count me out of this thread guys...cant read past page 2
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ok...i have a question...does the water enter the top of the cylinders...and then fall down to the front of the water pump...or does it get pushed up from the bottom and reach the top?
I have to ask, are people here saying that it is okay to just ignore warm up and stabilizing engine temps after a short shutdown on a liquid cooled motor in winter conditions?
If you are, shame on you for giving bad advise to the readers.
Engines clearances are stable and correct at operating temps. That is designed in for proper engine management (EPA) and engine life (warranty). Comparing a 1000 lb motor to a 100 lb motor is just silly unless you are trying to mislead or do not understand the difference in expansion between a thin piece of aluminum and a thick piece of cast iron.
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In no way was I implying that you should not give your coolant temp time to stabilize before taking off full throttle after stopping for a few min. If I agree with the idea of cold shot or not makes no difference. I always let my sled run to the proper operating temp before I move (My Father taught me that when I was six haha.) Nor was I trying to compare expansion rates between aluminum and cast I was just agreeing with the fact that your engine will remain hotter than your coolant and the heat will continue to travel throughout your system until the entire system is the same temp, while giving an example of a system that works the same way that I can monitor a lot more temperature variables constantly through a shutdown, cool down, and start up. (Also in winter or summer conditions.) I would give my "opinion" on how much I think the small amount of coolant pumping up through the engine cools the block or cylinders on a start up after a few min but I have no ability to monitor it so it would only be my "opinion".
I have to ask, are people here saying that it is okay to just ignore warm up and stabilizing engine temps after a short shutdown on a liquid cooled motor in winter conditions?
If you are, shame on you for giving bad advise to the readers.
Engines clearances are stable and correct at operating temps. That is designed in for proper engine management (EPA) and engine life (warranty). Comparing a 1000 lb motor to a 100 lb motor is just silly unless you are trying to mislead or do not understand the difference in expansion between a thin piece of aluminum and a thick piece of cast iron.
QUOTE]
In no way was I implying that you should not give your coolant temp time to stabilize before taking off full throttle after stopping for a few min. If I agree with the idea of cold shot or not makes no difference. I always let my sled run to the proper operating temp before I move (My Father taught me that when I was six haha.) Nor was I trying to compare expansion rates between aluminum and cast I was just agreeing with the fact that your engine will remain hotter than your coolant and the heat will continue to travel throughout your system until the entire system is the same temp, while giving an example of a system that works the same way that I can monitor a lot more temperature variables constantly through a shutdown, cool down, and start up. (Also in winter or summer conditions.) I would give my "opinion" on how much I think the small amount of coolant pumping up through the engine cools the block or cylinders on a start up after a few min but I have no ability to monitor it so it would only be my "opinion".
Hogan.. Thanks for keeping the thread TRUE to the topic..
We are looking for FACTS!---> REAL HARD DATA that supports or debunks the "claims" that were listed in Post #1 and subsequent posts.
Nobody is disputng that metal objects expand and contract with a temperature change... This is FACT and has been proven over a milennia ago..
What we ARE looking for is how much is the Polaris Cylinder and Piston changing when on the snow?
Up to this point.. we have zero data for this.
Let's continue down the list:
1)Rod Ratio is lacking?--> So far, zero data to support this claim. Hard data was provided to support that the rod ratio was well in the desired range and better than any other 800 class modern sled. Still looking for data to show otherwise.
2)Cold Shot that is causing engine failure:-->Hogan has provided(thanks) some good hard data on cylinder temps with coolant changes on another engine that is 100% surrounded by coolant (where the CFI has VERY little of the cylinder wall that is in contact with ANY coolant.. very little).
Other hard data would be the near zero ( I say near zero because I have no data to say if there has even been any--> but I know of zero) engine failures that have been attributed to any "cold shot" happening...
Anybody have anything to show otherwise?
Does anybody have any engine that has failed due to the cold shot phenom?
3)Cylinders are plated too large and not round from the factory--> Information was provided to show a large number has been measured and all in spec.. Couple that with gross error and faulty equipment that would have to be present to have this be a reality.....
Again...No hard data to show any that were out of spec as delivered..
Anybody?
4) The cylinders are offset with respect to center-line of the crank.:
I have personally inspected this and Polaris Industries will also tell you that there is no offset..
But.. if there is data to support that it is offset.. please post it here.
Added later in the thread..
5) Crankcase volume is lacking: Nothing from anybody yet... has anybody measured this and calculated the primary compression?
6) When Coolant temps are above 132F the ECM pulls Power: Tinkerjohnson, myself, and some others have provided data to show this not to be the case. I think this maybe year dependent (but no data to support this).
I tested this by manually controlling what the ECM sees for coolant temp and was able to determine an upper temp range where power is lowered However; I could not find a lower range, which was odd IMO..tinker found about the same...
Side note: Testing has found that as long as the ECM is NOT unhappy with a lower temp.. the lower temp will always be better in terms of producing power..but you have to know when too low is too low and this varies with programming and sled manufacturers
This is true.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
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 isAbove #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.
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.
'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.
Couldn't agree more....
That is what we have is COLD HARD FACTS and Supporting DATA... on the Rod ratio, cylinder bore size vs. piston size, Piston skirt size after short and long term running AND crank offset (Taken from 4 points (1 better than you need LOL)
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.
Here is where I struggle a bit and maybe others do as well?? The engine is not heat soaked from sitting.. The engine is COOLING.. not heating... At no time will a sitting engine be hotter than when it was running.. Agreed?
So, the whole heat soaked terminology , I think, is a bit misleading
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).
Another area that is "grey"
On a 2 stroke engine..VERY little of the CYLINDER WALL (where the piston resides) is in ANY contact with the cooling system.. This is one point that I was trying to get across. This is NOT a 4 stroke engine that has a dedicated cooling system that surrounds the entire cylinder and head..
The 2 stroke also does not have an extra 2 strokes where the piston and cylinder can cool off...
The crankcase, on this engine, has very little contact with the coolant as well..
So, all this coolant contacting the cylinder is a bit misleading..Yes, it is contacting the cylinder at points.. but is not contacting the entire cylinder at the bore (piston area) where we are most concerned? Agreed?
What the question seems to be is if this is the cause (or one of the causes) of piston failure in the Pro motor.
What piston failures are you referencing?
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.
Yes, everybody should warm up their engine before a heavy load.. that is just smart riding..
I do not see where the Pro does not have any "protection" against this??
What does it not have? that the others do??
Keep in mind.. Reverse flow (CAT) is there to COOL the engine FASTER not slower. The coolant is colder when it hits the head with reverse flow vs. conventional flow..
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.
See above
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.
Really not hard to measure.. Maybe, just maybe.. I have performed this measurement
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.
Is this for real??
Is this for real??
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![]()
Ya, I know it is horrible when somebody uses their FREE time to HELP people understand their engine ... Terrible, Terrible thing....
I'm wondering... You don't even see it, do you??