R
count me out of this thread guys...cant read past page 2
Polaris Engine and surrounding information
- Thread starter RKT
- Start date
So all these posts of you talking that you know all this stuff about this engine and you don't even know the flow of coolant. Go back under your rock.
H
Good reading on a sunday.
I think it is clear for the avreage reader that combustion temp is way higher then the coolant, and i dont see the link. It does not affect the cold shock. Seems like someone try to mislead to belive coolant is taking care of all the heat. Most of combustion heat goes out with the exhaust.
Why does the engine have a thermostat at all, if consistent water temp is not needed?
To those that a change in temp like this not affect anything, think again.
Aluminium react alot more to temp changes than steel, still you only need 50-60 celcius temp diffrence to make a bearing slip onto a shaft, that would be a press fit on equal temp.
If you get a 20c temp diff between case and monoblock, this could make the case put force on cylinder skirt, if skirt are a tight fit into case.
Water enter the case before going up sylinder. Since heat source is at top, bottom part of engine will cool down before the monoblock.
And why is it that this crakcs in the skirt seems to be less present on turbosleds then on na sleds?
Is that because turboguys are more aware of the heat, and let their engines idle more before shutdown to cool down their turbos?
Sent from my LT25i using Tapatalk 2
I think it is clear for the avreage reader that combustion temp is way higher then the coolant, and i dont see the link. It does not affect the cold shock. Seems like someone try to mislead to belive coolant is taking care of all the heat. Most of combustion heat goes out with the exhaust.
Why does the engine have a thermostat at all, if consistent water temp is not needed?
To those that a change in temp like this not affect anything, think again.
Aluminium react alot more to temp changes than steel, still you only need 50-60 celcius temp diffrence to make a bearing slip onto a shaft, that would be a press fit on equal temp.
If you get a 20c temp diff between case and monoblock, this could make the case put force on cylinder skirt, if skirt are a tight fit into case.
Water enter the case before going up sylinder. Since heat source is at top, bottom part of engine will cool down before the monoblock.
And why is it that this crakcs in the skirt seems to be less present on turbosleds then on na sleds?
Is that because turboguys are more aware of the heat, and let their engines idle more before shutdown to cool down their turbos?
Sent from my LT25i using Tapatalk 2
First guy I've heard mention idling an engine for a few minutes to stabilize water/engine temp before shutdown. When I was taught to run equipment that was hammered into you over and over again. ALWAYS idle the engine before shutdown. Great post Daltech
R
This is true.
The main reason you were taught to cool an equipment motor off was because of the turbo. You didn't want the turbo to be so hot that it would cook the oil. You had to keep the oil flowing through the turbo until the temp dropped down. However there are other reasons for cooling the motor down. A motor (especially a sled motor) lives a terrible existence. The more that a rider can do to lessen the hardships, the longer the motor will live. Fact not myth.
O
Above #1- #4. I guess there's no dispute on those issues. There is other members on here that would dispute some of the info, but they haven't been baited into this thread.
#5-- There is a couple kits selling a ship, which basically claims the volume is lacking since they are seeing pretty big gains by increasing volume.
Some have taken a somewhat worn engine and compared it to a fresh engine with kit. Hard science. ?? Probably not. But real life gains, Yes. Since most of our engines are beyond the 2,000 mile mark now, those gains would be great.
#6-- I've read the 10 & 11's didnt have the temp pull power.
I've read that the 12 & 13's do pull power above 129 degrees.
I guess someone could dyno a cold motor vs a hot motor. Then we would know.
Other than that, its just seat of the pants feel. Which can be pretty accurate.
Personally, I can tell you that my sled seems to lay down when temp get near 140.
No hard data, just feeling the difference in charastics at 120 degrees, and above 140 or so.
I have 3,000 miles on mine, so i would like to think that i know how it feels from day to day.
I definately feel its worth modifying the cooling system to keep temps in the 115 range. And thats exactly what i plan to do.
