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Registered Users
 everyones a rocket scientist
87 or 91 who know everyones got a different opinion about it. the way i figure it. use what makes u happy cause everyone has a different opinion on the subject
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No problems running on 87 
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Registered Users
Scotty...just wanted you to know I've enjoyed your responses to the many posts since the Spyder forum began. You are a gold mine!
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Now now - let's not get personal here and start attacking.
Everyone is welcome to their opinion. Some opinions are based on facts, and some on fiction - but they are each persons opinion.
Rather than waste time attacking out here, if you really want to learn about octane - take 30 minutes and do some reading out here on the net.
You will find that you are correct when you say "I wouldn't add it to a vehicle that I didn't think would benefit from it either...."
Some vehicles certainly can benefit from running premium, the Spyder just isn't one of them - according to the people that designed it.
There is plenty of scientific data available on the internet that proves higher octane can not improve power or MPG unless used in an engine that specifically requires it. The Spyder doesn't (pg 22 of owners manual).
Those engines that do require it don't get more power or mpg from the fuel or the higher octane - they simply require the higher octane in order to run smoothly without knocking.
Other engines may have anti-knock systems in place to keep them running smoothly. It's simply two different solutions to the same problem in order to keep the engine running smooth. High compression engines, turbo and super charged engines may very well require the higher octane to solve the knocking problem. The Spyder engine doesn't fall into those catagories.
The error in this whole arguement is that many incorrectly think that higher octane gas has more useable power in it - it doesn't. Basic physics will tell you that you cannot get more power from something than it contains, and 87 and 91 octane gasses have identical amounts of power in them.
If you have firm scientific data (dyno and mpg readings taken in a controlled environment with calibrated equipment) that shows the Spyder to get better MPG or have more power when running premium gas, I'm sure the engineers at BRP would appreciate you sharing this data.
Seat of the pants dyno or gas-pump mpg readings without consistent riding done in a controlled environment are just not accurate enough to be taken as proof.
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Motorbike Professor
 Originally Posted by boogllasti
Those engines that do require it don't get more power or mpg from the fuel or the higher octane - they simply require the higher octane in order to run smoothly without knocking.
Actually, some get more power and mpg. My wife's Chevy HHR is one of them. Considerable improvement in power (not tested) and mpg (long-term records). This is a result of the engine management system. This thing will run on regular without knocking a bit. The computer adjusts it, and you don't notice any problems at all. It comes alive with premium, however, and the mileage goes up at least 2 mpg. Doesn't downshift as much in cruise control on the freeway, either. If you put 12,000 miles on a vehicle a year, and average 25 mpg, the cost is less than $100 more. Use what makes you happy, just don't expect miracles unless the vehicle is designed to need premium.
-Scotty
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"Again, as I've said in a previous post, if the Spyder has a knock control system, it would make corrections long before you heard any knocking. Since we have no access to the ECM as end users or even at the dealer level for this issue, I haven't learned if it does or not. Because we don't hear about knocking issues, and the fact that BRP invested a lot of effort in other advanced systems, I'm assuming that it does. If that is the case, and higher octane fuel prevents the detonation in the first place, I end up with more power, period."
Two different ways to solve the knocking problem : Anti-knock system or higher octane.
Assuming you are correct that the Spyder uses the first solution - the problem is already solved by the knock-control system. Why would you need to solve the problem again with higher octane?
Maybe you have something wrong with your Spyder if you're having such knocking issues. I would have your dealer check things out - maybe your knock-control isn't working properly?
I've not heard of a single case of engine knock on the Spyder, but there's always a first for everything. Perhaps your dealer can figure out the problem at your 6,000 checkup.
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Originally Posted by boogllasti
Assuming you are correct that the Spyder uses the first solution - the problem is already solved by the knock-control system. Why would you need to solve the problem again with higher octane?
I think you're missing the point...
