Guys
i got this from dyno-tech. Read it & weep!!!!
Polaris and Bombardier are using detonation sensing technology on some of their engines to help alert us while riding or dyno testing, and to try to protect sled owners who experience detonation on their engines. They utilize engine noise pickups bolted to the cylinder head surface and some computer tries to recognize some new loud vibration as possible deto, and adds fuel and/ or retards timing to reduce combustion chamber temperature. Lower temperature (and reduced HP) should eliminate the detonation and all is well.
Bombardier is smart, and has programmed their newest computers to recognize and remember detonation, even to the point of going into a permanent, dealer-only removable fail-safe mode if severe engine knock occurs. This way they might have the option of avoiding responsibility if the owner of a new XP800R detos a piston/ cylinder on 75 octane gas unknowingly used by the sled owner.
75 octane?
I use that low octane rating rating as an example since 75 was the lowest octane test result done by Dateline NBC on 85 samples of "name brand" high test gasoline purchased in California. In that sample group, 11 were substandard, well below the octane posted on the pump.
Since then there have been more eye-opening reports of octane fraud at the pump. Car and Driver magazine reports that of 2816 samples of "high test" gasoline tested the previous year in Michigan by the Bureau of Weights and Measures, 217 failed because of "low octane". Just last week the Today Show did a segment on NY State gasoline cheating, stating that 85% of gasoline tested this winter in NY was substandard. Roll the dice.
Digesting that information, we can assume that 10% of the time, when we fill our sleds with high test, we get boned with 87 or worse. This is no problem for most stock sleds which have safe BSFC and excellent cooling systems. But some high performance stockers that have marginal cooling systems (to save weight and cost) seem to be susceptible to detonation. My opinion is that the new Arctic Cats which have "reverse cooling" (heads get the cold water first like modern automotive performance street and race engines) are most resistant to detonation, and can run higher HP on pump gas than most others. I have no actual hard data, just feedback from many 100's of dyno users who run powerfully on the lakes and trails.
Now that we can enlist SkiDoo dealer Jim Cooper to monitor engine conditions during dyno testing SkiDoo engines, we see even light to moderate deto on his computer before things get bad (either going into "safe mode" or actually eroding a piston. We let Jim's deto meter go up to maybe half way before detuning. Richard Lavanant brought "93" octane gas from PA before doing stage tuning on his new XP800R. Bone stock with bone stock jetting Richard's engine made Jim Cooper's deto meter rattle hard to the right on his gasoline. Richard fulled a jug with 93 from the gas station near the dyno, and that detonation was gone.
This same problem occurred with an XP860R big bore tested on my dyno a few weeks ago. This anonymous owner brought five gallons of "93" from his uncle's gas station in Rochester, and that gas pegged Jim Cooper's deto meter instantly with "safe" jetting! That problem also went away with gas from around the corner from the dyno. Now the uncle knew that his nephew was coming to dyno his sled, and I would think that if he was knowingly selling 87 for 93 he would have suggested that his nephew use different gas. In that case I'm betting that the gas wholesaler could be the culprit. Think of the extra $ people make for selling 87 as 93! How about the bar on the trail with above ground tank with "93" written in Magic Marker on the pump?
I get calls/ emails too often from people who have tuned closely for max "93" performance, wondering about mysterious, sudden detonation after many miles of dandiness. Always, something has differed from those good times. Leaner mixture? Hotter engine? Longer time at WOT? Usually it's the gas.
So what are we to do? The deto protection on Polaris' and SkiDoos is better than nothing, but not perfect. Extended periods of light occasional detonation, seemingly deemed acceptable by the sleds' computer, can gradually overheat pistons as the random "hits" of deto scour away the cooling boundary of air protecting the aluminum pistons (1200 degree melting point) from the 5000 degree flame. Pistons grow and sieze on "four corners", or actually melt just before they seize, because of the loss of that cooling boundary of air. New piston, new nickasil, all because some greedy wholesaler or retailer wanted to pocket an extra $2 per sled tankful.
So what can we do? Octane boosters so far have proven useless to me. My own motor octane tester is a 2000 Silverado 5.3 with twin GT25 Garrett turbos and completely stock EFI system. This truck has 112,000 miles all with turbos, and it knocks on what they call "tip in" as throttle is depressed, before the computer senses the MAF is in the twilight zone compared to what is normal. This one second rattle is annoying, but harmless in eight years. With 100 unleaded, there is no audible knock at all. Some octane boosters have been tried with no success. I even tried some name brand stuff that's supposed to make "race gas" out of pump gas. You'd think I knew better, but this was a free sample for testing by Terry Paine. A quart to five gallons did nothing, two quarts to five gallons did nothing but make us laugh.