#5-- There is a couple kits selling a ship, which basically claims the volume is lacking since they are seeing pretty big gains by increasing volume.
Some have taken a somewhat worn engine and compared it to a fresh engine with kit. Hard science. ?? Probably not. But real life gains, Yes. Since most of our engines are beyond the 2,000 mile mark now, those gains would be great.
#6-- I've read the 10 & 11's didnt have the temp pull power.
I've read that the 12 & 13's do pull power above 129 degrees.
I guess someone could dyno a cold motor vs a hot motor. Then we would know.
Other than that, its just seat of the pants feel. Which can be pretty accurate.
Personally, I can tell you that my sled seems to lay down when temp get near 140.
No hard data, just feeling the difference in charastics at 120 degrees, and above 140 or so.
I have 3,000 miles on mine, so i would like to think that i know how it feels from day to day.
I definately feel its worth modifying the cooling system to keep temps in the 115 range. And thats exactly what i plan to do.
I will comment on rod ratio...there is no perfect rod ratio(just like there is no perfect compression ratio)but with that said, there are generalities that can be made to different rod ratios..First and foremost, the longer the rod ratio for a given stroke,the less physical load the piston and cylinder see(this has been proven since the beginning of internal combustion engines). the shorter the ratio the more loads the piston and cylinder see...these are facts..beyond any dispute any where but here....next there is no denying that the poo motor is significatently smaller and lighter then the competition, again fact.the less rigid a engine is(particularly in case/cylinder/crank/head) the less reliable it will be at the same power output(if it even lives long enough to make that power level). combine those two as they are in the pro..and you end up with a motor that is less reliable then the competition while making less power..heres another simple fact from the racing world..you will never ever hear of a engine builder shorting rod ratio ......and in fact has become standard fare to lengthen rod ratio in most aplications(especially in engines running over 8000 rpm). short of building a stiffer cylinder wall and/or lengthing the rod ratio, everything else is
but a short term patch(compared to stiffer cylinder wall/longer rod)..On the pro to make it more reliable while making more power then the competition the best method would be a new cylinder with more /better material and a longer rod ratio.
R
Nobody is disputing that a longer rod will lessen loading.. The question, at hand, IS.."Is the rod ratio of the CFI poor?" Very simple question.
OK, so using that reasoning.. Both Cat and Doo would benefit greatly from a longer rod?
The FACT is....Polaris has a BETTER rod ratio than either Cat or Doo..
So, based on that fact,,,this would tell you that the Polaris Rod Ratio is not poor.
Racing fact for you--> in the 2 stroke world (which is what we are in with this engine) many builders will shorten the rod in order to improve engine power.. Some also lengthen the rod for the same reason.. it all depends on the engine and its application...
4 stroke theory does not always apply to the 2 stroke world... in fact, SELDOM do apply..
What short term patch, as you call it are we talking about? Please show your data to support the "short termness" of these patches?
Also, please show the data to support the LONG term effectiveness of the long rod conversion? I guess you have one and can supply some information?
Please No speculation...based on theory in the 4 stroke world.. But hard data to show the longer rod CFI 800 engine out lasting the (stock)shorter rod engine.
As far as the engine making the same or more power than its competition.. VERY easily done via engine modifications.. We own all 3 brands.. No doubt which ones make the most power in stock and/or mod form..
Let's consider the Turbo'd CFI 800
The turbo'd CFI 800 makes some good power and seems to hold up pretty well (surprisingly) considering the weak cylinder, out of round bore, and poor rod ratio...
G
'Bin here before. So, maybe we should define the terms "cold hard facts" or "data" first.
Without that definition this discussion will lead to nothing again.
For me data or facts are supported by numbers and-or measurements. If the OPINION of two people is enough to be considered data (I'm referring to the temp point at which the engine losses power) then this is another waste-of-space thread that seems to have a lot of similarities to past threads that were in fact turned into bashing threads between two engine builders (it seems this one had a very leading start too, very specific questions).
