't be arsed worrying about a couple of extra mpg or saving pennies on fuel.
Baz

So if you noticed you were re-filling your gas tank more often than you used to....to go the same distance that wouldn't concern you ???? .... well it's your bike and you are entitled to operate it the way you see fit . ... " ARSED "is that a word from the " down under " folks ???? .....Mike

[BLUEKNIGHT911]

Mike, for many years, I have read your replies and reasoning in regards to using 87 octane fuel, regardless that the manufacturer, whether determined by Rotax, the engine designer and manufacturer, or BRP the vehicle manufacturer, determined their reasons to state in manuals and placards to burn higher octane rated gasoline.

While I do respect your decision, and may not agree with your ideas, your recent reply post of a few days ago had me consider your words and challenge.

Your words put forth a request that a person that stated running high octane fuel, provide data to prove a need for the higher octane rated fuel.

After considering your words, it seems more applicable that those folks deviating from the manufacturers recommended fuel octane, they should be providing data, with repeatable results, demonstrating no harm to the engine in any way, or performance loss, over the wide and varied ways these machines are utilized.

BajaRon made some very good well accepted criteria where a lower octane may be acceptable, essentially higher altitudes, with less density, ultimately reducing the engines cylinder pressures. Myself, I have never accomplished testing to get a cylinder pressure value from compression testing a good fresh 1330 that is properly broken in. Cylinder pressure, along with other factors, some by mechanical design, others by mapping of the fuel and ignition, plus fuel quality must “play” well together.

As I mentioned, after considering your words for a few days, I hope the lower octane fuel causes no concerns for anyone electing to run it. Modern vehicle engines and the systems that support them are very smart, far more intelligent than the high performance V8 engines with points or no map style electronic ignitions.

Simply not sure whether you or BRP is more correct, but it would be very cool if you had data to support the running of lower than specified octane fuel.

I appreciate your concern for my preferring 87 octane over premium ..... But my few special talents do not include being a Fuel engineer, nor am I a typist who uses more than TWO fingers .... I do agree with you about the BRP engineers, just in different way. .... IMHO if those engineers had even the slightest thought that 87 octane would / could harm the engine they might say something like " never use 87 octane in this engine " My views on using 87 octane have been worded as " my opinion " not a reference to engineering studies ......Mike

[PMK]

I don't know ... In the manuals, BRP requires minimum 87 octane, but recommends 91+ octane. I have to believe that BRP engineers/Rotax engineers and the legal department would clearly state "Requires 91+ octane" if 87 octane would cause any harm to the engine. Plenty of motorcycles require 91+ octane. In regard to efficiency, ethanol free gasoline is a no brainer, and generally also results in a bit more MPG's. Here in Wisconsin, I always store with ethanol free and a stabilizer. Come riding season, I tend to flip/flop between regular/premium fuels. while I do notice a touch better MPG's with ethanol free, I don't feel any performance issue.

Not near our Spyder. Curious, the placard under the seat, does it have the octane spec on it?

[PMK]

I appreciate your concern for my preferring 87 octane over premium ..... But my few special talents do not include being a Fuel engineer, nor am I a typist who uses more than TWO fingers .... I do agree with you about the BRP engineers, just in different way. .... IMHO if those engineers had even the slightest thought that 87 octane would / could harm the engine they might say something like " never use 87 octane in this engine " My views on using 87 octane have been worded as " my opinion " not a reference to engineering studies ......Mike

Certainly. You requested to another person that posted a reply, that they provide data showing performance validating the higher octane be used.
My opinion is, if someone endorses, with their opinion, self admitting not being a fuel engineer, to run a lower octane fuel, not in compliance with the manufacturers published specifications, then the burden of proof, via reliable proven data, falls on the person suggesting the, in ARTravellers words, “Death to Spyder” fuel of a lower than manufacturer rated octane.

[troop]

Not near our Spyder. Curious, the placard under the seat, does it have the octane spec on it?

Just checked ... Shows minimum 91 octane.

[PMK]

This discussion will go "round and round" depending on the current readers.

I have made my comments earlier on but will reiterate one more time.

Early on 2008 when I purchased one of first Spyders...I was a manual reader and a gung ho Spyder guy to the core. I used premium gas (the highest octane) I could get in Alaska...which was 91. Pricing was no big deal. The three grades were always a dime difference. So, premium cost me 20 cents a gallon more. We always had three grades available (except in the bush). There, you took what they had and liked it.

I am NOT a mechanic. However, I have owned seven separate Spyders over 15 year period and put over 200,000 miles on them. I took Blue Knights suggestion a few years later and adopted the use of 87 octane. There was no "ethanol" gas in Alaska during my time there. I moved from Alaska to Arkansas in 2019 where they have a combo 87 octane and ethanol. After my change over to the "death to Spyder" blend, I still noticed NO appreciable engine operation. As Baja Ron has said, the computer adjusts your machine to run on whatever proper octane/ethanol you may choose to use. I never experienced any mechanical issues with my Spyders due to low octane gas. The two gentlemen that purchased our F3L's back in 2023 got some very fine machines. One at 20K miles and the other at 8K miles.

I am no longer involved in the gas wars threads, but thought I would give you my .02 worth. Its free, and I can still post about Spyder stuff.

Focusing on your words referencing BajaRon mentioning the computer making the adjustments based on fuel octane, that becomes a slippery slope regarding modern performance engines.
In simple terms, skirting and avoiding the technical merits, demerits and mumbo jumbo for those folks with more rider in them than maintenance tech, the onboard computer monitors many parameters. In doing so by monitoring at a rapid rate, the computer has only a few parameters it can instantly make adjustments for.
One being lack of oil pressure. Generally that results in engine shut down. Happens instantly and for good reason.

