just curious what type of riding or motor are you running that it needs more cooling?
Yeti tunnel cooler
- Thread starter dooman92
- Start date
wwillf01 can speak for himself, but for me, all three of my previous snowbikes (KTM 525 with timbersled, Husaberg 501 with CMX, Yamaha YZ450F with Yeti) would have benefited from a tunnel cooler compared to radiator-only cooling. In my experience, the bike/motor has little to do with it. Though some makes are known to run hotter than others, it has more to do with riding conditions (air temp, snow density and terrain) than motor.
byeatts, you have enough experience on different bikes and different conditions to know most of the below, but I'll elaborate for others that may not.
On fully enclosed engines (be that engine blankets or selkirk enclosure), there are plenty of situations that tend to make a bike heat up too much. All would benefit from tunnel cooler.
- Trail riding where you can not go fast enough to flow air through radiators (such as whoops or when you are speed-limited by traffic or the group one is riding with).
- Long, uphill, deep powder pulls where the motor is working hard for longer durations but little powder is getting blasted against engine/selkirk cooler as you are pointed uphill. The ground speeds are slow enough that radiators either don't have a lot of air flow or, since it's deep powder, they are covered to keep temps up, when you start the long uphill pull, you are not going to stop and uncover radiators
- Situations where the radiators are uncovered but radiator guards have been plugged with snow/ice and impede airflow but the blockage is too far away from radiator to melt away
- warm spring riding where air temps are warm and/or no snow conditions have no powder so no snow is being kicked up to cool engine and speeds don't move enough air through radiators
Sure there are work arounds for all of these such as
- turning out of a steep uphill powder pull to do a quick dive down or across the fall line to cool the bike, then proceed up
- stopping for a couple minutes and letting engine cool on trail
- stopping and packing snow onto radiators or engine or selkirk cooler
Once one gets a tight enough engine enclosure in place, my snowbikes heat/cool more like snowmobiles and there is a reason why sleds use tunnel coolers and not radiators; tunnel coolers are the more consistent and capable way to cool.
Side thought: Most of the benefit of the tunnel cooler is the cooling of the cooler, but there seems to be some benefit in simply having a larger overall coolant capacity to buffer abrupt temp swings. Though the extra capacity may be negated if the user removes/bypasses one of the radiators all together when plumbing in a tunnel cooler. No big deal, though, since the major benefit is the location of the tunnel cooler and heat exchange taking place in a more ideal location than a radiator.
My bikes run within my intended engine temp most of the time on most of the days (160F - 190F), but it would be ideal to NOT adjust my ride around an overheat situation. A tunnel cooler eliminates most of these situation that I run into several times in most rides. I ride with snowbikers that have tunnel coolers and those that don't and tunnel cooled bikes run much more consistent temps (read: fewer high temp issues) than those of us without a tunnel cooler. Plus way less, or no, messing around covering and uncovering radiators throughout the day. Might be an added expense and time to install a tunnel cooler, but to me, they would be worth it to eliminate, or even greatly reduce the number of times I experience, the above.
Tunnel cooler compatibility was a large part of why I ordered a 2020 Yeti rather than other brands (before it surfaced that the new brace might be non-compatible) hence why I'm so keen on hearing first hand experience of installing on a 2020 or later Yeti. A tunnel cooler would be the cherry on top of my favorite-to-date snowbike build and is the last item on this build that was in the "very important" category. Only major other thing is in the "nice to have" category and that is a tunnel-mounted gas tank with fuel pump like some friends have done on other brand kits, but still trying to figure out how to incorporate a 5 or 6 gallon tunnel tank onto the Yeti, but that is a topic for another thread! Ha.
Interesting your bikes don’t ever overheat. In Utah conditions which are constantly changing it is super annoying to be adjusting engine jackets/radiator covers etc. Best solution is to leave it covered and run a tunnel cooler. Works in every condition including when it dumps 2 feet at the end of may overnight then hits 60 degrees by 10 in the morning.
Mountain riding steep trees. . If you don't want to have to take jackets off and on through the season and have crazy temp changes then the tunnel cooler is the key. Here in Utah especially in spring you can hit 240s and up pretty easy whether it is the 2 stroke Yamaha or the 4 stroke ktm... even with a fan. There are certain times also if snow isn't hitting g the cases on the super steep heat builds fast. Combined with our bikes we log about 250 engine hours in a season so we heat every type of condition. I try to make it simple. Do I have to have one no... but its more of pain than having one. I would like to add the Selkirk cooler helps but still not a tunnel cooler.
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I'll second that bit. And, I plumbed my Selkirk "outlaw" style, meaning, opposite of the manufacturers recommendation. Selkirk wants you to plumb their heat exchanger to the bypass circuit of your thermostat so the cooler gets all the coolant when the thermostat is closed. I did that at first, but then re-plumbed the Selkirk cooler to be on the "thermostat open and radiator" circuit of the cooling system and it works much better. To me, when an engine is below the temp you want it, the last thing you want to do is run your thermostat-closed bypass line to a heat exchanger to cool off the engine even more. The C3 thermostat itself has enough of an internal thermostat bypass hole that the radiators and selkirk get some warmth to them even with the thermostat closed, so it still keeps the snow melted off the radiators and selkirk heat exchanger. But the way I plumbed it, the radiators and the selkirk heat exchanger only get full flow when the thermostat opens.
I have a 192F C3 thermostat. Plumbing the Selkirk heat exchanger this way really makes a difference compared to plumbing it on the bypass loop so it's always cooling even with thermostat closed. Anyway, would I do the Selkirk again? Absolutely. Love the extra coolant capacity, the way it closed off the engine and exhaust and radiators, and like the heat exchanger to supplement my two radiators. But, I still want to add a tunnel cooler to get a solid temperature-regulating solution like only tunnel coolers can due to their proximity to the track pushing snow, ice dust and air over the tunnel cooler heat exchanger in all snow conditions (solid ice on a trail may require scratchers, but great to have that option rather than those spring morning runs on boilerplate ice trails requiring repeated pull over and shoving snow on radiators and engine).