A knock-control system retards ignition timing to mitigate or eliminate knock. Retarding ignition timing (without changing other engine parameters) has the side-effect of reducing engine power output. *If* the Spyder's engine control system incorporates a knock sensor which must continually retard ignition timing to prevent knock while using the min recommended 87 octane fuel, it stands to reason reducing or eliminating the knock by increasing the fuel's octane negates the need to retard ignition timing in the first place. In this case, switching from 87 octane to 91 octane doesn't result isn't more engine power being produced, per se, but it will eliminate the artificial reduction of produced engine power imposed by the engine control system when it retards ignition timing to prevent knock.
This entire discussion is speculative until we ascertain whether the Spyder incorporates a knock sensor. That being said, it seems to me BRP would not have published a minimum octane in the Operator's Guide if the Spyder's engine control system incorporates a knock sensor. Theoretically, the knock sensor would compensate for lower octane fuels by simply further retarding the timing. Additionally, for a vehicle marketed and sold in large part based on its performance, one wonders why BRP fails to mention the potential power and economy gains available by simply using higher octane fuel -- especially considering the Spyder's lackluster fuel mileage.
Regards,
Mark
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There is a limit on how far the ignition timing can be retarded. A computer controlled "anti knock sensor" can not do miracles. It has to be designed to ONLY retard the timing to the point where decent drivability still exists. These days, with the high cost of gasoline, manufacturers who adverise that minimum regular 87 octane gas can be used add a selling point to their product. Will the vehicle run best on 87....not always. Given the Spyders high compression ratio I would not use any fuel under 93 octane in it.
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I have it on good authority that the factory system DOES NOT have knock detection. I also checked the parts book and no knock sensor that I could find.
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I found this previous post by Magic Man.
Hope this is okay to re-post?
Not sure what more proof one would need.
I also tried a tank of 93 and found it didn't run as well.
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From Magic Mans previous post:
The lower compression of this series of 990 Rotax as compaired to the 136hp version coupled with the higher flash point of the 93 octane fuel can actually make the Spyder have some driveability problems at lower RPMs. This we actually have experienced first hand in our own test on our Spyder last weekend.
We filled up an almost empty tank with 93 and drove the bike. After a few minutes when the 87 fuel was completely out of the fuel rail and lines the bike began to have a low speed "miss" or "stumble" that was not there before.
We went back to the shop siphoned out the fuel till no bars were shown went and refilled the tank with 87. Again after a few minutes when the fuel lines and rail were clear of the 93 the "miss" or "stumble" was gone.
There have been several automotive tests and service bulletins on this topic for just the same reason. The higher octane fuel can indeed cause drivability problem in todays engines designed to use the lower octane, lower flash point fuel. Higher octane fuel that is designed to "resist engine knock" or detonation, also has a reluctance to burn properly at low engine speeds because of the lower compression chamber pressures in todays low compression motors.
The higher a fuels octane number the greater it's resistance to pre-ignition it has. Diesel fuel has an octane number over 600 but would not even run in a Spyder as you all know. Unfortunately that higher octane of 93 fuel can also make the flame front spread too slowly in low compression motors causing these types of problems. Especially, at lower engine speeds when compression chamber pressures are at there lowest due to reduced volumetric efficiency of the motors at these engine speeds.
I did this test this last weekend to finally be sure once and for all that indeed it was running worse on the higher flash point 93, and to tell you the truth it really does not run as well at all.
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Originally Posted by spyryder
I have it on good authority that the factory system DOES NOT have knock detection. I also checked the parts book and no knock sensor that I could find.
I was going to suggest someone look to see if there is a knock sensor part number. I am VERY, VERY disappointed that BRP doesn't have knock protection, for as much as we are paying for these bikes and the technology they did put into it I think they dropped the ball big time.
since the spyders don't have knock protection I will put higher octane fuel in my bike.
Mark
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when I get my spyder I will take it to the race track and run the 1/4 mile with both 87 and 91 octane, I will also look for driveability on the way to the track
Mark
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Originally Posted by HDXBONES
My thoughts are that 87 octane is recommended in large part to meet emission requirements. Because it burns faster, combustion would be more complete by the end of the power stroke, compared to higher octanes, lowering hydrocarbon production. Especially at the lower rpm's and throttle positions that they are tested at. As a manufacturer, BRP couldn't recommend actions that would violate emission standards. (My 04 Hemi pickup (that required a minimum of 89 octane at 10:1 compression) had a second set of spark plugs in each cylinder that functioned only at idle to ensure a more complete burn to meet emissive req's.) Higher AFR's and lower octane ratings may be how BRP manages the regulations...