In regards to fuel octane, the engine computer does not monitor the octane rating. The engine computer should be constantly making adjustments, of ignition timing, based off input from many variables. Those variables, except one, are slow reacting tuning parameters. When a sensor, determines a knock, or technically, detonation, ignition timing is immediately retarded to prevent catastrophic damage. As ignition timing is altered, all other parameters must “fine tune”, or “reset” so they all play within the harmony derived by the engine management engineers.

That said, the slow reacting tuning by the engine computer, can take many hours or miles, then once “dialed in”, the adjustments made are very minor. This slow to adjust process is one reason why there can be a minimal performance change noted within the first few miles of not only lower octane, but also exhaust mods, air filter mods, new spark plugs, or even disconnecting the battery.

If a true comparison of octane were to happen, it can not be on a tank to tank fill up. Rather it would require say 100 miles on one fuel, then after completely purging the system with the next fuel, again, allow the engine computer say 100 miles to optimize the parameters. The entire tuning process can be very complicated.
All the best and hopefully the applicable items will carry over to your daily driver, or the Aston Martin.

[PMK]

Just checked ... Shows minimum 91 octane.

Thank you.
In theory, that placard should be the most current spec at time of delivery, to obtain acceptable advertised performance AND compliance of environmental emissions specs for the date of manufacture.

As we know, increasing fuel octane above the recommended amount, can decrease performance.

[ARtraveler]

Bottom Line:

Keep it friendly and don't forget the site rules about posting.

[IdahoMtnSpyder]

If a true comparison of octane were to happen, it can not be on a tank to tank fill up. Rather it would require say 100 miles on one fuel, then after completely purging the system with the next fuel, again, allow the engine computer say 100 miles to optimize the parameters. The entire tuning process can be very complicated.
All the best and hopefully the applicable items will carry over to your daily driver, or the Aston Martin.

Refer to my post #143 above. My experience over two summers is probably as close to an objective comparison as you'll be able to find in the SL world. It shows that as far as MPG is concerned there is no practical difference between regular and premium. This makes sense when you consider that both octanes have virtually identical energy content. My original discussion is here: https://www.spyderlovers.com/forums/...remium+mileage.

I have not seen anyone post photos of two engine tear downs, one that ran only 87 octane and one that ran only 91 octane. Until we see what the engine internal condition is like for the two octanes we cannot definitely state that 87 octane harms the engine. I don't recall anyone on here reporting engine damage from using 87 octane. I argue that ROTAX engineers have done a damn good job of designing the Spyder 1330 to be able to tolerate the combustion differences between the two octanes.

[racoon]

I've seen a number of other vehicle websites that have had discussions about manufacturer recommended octane ratings for fuel.

Here's what the US Government's Department of Energy says about octane:

https://www.fueleconomy.gov/feg/octane.shtml

Higher octane fuels are often required or recommended for engines that use a higher compression ratio...

There are also warnings about knocking and pre-detonating and other dire warnings, including one about possibly damaging the engine.


But if I look in my Spyder Operators Guide (page 176 of the 2024 guide), it says:

Fuel:
Minimum octane:
87 Pump Posted AKI (RON+MON)/2
92 RON

Recommended octane:
91 Pump Posted AKI (RON+MON)/2
95 RON


I think the important thing to remember is that octane is not a measure of the amount of energy in the gasoline. It's a measure of the stability of the fuel, and how it reacts to being compressed. Higher compression engines need higher octane fuels.

[Dasmoetorhead]

I run 93 octane ethanol free. My money my decision.

[BLUEKNIGHT911]

Just checked ... Shows minimum 91 octane.

Well, that's interesting .... I went out and checked my 2014 RT which has the 1330 engine .... and after getting a magnifying glass out, I could read that sticker and yep, it says minimum 91 Octane .... I wonder why the owner's manual says "91 Octane RECOMMENDED"????? I'd be interested to know if that's what's needed to PASS the Emissions standards? There is information on that sticker that refers to emission requirements, as opposed to what the engine actually requires to function safely .... JMHO .... Mike

[Mikey]

I hate to be a little birdie here and throw in another thing that seems to me has been forgotten here, is that BRP has to fall within the emission laws. Also, if I am not mistaken, to do that it probably falls in that 91 range. But they say it's ok to run 87, as a min! I mean, if running 87 was detrimental to our bikes, there would be a whole lot of us blown up by now. Gas, tires, and oil, all subjects that can be discussed to the end of time. Use what works for you!

[PMK]

When Rotax designed, built, and supplied Can Am with engines, the design team very likely tested to 100% max performance intended.

More than likely, that team determined that 91 octane fuel is not harmful and provides both reliability and performance, some intertwined towards emissions. At a guess, the lower octane fuel gave a substandard result somewhere within that 0% to 100% max performance.

As a group of owner riders, it is known that each has a different level of comfort with regard to how we ride, and with that, how we situate on the performance between 0% and 100% engine output amount.

Regarding all reciprocating internal combustion engines, those run at lower power settings do not create high cylinder pressures. With these lower cylinder pressures at partial throttle, detonation is nowhere near the possibility of when the engine is running with high cylinder pressures at a greater throttle setting, towards or at 100%, with higher rpm.

That said, in less stressful operation, lower octane fuel may never be an issue. When extracting more from that engine, especially greater load with accompanying more open throttle, there becomes the possibility that low octane fuel will fail.

As riders, we sometimes hear, ride within your comfort zone - same with the engine, operate it within its comfort zone. That level of comfort may well be within reach of 87 octane for many. Those that truly push the engine towards 100% output could be outside 87 octane's anti knock range.

[BazF]

Polite way would be 'can't be bothered'