Leaded race gas or 100LL Av gas is in my opinion the only reliable octane booster for pump gas. On a few occasions I get to ride a 1000 HTG triple "pump gas" engine with 200-225 HP depending on whether power jets are set for .70 or .57. I like to use 100LL Av because it's cheap and always fresh and good enough. And I can water it down as I go and still have fun until dilution makes me afraid. Then I just cool it or give 1/2 turn to the pj's. I respect that thing and get great, reliable enjoyment from it. People who run high HP on the trail need to respect their engines, and expect to be running 87 octane on occasion. So that means tuning for 87 if you must run 100% pump gas. That means running enough fuel, with relaxed timing if necessary to get you around .70 lb/hphr for hot rod two-strokes. And, it means you must have a cooling system that will keep up with your HP/ riding style. How can a Firecat cooling system designed for 130 HP be expected to keep up with a 170 HP big bore if you ride like a madman? Coolant temp should be monitored, and when engine coolant gets to be much over 120 degrees F (like you might experience on hard packed roads or lakes) you must take it easy or risk deto since hot engines are most likely to detonate.
Rejetting for doing lake runs can be a nuisance, so I like those adjustable power jets like used on Lectron carbs. A quick 1/4 or half turn twist can take you from .70 to .60 with a similar bump in HP when you know you have sufficient octane. I have limited experience with Holtzman float bowl pressure tuners, but I like what I've seen for ease of adjusting fuel flow. EFI owners love Boondocker EFI controllers, since you can have one map dyno programmed "up nord style" for mystery gas, and one for short blasts on what you know is decent octane gas. And maybe another for race gas dragracing. Just a click of the Boondocker and you go from race to ultra safe. Couldn't be better.
Kevin Cameron has devoted lots of time providing technical information on detonation in the DynoTechResearch archives. Understanding what we're buying at the pump, and understanding the causes and effects of deto is important if we expect to avoid it while having reasonable fun with our sleds. This most recent realization that we're being "hosed" at the pump should make us all afraid.
i got this from dyno-tech. Read it & weep!!!!
Polaris and Bombardier are using detonation sensing technology on some of their engines to help alert us while riding or dyno testing, and to try to protect sled owners who experience detonation on their engines. They utilize engine noise pickups bolted to the cylinder head surface and some computer tries to recognize some new loud vibration as possible deto, and adds fuel and/ or retards timing to reduce combustion chamber temperature. Lower temperature (and reduced HP) should eliminate the detonation and all is well.
Bombardier is smart, and has programmed their newest computers to recognize and remember detonation, even to the point of going into a permanent, dealer-only removable fail-safe mode if severe engine knock occurs. This way they might have the option of avoiding responsibility if the owner of a new XP800R detos a piston/ cylinder on 75 octane gas unknowingly used by the sled owner.
75 octane?
I use that low octane rating rating as an example since 75 was the lowest octane test result done by Dateline NBC on 85 samples of "name brand" high test gasoline purchased in California. In that sample group, 11 were substandard, well below the octane posted on the pump.
Since then there have been more eye-opening reports of octane fraud at the pump. Car and Driver magazine reports that of 2816 samples of "high test" gasoline tested the previous year in Michigan by the Bureau of Weights and Measures, 217 failed because of "low octane". Just last week the Today Show did a segment on NY State gasoline cheating, stating that 85% of gasoline tested this winter in NY was substandard. Roll the dice.
Digesting that information, we can assume that 10% of the time, when we fill our sleds with high test, we get boned with 87 or worse. This is no problem for most stock sleds which have safe BSFC and excellent cooling systems. But some high performance stockers that have marginal cooling systems (to save weight and cost) seem to be susceptible to detonation. My opinion is that the new Arctic Cats which have "reverse cooling" (heads get the cold water first like modern automotive performance street and race engines) are most resistant to detonation, and can run higher HP on pump gas than most others. I have no actual hard data, just feedback from many 100's of dyno users who run powerfully on the lakes and trails.
Now that we can enlist SkiDoo dealer Jim Cooper to monitor engine conditions during dyno testing SkiDoo engines, we see even light to moderate deto on his computer before things get bad (either going into "safe mode" or actually eroding a piston. We let Jim's deto meter go up to maybe half way before detuning. Richard Lavanant brought "93" octane gas from PA before doing stage tuning on his new XP800R. Bone stock with bone stock jetting Richard's engine made Jim Cooper's deto meter rattle hard to the right on his gasoline. Richard fulled a jug with 93 from the gas station near the dyno, and that detonation was gone.