If on snow experience form one person is in fact data, my '13 starts to lose power at around 130. My crank mounted dyno (the clutches) tell me so. Keep it below that number and rpm and track speed doesn't drop. Let it go above and rpm and track speed drops. If you never load your motor for torque you will never see the difference but, you will never achieve the max acceleration of your track that is possible.
Easy fix though (thanks TRS) and it provides a by-pass to help stabilize engine temps quicker. Two birds with one stone (if you believe the data LOL). Cold hard data to me would be dyno # at 120 degrees and same place dyno # at 135. I haven't got that data but I'm happy with the changes it did for me.
Cold shot, don't know what that means to you but in this instance to me, it means a quick influx of coolant into the cylinders and head upon start up of a heat soaked (from sitting) motor.
Everyone agrees that the motor begins to build heat in the combustion chamber again as soon as it starts running. Everyone agrees that this combustion heat further expands the already expanded piston as the combustion heat is transferred into the piston crown and down the piston. Everyone agrees that the cylinder will contract if it is cooled (heat drawn away by the cooler coolant coming in from the heat exchangers). Everyone agrees that this will create a tolerance issue (expanded piston, contracted cylinder).
What the question seems to be is if this is the cause (or one of the causes) of piston failure in the Pro motor.
I have not seen data to confirm this or un-confirm this. But,,, I`m saying if you think this is not a real world situation and a real possibility in any motor in cold climate use, then I wish you luck with whoevers motor you own.
I learned it the hard way back with my first bike (69 CZ250 lol). Snow riding and no warm ups equals sandpaper and oil on the kitchen table (boy my mom was mad lol). I also have seen it 100's and 100's of times when I worked on toys for boys and tools for professionals.
So why don't we just agree that it is a possible to do severe damage to a motor if the temps have not stabilized before you load the motor with the CVT. Does it not make sense (common)? Every 800 out today has protection against this (either coolant flow direction or engine management) except the Pro. That's a data fact that is too coincidental for me.
So now we have 6 "myths" to dispute or prove with data (if we can define data lol).
1; Rod ratio change needed? Is it bad to have a better rod ratio? Will a better rod ratio reduce the thrust loads on the piston.
2; Cold shot thing? Wow. I can't believe this is being argued. Besides the cylinder piston fit stuff you have to think of crankcase maybe too. I'm waiting for data to prove to me the Pro doesn't need to worry about this like other motors do.
3; Cylinder sizing from the factory? I've seen issues here from every manufacturer since forever lol. The sizing for max power is not the same as sizing "for the masses". Why? #2 is why and one thing not on this list of "myths", being able to get rid of the heat created at extended periods of full power (something that stock clutching takes care of).
4; Offset of cylinders. If Pol. has officially announced that there is no offset maybe we could get a link to this and put it to bed. But, like I said before no one has shown me properly (videos included) if or if not this is fact. You need 3 points of reference along the line to do this.
5; (oh boy more "myths" lol) Crankcase volume. There isn't many people in the world that can provide data on this point. Asking for that (to someone in the know) is just a case of asking for a debate.
If you think you know how to figure out this ratio you should know that subtle changes make huge gains but only in a specific rpm range (without changing secondary compression too, then you need to factor in the added heat losses you create from the added pressures and whether your motor and cooling system can handle it to actually give you usable everyday power increase).
With a torque designed motor (twins) changing the primary to secondary compression ratio will not have as much effect on the HP as the change in port duration you get from the spacer plate.
Bottom line for improving power is whether or not you can get rid of the heat and make it usable everyday. (Pro problem?? Poo design??)
6; Engine temp at which Poo decided to start limiting power to self protect. MO or "data" covered above. But I would like to add, with the warranty history these motors had previously in the Dragons, I can see the self protect programming (temp related timing retard, like mine, and fuel delivery increase, like mine) to err on the safe side for the warranty departments input.
If your a** can't feel that point it ain't as good as my a** lol.
Without that definition this discussion will lead to nothing again.