Where did you hear that about the HEMI??? I've got an '05 300C HEMI which I've owned since new and I assure you that all 16 of those plugs are firing....except when the multi-displacement system (which your truck doesn't have btw) cuts out 4 of the cylinders.
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Registered Users
Originally Posted by boogllasti
Now now - let's not get personal here and start attacking.
Everyone is welcome to their opinion. Some opinions are based on facts, and some on fiction - but they are each persons opinion.
Rather than waste time attacking out here, if you really want to learn about octane - take 30 minutes and do some reading out here on the net.
You will find that you are correct when you say "I wouldn't add it to a vehicle that I didn't think would benefit from it either...."
Some vehicles certainly can benefit from running premium, the Spyder just isn't one of them - according to the people that designed it.
There is plenty of scientific data available on the internet that proves higher octane can not improve power or MPG unless used in an engine that specifically requires it. The Spyder doesn't (pg 22 of owners manual).
Those engines that do require it don't get more power or mpg from the fuel or the higher octane - they simply require the higher octane in order to run smoothly without knocking.
Other engines may have anti-knock systems in place to keep them running smoothly. It's simply two different solutions to the same problem in order to keep the engine running smooth. High compression engines, turbo and super charged engines may very well require the higher octane to solve the knocking problem. The Spyder engine doesn't fall into those catagories.
The error in this whole arguement is that many incorrectly think that higher octane gas has more useable power in it - it doesn't. Basic physics will tell you that you cannot get more power from something than it contains, and 87 and 91 octane gasses have identical amounts of power in them.
If you have firm scientific data (dyno and mpg readings taken in a controlled environment with calibrated equipment) that shows the Spyder to get better MPG or have more power when running premium gas, I'm sure the engineers at BRP would appreciate you sharing this data.
Seat of the pants dyno or gas-pump mpg readings without consistent riding done in a controlled environment are just not accurate enough to be taken as proof.
In the factory service manual BRP doesn't recommend 87 octane, they recommend, " a MINIMUM of 87 octane." Everyone is going to interperet it differently but I take that to mean this is the very minimum you should try to get by with, not the best thing you can use! I also believe that premium and high octane are two different things and I just can't help but think that a 10.7:1 compression engine spinning at 10,000 RPM, wouln't benefit from a higher octane or a premium fuel.
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Registered Users
Originally Posted by HDXBONES
My thoughts are that 87 octane is recommended in large part to meet emission requirements. Because it burns faster, combustion would be more complete by the end of the power stroke, compared to higher octanes, lowering hydrocarbon production. Especially at the lower rpm's and throttle positions that they are tested at. As a manufacturer, BRP couldn't recommend actions that would violate emission standards. (My 04 Hemi pickup (that required a minimum of 89 octane at 10:1 compression) had a second set of spark plugs in each cylinder that functioned only at idle to ensure a more complete burn to meet emissive req's.) Higher AFR's and lower octane ratings may be how BRP manages the regulations...
BRP doesn't recommend 87 octane, they recommend a MINIMUM of 87 octane!
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My Nissan has had the double plug setup for years - and they fire all the time - and it runs on 87 as recommended by Nissan.
While I'll be installing my Veypor vr2 this weekend so I can test 1/4 mile, hp, etc. - I'm not going to bother trying premium gas again. I tried it and had the exact same results that Magic Man did.
To measure and noticable difference in HP or MPG it would take a consistent environment, accurate riding patterns and good measuring devices.
Does anyone know if the high-compression 135hp version of this Rotax requires premium?
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Registered Users
Originally Posted by boogllasti
"Again, as I've said in a previous post, if the Spyder has a knock control system, it would make corrections long before you heard any knocking. Since we have no access to the ECM as end users or even at the dealer level for this issue, I haven't learned if it does or not. Because we don't hear about knocking issues, and the fact that BRP invested a lot of effort in other advanced systems, I'm assuming that it does. If that is the case, and higher octane fuel prevents the detonation in the first place, I end up with more power, period."