This same problem occurred with an XP860R big bore tested on my dyno a few weeks ago. This anonymous owner brought five gallons of "93" from his uncle's gas station in Rochester, and that gas pegged Jim Cooper's deto meter instantly with "safe" jetting! That problem also went away with gas from around the corner from the dyno. Now the uncle knew that his nephew was coming to dyno his sled, and I would think that if he was knowingly selling 87 for 93 he would have suggested that his nephew use different gas. In that case I'm betting that the gas wholesaler could be the culprit. Think of the extra $ people make for selling 87 as 93! How about the bar on the trail with above ground tank with "93" written in Magic Marker on the pump?
I get calls/ emails too often from people who have tuned closely for max "93" performance, wondering about mysterious, sudden detonation after many miles of dandiness. Always, something has differed from those good times. Leaner mixture? Hotter engine? Longer time at WOT? Usually it's the gas.
So what are we to do? The deto protection on Polaris' and SkiDoos is better than nothing, but not perfect. Extended periods of light occasional detonation, seemingly deemed acceptable by the sleds' computer, can gradually overheat pistons as the random "hits" of deto scour away the cooling boundary of air protecting the aluminum pistons (1200 degree melting point) from the 5000 degree flame. Pistons grow and sieze on "four corners", or actually melt just before they seize, because of the loss of that cooling boundary of air. New piston, new nickasil, all because some greedy wholesaler or retailer wanted to pocket an extra $2 per sled tankful.
So what can we do? Octane boosters so far have proven useless to me. My own motor octane tester is a 2000 Silverado 5.3 with twin GT25 Garrett turbos and completely stock EFI system. This truck has 112,000 miles all with turbos, and it knocks on what they call "tip in" as throttle is depressed, before the computer senses the MAF is in the twilight zone compared to what is normal. This one second rattle is annoying, but harmless in eight years. With 100 unleaded, there is no audible knock at all. Some octane boosters have been tried with no success. I even tried some name brand stuff that's supposed to make "race gas" out of pump gas. You'd think I knew better, but this was a free sample for testing by Terry Paine. A quart to five gallons did nothing, two quarts to five gallons did nothing but make us laugh.
Leaded race gas or 100LL Av gas is in my opinion the only reliable octane booster for pump gas. On a few occasions I get to ride a 1000 HTG triple "pump gas" engine with 200-225 HP depending on whether power jets are set for .70 or .57. I like to use 100LL Av because it's cheap and always fresh and good enough. And I can water it down as I go and still have fun until dilution makes me afraid. Then I just cool it or give 1/2 turn to the pj's. I respect that thing and get great, reliable enjoyment from it. People who run high HP on the trail need to respect their engines, and expect to be running 87 octane on occasion. So that means tuning for 87 if you must run 100% pump gas. That means running enough fuel, with relaxed timing if necessary to get you around .70 lb/hphr for hot rod two-strokes. And, it means you must have a cooling system that will keep up with your HP/ riding style. How can a Firecat cooling system designed for 130 HP be expected to keep up with a 170 HP big bore if you ride like a madman? Coolant temp should be monitored, and when engine coolant gets to be much over 120 degrees F (like you might experience on hard packed roads or lakes) you must take it easy or risk deto since hot engines are most likely to detonate.
Rejetting for doing lake runs can be a nuisance, so I like those adjustable power jets like used on Lectron carbs. A quick 1/4 or half turn twist can take you from .70 to .60 with a similar bump in HP when you know you have sufficient octane. I have limited experience with Holtzman float bowl pressure tuners, but I like what I've seen for ease of adjusting fuel flow. EFI owners love Boondocker EFI controllers, since you can have one map dyno programmed "up nord style" for mystery gas, and one for short blasts on what you know is decent octane gas. And maybe another for race gas dragracing. Just a click of the Boondocker and you go from race to ultra safe. Couldn't be better.
Kevin Cameron has devoted lots of time providing technical information on detonation in the DynoTechResearch archives. Understanding what we're buying at the pump, and understanding the causes and effects of deto is important if we expect to avoid it while having reasonable fun with our sleds. This most recent realization that we're being "hosed" at the pump should make us all afraid.
daman
New member
yup already posted(link) good read...