For me data or facts are supported by numbers and-or measurements. If the OPINION of two people is enough to be considered data (I'm referring to the temp point at which the engine losses power) then this is another waste-of-space thread that seems to have a lot of similarities to past threads that were in fact turned into bashing threads between two engine builders (it seems this one had a very leading start too, very specific questions).
If on snow experience form one person is in fact data, my '13 starts to lose power at around 130. My crank mounted dyno (the clutches) tell me so. Keep it below that number and rpm and track speed doesn't drop. Let it go above and rpm and track speed drops. If you never load your motor for torque you will never see the difference but, you will never achieve the max acceleration of your track that is possible.
Easy fix though (thanks TRS) and it provides a by-pass to help stabilize engine temps quicker. Two birds with one stone (if you believe the data LOL). Cold hard data to me would be dyno # at 120 degrees and same place dyno # at 135. I haven't got that data but I'm happy with the changes it did for me.
Cold shot, don't know what that means to you but in this instance to me, it means a quick influx of coolant into the cylinders and head upon start up of a heat soaked (from sitting) motor.
Everyone agrees that the motor begins to build heat in the combustion chamber again as soon as it starts running. Everyone agrees that this combustion heat further expands the already expanded piston as the combustion heat is transferred into the piston crown and down the piston. Everyone agrees that the cylinder will contract if it is cooled (heat drawn away by the cooler coolant coming in from the heat exchangers). Everyone agrees that this will create a tolerance issue (expanded piston, contracted cylinder).
What the question seems to be is if this is the cause (or one of the causes) of piston failure in the Pro motor.
I have not seen data to confirm this or un-confirm this. But,,, I`m saying if you think this is not a real world situation and a real possibility in any motor in cold climate use, then I wish you luck with whoevers motor you own.
I learned it the hard way back with my first bike (69 CZ250 lol). Snow riding and no warm ups equals sandpaper and oil on the kitchen table (boy my mom was mad lol). I also have seen it 100's and 100's of times when I worked on toys for boys and tools for professionals.
So why don't we just agree that it is a possible to do severe damage to a motor if the temps have not stabilized before you load the motor with the CVT. Does it not make sense (common)? Every 800 out today has protection against this (either coolant flow direction or engine management) except the Pro. That's a data fact that is too coincidental for me.
So now we have 6 "myths" to dispute or prove with data (if we can define data lol).
1; Rod ratio change needed? Is it bad to have a better rod ratio? Will a better rod ratio reduce the thrust loads on the piston.
2; Cold shot thing? Wow. I can't believe this is being argued. Besides the cylinder piston fit stuff you have to think of crankcase maybe too. I'm waiting for data to prove to me the Pro doesn't need to worry about this like other motors do.
3; Cylinder sizing from the factory? I've seen issues here from every manufacturer since forever lol. The sizing for max power is not the same as sizing "for the masses". Why? #2 is why and one thing not on this list of "myths", being able to get rid of the heat created at extended periods of full power (something that stock clutching takes care of).
4; Offset of cylinders. If Pol. has officially announced that there is no offset maybe we could get a link to this and put it to bed. But, like I said before no one has shown me properly (videos included) if or if not this is fact. You need 3 points of reference along the line to do this.
5; (oh boy more "myths" lol) Crankcase volume. There isn't many people in the world that can provide data on this point. Asking for that (to someone in the know) is just a case of asking for a debate.
If you think you know how to figure out this ratio you should know that subtle changes make huge gains but only in a specific rpm range (without changing secondary compression too, then you need to factor in the added heat losses you create from the added pressures and whether your motor and cooling system can handle it to actually give you usable everyday power increase).
With a torque designed motor (twins) changing the primary to secondary compression ratio will not have as much effect on the HP as the change in port duration you get from the spacer plate.
Bottom line for improving power is whether or not you can get rid of the heat and make it usable everyday. (Pro problem?? Poo design??)