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Yep I did the same.. the other way did not make sense ..
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wwillf01,
How's the tunnel cooler install coming along on the 2020 Yeti Freeride? Any pics during the install or after would be great, plus any install insight would be appreciated. Thanks.
interesting results here . All our builds 450 and 500,s fight to keep temps up, They will hit 200 on trail if the rad covers are on, Pulled off temps hover at 170. On the mt I typically leave one cover on all the time and if cold day both are on and temps are around 160. Never have we had temps climb with covers off, WE run water heated bars which is just like an additional radiator for additional cooling. In fact the heat sink of the water heated bars has more surface cooling than the selkirk additional cooler. Also we know how important weight is when floating on snow and the Selkirt with fluid is over 15 additional lbs. A motor thats not mapped properly can have a 40 degree temp swing as well. The 137 SS is soo fast we get loads of air through radiators! lol
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Run the selkirk and 2020 yeti freeride... I like to keep everything covered and not mess around playing the game adding and taking stuff off. In Utah March through April you could be riding in 60 degree days a lot. In the dead of winter not an issue but as winter progresses the Selkirk does such a good job sealing everything off like a snowmobile you can get hot on the steep and slow. Or the Initial climb up the mountain 3k In a single climb through the trees can get it toasty. Now weight wise you need to subtract radiator gaurds and skid plates you normally have instead of the kit.
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no worries, My carbon skid plate weight is very lite, The REV up covers are totally enclosed and at half a pound of weight. I had the Selkirt system here and would not install it and the weight was horrible, Totally enclose motor and head pipe and then claim more cooling is needed so they add a bottom cooler??, Do you see a problem with that concept, again with proper mapping them sunny warm days still hold temps at 185, however this is with water heated bars which is an additional cooler.
Byeatts. It is getting harder and harder to take you seriously.
How can you say that holding the proper temperature is all about mapping? All of our bikes are mapped properly thank you.
mapping alone can easily swing temps 40 degrees. a lean map will have rising temps and really rich will never get hot, Of course the motor needs wrapped to keep snow from hitting the cases, any snow on the motor will suck heat out quickly However take a wrapped motor and richen the mapping and you will see a huge temp drop . This is not rocket science and simple to comprehend.
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what specifically is confusing ?
ok.......one observation, after sucessfully wraping our KTM engines and running heat excangers, on our two bikes ARO/RIOT, temps run 186 on my 500, 191 on dan's big bore 500 something used to be xs 450.......just the variation in thermo bob thermostats.
I haven't seen any temp differences playing with DANs yellow box. Too lean to start, and too lean popping and then rich, 191 until you shut it down. Actually, my 500 mapping is so far superior running around 190 always as compared to a couple of years of my wrapped bike that varied between 130 to 190 depending upon the day, the snow, cutting sidehills or a trail, my KTM cannot perform under 175 degrees for sure.
I haven't seen any temp differences playing with DANs yellow box. Too lean to start, and too lean popping and then rich, 191 until you shut it down. Actually, my 500 mapping is so far superior running around 190 always as compared to a couple of years of my wrapped bike that varied between 130 to 190 depending upon the day, the snow, cutting sidehills or a trail, my KTM cannot perform under 175 degrees for sure.
Yellow as in C3 box? They seem to be pretty good and tuned well, the PR2 on several of the 450,s was so pig rich temps would not climb past 130, same bike no other changes with C3 ecu now runs 170 most all day, Any exposed aluminum will have the heat sucked out quickly and very important to assure snow is kept out, On Timbersled sled and CMX the tunnel is open and theres allot of snow being tossed on the rear of the motor, we have made a shield to prevent this , Yeti and Camso have a enclosed tunnel and not an issue, We have built and tested and compared everything on the market and some are simply snake oil. totally enclosing the headpipe does creates a problem with overheating as many of ewe have noticed and the tiny cooler they added is simply not efficient and the system is very heavy. What I see are many who spent the $ 700 are trying to justify their purchase when it can be done with much less weight , maintain temps and without overheating problems. I see this thread being an informative source for those looking for the best method, the goal is to provide accurate info and not simply justify a ones purchase. One area that were addressing is a thin neoprene Velcro cover that prevents snow from taking heat out of the water heated bars.
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Byeatts,
To clarify, this thread is about the tunnel cooler that C3 makes for the Yeti kit; not about the Selkirk engine surround. While I did mention the selkirk in response to one post, this thread is about a true tunnel cooler for the yeti. I haven't seen any argue for or against the selkirk in this thread; only argue that mqny of us run into situations where a tunnel cooler would be beneficial and make it easier to keep consistent temps. That is why I'm interested in reports of this C3 tunnel cooler on 2020 yeti (because the new brace may complicate the install).
To clarify, this thread is about the tunnel cooler that C3 makes for the Yeti kit; not about the Selkirk engine surround. While I did mention the selkirk in response to one post, this thread is about a true tunnel cooler for the yeti. I haven't seen any argue for or against the selkirk in this thread; only argue that mqny of us run into situations where a tunnel cooler would be beneficial and make it easier to keep consistent temps. That is why I'm interested in reports of this C3 tunnel cooler on 2020 yeti (because the new brace may complicate the install).
understandable, However they are trying to prevent the overheating which is being created by the Selkirk system .We found this to be the issue and none of our 60 builds have any heating issues, To be informative we need to identify the cause of the problem.
