BYPASS THERMOSTAT UPGRADE (PREVIOUSLY $28 upgrade)

[TRS]

Sorry for the rant. This will not fix a "no snow to the rear cooler riding issue". Lets help ourselves here. Fix it the old fashion way. Pack a mesh(18x24) onion, potato,or laundry bag with you. Pack two in case you lose one. Cheap,light weight, and only need it certain times of the year. When needed pack it full of snow and rubber snubber it to the (top) of your rear coolers. It may not look top of the line, but your riding.

 

[wfieldin]

It holds a nice 110- 116 in powder, but as TRS states this is not a fix for hard pack trail riding.

 

[TRS]

Operating temps seem to be very crucial on the CFI2. Here is an example, a 2013 PRO 155 800. I was clutching this sled. Long up hill pulls, long side hill pulls, tree riding(74 mi. day). At 125 to 127 degrees it would hold 8100 RPM and very responsive. When it hit 129 it would fall to 7900 RPM. At 131 it fell to 7600 which is below peak torque. At 7600 it could not and cannot recover and would drop to 7400. Get it back down to 125 and all was well again, hit 131 and you better be looking for an escape route. What is the ECU doing??? When running the sled down the trail, no load, wide open, and it hit 131 degrees it would drop 100-150 RPM. With a heavy load on the motor it is more evident on running issues.

 

[pus1100]

Operating temps seem to be very crucial on the CFI2. Here is an example, a 2013 PRO 155 800. I was clutching this sled. Long up hill pulls, long side hill pulls, tree riding(74 mi. day). At 125 to 127 degrees it would hold 8100 RPM and very responsive. When it hit 129 it would fall to 7900 RPM. At 131 it fell to 7600 which is below peak torque. At 7600 it could not and cannot recover and would drop to 7400. Get it back down to 125 and all was well again, hit 131 and you better be looking for an escape route. What is the ECU doing??? When running the sled down the trail, no load, wide open, and it hit 131 degrees it would drop 100-150 RPM. With a heavy load on the motor it is more evident on running issues.

bingo.had all those symptoms with my 2011 pro.my 2013 std rmk WITH frontcooler has steady 51-53 degree celsius operating temp,unless hardpack without scratchers down.it runs very consistent,clutching is spot on.ECU is doing exactly what the beancounters in the warranty department tells it to do,flood the engine with gas and maybe yank the timing a little.

 

[geo]

I don't think extra tunnel cooler would change my 13's (don't know anything about 11 and 12) temp spike.

I've watched my temp gauge since day one and even a stocker with too light a weight (meaning the clutch is not asking the motor to work very hard) hit's this spike. As TRS said it just starts to lose power at 129 and on up and it doesn't take long for a modified one to get there. 100 to 150' of good strong braap then it starts to sign off
One other thing happens here too. It doesn't make a difference if there is 6' of fresh or 6"! As soon as you back off and turn out you can glance at the temp and will see it drop. By the time you are straightened out and gravity takes effect the temp has dropped to 125 or 123 in a matter of seconds and it's all good again.
Coolers are doing their job but the coolant can't flow through the engine fast enough because of the restriction caused by the tiny (Doo one looks bigger) open thermostat IMO. 1" in at the pump and maybe 5/8" out at the top of the head. At full load on this light engine that's a big deal. At 3/4 throttle not so much.

I believe the majority of " not backshifting" and "won't pull more weight even with the added power" threads have a lot to do with this temp spike. I even think it is designed in so that the beancounters safety protocols can take effect more quickly.
I've pulled my plugs in the field and have seen the amount the timing retards at this temp. I'd guess at 2 to 4 degrees easy.

Thanx for the confirmation TRS and the cure. I can`t wait to reinstall the clutching my a** likes instead of the one my computor requires me to run. Your pick of thermostat makes it better than the others I looked into.
For open country riders with the long pulls, I think this is a big bang for the buck. Install and ask more from your motor with clutch load. It won't fall off now but be ready to give it some fuel in case the pipe temp sensor can't keep up.

800 pro. 130 some ponies on a dyno lol. If you've ridden one you wonder about that no.. If you do short pokes with 160 plus sleds you wonder about that no..
I think that by the time you get up to temp to do a pull on the dyno the engine is already retarding itself to give that no.. This is a strong motor from what my a** tells me.

 

[Rick!]

I like the doostat thing but I bet that the running issues are related to intake air temp and maybe even exhaust pipe temp. I don't dispute your findings but I ain't buyin' a 500rpm drop due to a 4* F change in coolant temp.

 

[TRS]

A 200 RPM loss at 129* started the process. Peak torque with a hot pipe is 7900. Drop below that and you are in the land of no return. Add to that motors, with miles on them, with lower comp. and the stock HD ex. springs take over and the valves close. More Rpm loss. Now the TPS tells the ECU you are at full throttle but have not reached the RPM threshold to close the EV solenoid. Everything is headed south until you back out of the throttle and get back into it.

 

[pus1100]

Geo and TRS,in Realbass's push turbo thread there is a screenshot of his Vipec log.you can clearly see temp spikes related to tps/load,rpm and so on.i guess you can 'see' thermostat opening cycles in that log.