Two different ways to solve the knocking problem : Anti-knock system or higher octane.
Assuming you are correct that the Spyder uses the first solution - the problem is already solved by the knock-control system. Why would you need to solve the problem again with higher octane?
Maybe you have something wrong with your Spyder if you're having such knocking issues. I would have your dealer check things out - maybe your knock-control isn't working properly?
I've not heard of a single case of engine knock on the Spyder, but there's always a first for everything. Perhaps your dealer can figure out the problem at your 6,000 checkup.
A knock sensor doesn't solve the problem, it just relieves the symptoms. It prompts the computer to retard timing which reduces knock but at the same time reduces power!
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Registered Users
Originally Posted by SpyderMark
I think you're missing the point...
A knock-control system retards ignition timing to mitigate or eliminate knock. Retarding ignition timing (without changing other engine parameters) has the side-effect of reducing engine power output. *If* the Spyder's engine control system incorporates a knock sensor which must continually retard ignition timing to prevent knock while using the min recommended 87 octane fuel, it stands to reason reducing or eliminating the knock by increasing the fuel's octane negates the need to retard ignition timing in the first place. In this case, switching from 87 octane to 91 octane doesn't result isn't more engine power being produced, per se, but it will eliminate the artificial reduction of produced engine power imposed by the engine control system when it retards ignition timing to prevent knock.
This entire discussion is speculative until we ascertain whether the Spyder incorporates a knock sensor. That being said, it seems to me BRP would not have published a minimum octane in the Operator's Guide if the Spyder's engine control system incorporates a knock sensor. Theoretically, the knock sensor would compensate for lower octane fuels by simply further retarding the timing. Additionally, for a vehicle marketed and sold in large part based on its performance, one wonders why BRP fails to mention the potential power and economy gains available by simply using higher octane fuel -- especially considering the Spyder's lackluster fuel mileage.
Regards,
Mark
I know I maybe interpereting it wrong but I'm glad to see that you noticed MINIMUM octane rating too.
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Very Active Member
I "borrowed" a set of water injectors from a Merlin engine and run 100 LL fuel that passes through a magnetic IR filter. Each cylinder exhaust port is routed through a "Y" collector check valve with half the exhaust exiting normally, while the other half runs through a carbon scrubbing hepa filter and cryogenic chamber then directly to the airbox. The rear pulley has been removed and replaced with a speed tensioning pulley with a 75 mph break-out that has a sin-wave inhibitor signal to allow for speeds in excess of 175 mph.
 In the twisties I was playing the tart...
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Make sure you add a mixture of high S-value phenylhydrobenzamine and 5% reminative tetryliodohexamine, other wise you may crack a girdlespring .
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Very Active Member
Maybe, but you have to go through NASA training school first. I will let you borrow the stratosphere suit, but you have to bring your own diapers.
In the twisties I was playing the tart...
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Originally Posted by HDXBONES
My thoughts are that 87 octane is recommended in large part to meet emission requirements. Because it burns faster, combustion would be more complete by the end of the power stroke, compared to higher octanes, lowering hydrocarbon production.
I would argue this to be true for an engine without a knock sensor -- an engine incapable of modifying ignition timing to compensate for octane.
*IF* the Spyder's engine control system does not use a knock sensor, and its ignition timing is optimized for 87 octane, using a higher octane would result in an incomplete combustion event and higher hydrocarbon emissions as you noted.
If, on the other hand, the Spyder *DOES* incorporate a knock sensor, the engine control system would advance timing when switching from lower octane to higher octane fuels allowing more time for the combustion event. In this case, there shouldn't be much difference in hydrocarbon emissions.
An incomplete combustion event results in more than just increased hydrocarbon emissions including:
- Lower economy (because you exhaust unburned fuel)
- Lower power (unburned fuel exhausted wasn't used to make power)
- Higher combustion chamber deposits (I'm sure as an A&P you've cleaned your share of dirty plugs )
I'm sure there are more, but I've only had one cup of coffee so far...
Regards,
Mark
Last edited by SpyderMark; 09-26-2008 at 11:58 AM.
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this would have been a great question to have asked Sunday during the live chat.
Mark
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