Old gas is always a big concern for me when I pull into a station to fill up the SRX as I've had too many burn downs and want to avoid any more especially from old gas.The only thing I have going for me where I live is the fact that aquaculture farming (salmon) is a large part of the local economy and as such a couple of the area gas stations,hopefully,go through a fair bit of supreme gas where it's used in the outboard engines and other equipment.Is it a big job to test for octane in gas?Supposing I wanted to get a sample done to see just how fresh it might be.
PhatboyC
New member
Good read.
Yeah a Octane testing kit would be great.
This is one of the reason I only buy TopTier gas. Has nothing to do with the octane level but it makes sure you have enough detergent in the gas to keep the engine clean. Which is the other half of the battle...
http://www.toptiergas.com/
Yeah a Octane testing kit would be great.
This is one of the reason I only buy TopTier gas. Has nothing to do with the octane level but it makes sure you have enough detergent in the gas to keep the engine clean. Which is the other half of the battle...
http://www.toptiergas.com/
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horkn
New member
it is a good read, and I always liked the fact that my XC retards timing, and saves the engine if it gets too hot. I don't have the detonation sensor on mine, but I have seen those work really well.
which is another reason I use 87 on almost all the time. 87 octane is always used and is the freshest at gas stations, but mid and premiums gas can get really old since most people don't need it.
which is another reason I use 87 on almost all the time. 87 octane is always used and is the freshest at gas stations, but mid and premiums gas can get really old since most people don't need it.
VenomMod
New member
I work at a gas station while at school here in Houghton and I can tell you that I wouldn't buy gas at my place of work. It's not that we don't go through enough gas, we really go through a lot, but quality lacks. I usually will go out of my way to go up town and buy some Shell V-Power Premium. Not only does my sled run better, but my new Silverado likes it better. It's ashame that people like to rip off others that buy their product. Especially when the circumstances are toys that break. I'm fortunate enough to not have had a sled burn down up here, but the lack in quality has kept me from doing motor work done, in fear of a burn down. It's pretty sad when you think about it. But people see $$ in their eyes and will do anything to get it.
taylzee
New member
What about mixing a little candy (C12) or even 111 in. If 93 was 93 then it would be a waste but to me it is cheap insurance and man do they run smooth on a 10:1 mix.
Buy shell premium.....never ever had a problem; even running it at 12 pounds boost(240 hp) in my RX-1 Turbo.
daman
New member
93???Turk said:
it is 91 but it,s an honest real world 91.
Not all of us have a shell gas station nearby. And after reading this to slow the amount of detonations just keep the sled cooler? And sometimes just running 87 is better than running 91? Just asking these cause our Viper's seem to have the DCS come on a lot around here at about 7000rpm.
taylzee
New member
We Canucks have some stations that will tell ya that the Supreme or ultra premium is 93 Octane.
akrievins
New member
Sunoco out here in Ontario has 94 octane according to the pumps!
fastmax
New member
Turk is correct, Shell fuel is always fresh and shipped to the pumps in western Canada within 14 days or less after being refined from crude oil. It is part of thier "corporate image"
YAMAHIZAL700
New member
Very informative read. Ive always wonder how you really know if your getting primium or if its really 87 labeled 93. I wonder if there is any truck drivers that deliver gas. You would thinks they would know if the gas stations are goofing us, since they know what tanks it gets pumped into.
daman
New member
Yes that helps allot, that and no LONG WOT pulls..SXlover said:
Really enjoyed and learned from your write up. Thanks!
PZ 1
Member
- Joined
- Mar 12, 2005
- Messages
- 987
fourbarrel said:
Special equipment is required to do octane testing, unless the methods have recently changed. I would think that most states take samples at the pumps and do testing. That is not always a good test though as this article shows:
http://www.jsonline.com/story/index.aspx?id=317524
I was told that a recommendation for buying fuel is to get it at a company owned station. That way you should get that companies gas of the proper quality. That may be hard to do though, in the area of Wisconsin where I live, all the stations are independantly owned. If the oil company that franchises the station does not do a good job of policing thier stations, the owner of the station can buy any grade of fuel from any company he wants.
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tripplec
New member
Hmmm Is running a high octane gasoline bad for the sled? I was considering running at tank or part of the Shell Premium 91 Octane as I recall. They have excellent detergent additive in that grade and though it would help clean out the fuel and engine chambers as it does in cars. Not on a regular basis (too expensive) but once a season.
My Venture does not have a guage but likely an overheat light. But like auto idiot lights in cars. It the engine about dead when it comes on?
My Venture does not have a guage but likely an overheat light. But like auto idiot lights in cars. It the engine about dead when it comes on?