 

[Andreas83]

Great thread.
I am using this idea for my iqr 1200 build.

 

[snobyrd]

All I can say is WOW, I did this mod to my 13 pro with a rk drop in kit, and I was having powerloss issues at high rpms, my temps now are 115-120, and my sled can now pull 64 weights and hold revs at 81-8200. The funny thing that happened today though, most of my head bolts started leaking coolant, not sure why.
Myself and other members have been chasing our tails with low rs or " backshift " issues and I think the high coolant temps was the culprit.

 

[ditch1000]

All I can say is WOW, I did this mod to my 13 pro with a rk drop in kit, and I was having powerloss issues at high rpms, my temps now are 115-120, and my sled can now pull 64 weights and hold revs at 81-8200. The funny thing that happened today though, most of my head bolts started leaking coolant, not sure why.
Myself and other members have been chasing our tails with low rs or " backshift " issues and I think the high coolant temps was the culprit.

Guess I'm doing it this week. I'm seeing the same rpm drops as you were. I have all the parts togther and will get it ready for next weekend.

 

[geo]

Believe and just do it. Be ready to add some weight.

My stock thermostat opened up 100 thou at 140 degrees and 150 thou at 180 degrees.

Defective or by design ????

 

[ditch1000]

Believe and just do it. Be ready to add some weight.

My stock thermostat opened up 100 thou at 140 degrees and 150 thou at 180 degrees.

Defective or by design ????

Once the heat soak is gone the kit should make the power that it's promised. Is that what you guys are seeing?? When I had mine loaded last week, when the motor would heat up (even in 2 1/2' of fresh powder) the power would fall off.
Can't wait to try it again this weekend with the new coolant bypass in place.

 

[ak]

Go to the bottom of this page.http://floatingqrs.com/

Some one needs to build a resistor like this for polaris. They work good on the ski doos.

 

[TRS]

Once the heat soak is gone the kit should make the power that it's promised. Is that what you guys are seeing?? When I had mine loaded last week, when the motor would heat up (even in 2 1/2' of fresh powder) the power would fall off.
Can't wait to try it again this weekend with the new coolant bypass in place.

Lets not get this thread into something that it was not intended to be. I didn't claim or promise any HP gain. I was witnessing temp issues I thought could be addressed in a cheap, simple manner. I found a fix and passed it on to my Pro brothers. I could have put this kit together and sold it, but that was not my intent.

 

[ditch1000]

Lets not get this thread into something that it was not intended to be. I didn't claim or promise any HP gain. I was witnessing temp issues I thought could be addressed in a cheap, simple manner. I found a fix and passed it on to my Pro brothers. I could have put this kit together and sold it, but that was not my intent.

I'm not stating anything like that. I'm just saying that I think the power deleivery is being held back because of the high coolant temps. Now that this is being brought back under control; the kit will run as promised..... I don't think it is the fault of the kit; it is like you said, when the coolant temps hit 130 then engine detunes itself. We never saw those temps on the stock configuration.
I'm just glad guys like you take it upon yourself to experiment with this upgrade and pass it on to the rest of us. Like you said, you probably could have sold them yourself and made some good money on them... Hopefully someone else does not do that as you were the one to do the leg work on it.

 

[geo]

I'm sorry TRS lol but IMO if you don't do this your hurting your motor even if you fool the putor with a resistor. Everything from diesels to gaspots run hotter and leaner today to satisfy EPA. I don't need it in my 2 skt toy.
I have to say though, as stupid as it sounds, you probably voided your warranty doing this unless you in good with your dealer. Poo won't be okay with allowing the motor to run in top tune FOR EVER lol.

You right though, this will not add a single HP. It will just let you use what you got for longer than 10 15 secs. I would love to see a dyno pull now at 110 degrees on a stocker.

TRS you should put together a kit. It took the better part of a day sourceing the parts and then wait another to get them in. Only 2 hrs from drain-to-burb to install though lol. It ended up to be a 110 Cdn dollar upgrade for me lol and I didn't even do the 5 bucks-apiece-uphere heat shrink clamps!
It would also be real nice to have purpose bent hoses so as the eliminate the restriction-wieght from the couplings. Id like to see 1" all the way instead of 3/4" restrictions along the path. I even "ported" my thermostat housing to be .85" instead of .7' cause I will finish the 1"-all-the-way this summer lol.

 

[snobyrd]

jfyi stogans in gp got a few of these doo stats but no tees, mountin view in Dawson creek will have one in for me this week. but I don't need it now cause I got one at stogans, I also used the stock 1"90* hose , I didn't join it, just rotated it, so I only needed a 1" x3/4" tee and I made that myself since welding is my trade. so really all a guy needs is a tee and a 3/4 90* hose. thanks to TRS for thinking outside the polaris box.
jeff

 

[geo]

Put up a pic snobyrd.

 

[TRS]

Thanks guys.

geo,
Also the water pump cover can use a little clean up along with the water passages in the upper case half.