6; Engine temp at which Poo decided to start limiting power to self protect. MO or "data" covered above. But I would like to add, with the warranty history these motors had previously in the Dragons, I can see the self protect programming (temp related timing retard, like mine, and fuel delivery increase, like mine) to err on the safe side for the warranty departments input.
If your a** can't feel that point it ain't as good as my a** lol.
9
I bought a 2010 Dragon from a buddy of mine in 2012. He was moving so the price was right. It ran fine when we rode together so I thought it must be OK despite what I was reading . "that stuff won't happen to me...."right? Well ,500 miles after I bought it, lost the voltage regulator no surprise here right. Took it to the dealer 3 hours of labor to figure that out plus the cost of the regulator. Got it back and it would run but the check engine light came on everytime at 6,000 rpm and put me in limp mode, another trip shot. Back to the dealer and they pulled the top end off and guess what, the exhaust side of the jugs had the Nikilsil worn off with deep gouges in the piston. They wanted $2400 to rebuild back to stock, no thanks. I read somewhere on here about the "fix kit" for these motors and found 1 on e-bay for $425 with shipping. This kit had Wisco pistons which I heard they run a little tighter. Put this kit in , rebuilt monoblock etc. and I could not beileve how much quieter this motor ran. Put 500 miles on it since and it seams to be holding together. I replaced the TPS while I had the motor out since I think that was the root cause of it going into limp mode @ 6,000 rpm. I am thinking about scoping the cylinders before I start the season. A local shop warned me to get the engine as close to 120 before putting the hammer down especially with the tighter pistons. Wish me luck!!
R
Kelsey, rod ratio is a tool just like compression ratio, bore /stroke ratio and for any given design there is an optimal ratio. what any other motor runs for a rod ratio is irrelevant when compared to what this specific motor has and needs based on the design of this motor(compact/lightweight). Heres another way to look at the load the cylinder is seeing based solely on this particular engine family, neither the stock 600 or 700 built on this same platform has an issue with taking out either pistons or cylinders, yet the 800 does. Why? Why would this same family of motors all live long happy lives until they enlarge to 800cc? what changes? pistons for all 3 displacements are all from the same manufacturer, all built to the same general specs, yet only the largest displacement has issues, same with the cylinders/cases/cranks/rods/heads, all built from the same materials to the same general dimensions(other then stroke/bore for displacement), yet only the 8 has issues(yes they all blow up once in a while but its not common with the smaller 2 like it is with the 8)...
As for questioning my ability on 2 stroke engines..whatever floats your boat, oddly some of the best aftermarket Polaris engine guys( Indy Dan, Brad at PAR) seem to hold the same thought I do that lengthening the rod is a better fix on this 800 poo. I am sorry I don't hold your opinion in awe..it just dosent jive with what my own experiences have shown, but as I have said before, good luck and I hope all that do use your stuff have great results with it...
As for questioning my ability on 2 stroke engines..whatever floats your boat, oddly some of the best aftermarket Polaris engine guys( Indy Dan, Brad at PAR) seem to hold the same thought I do that lengthening the rod is a better fix on this 800 poo. I am sorry I don't hold your opinion in awe..it just dosent jive with what my own experiences have shown, but as I have said before, good luck and I hope all that do use your stuff have great results with it...
Is this for real??
It sure is. Almost as good as the Cat fight in the 1100T section.
Afraid so. Everybody IS edgy, waiting for snow. Everybody is NOT to busy working.
Some of us even have the time to create and sustain a 5 part, no wait, make that a 6 part argument about one particular engine that they sell hop-up parts for.
If this was after the first year with the engine, ok, but this has been argued about for 3+ years now. Talk about :deadhorse:
R
Ya, I know it is horrible when somebody uses their FREE time to HELP people understand their engine ... Terrible, Terrible thing....
R
Yup, I see you trying to find some hidden meaning and hidden agenda in everything I write.. INSTEAD of taking things at FACE VALUE like most do.... Been seeing it for years now.....
