Been doing some testing with our 2017 850 Renegade and also our 2019 850 Summit. Both sleds have been shimmed with our alignment tool and have our Poly torque stop.
2017 Renegade has holes drilled in the side panel in the same area as the 19 vent to help with air flow. I use a Razorback belt temp gauge to monitor belt temps, not measuring clutch sheave temps yet. Belt temp ranges from 125-140 most of the time, can get it up to 150 climbing in a foot of powder but you have to work it pretty hard. Once you get the belt hot and take it easier the belt temp will drop back down, something it didn't do before shimming. After running it hard and you stop the belt temp will go up 10-20 degrees for 15 seconds or so and then start to drop. This is telling me that the sheaves are warmer than the belt and it's the heat going into the belt as the sheaves transfer the heat to the belt. I'm measuring the belt temp when it is in the secondary. Once you start moving again the temps drop back down to the normal range. After 100 miles of testing I put Laflamme Racing clutch weights in the primary, only change. Overall the belt temp went down a few degrees with this change. Last year with the sled stock the belt temp would get up to 180 just trail riding 50-70 mph. Overall very happy with the results, hopefully everyone that used our tool is finding an improvment. Very little belt smear on the primary, last season had much more.
2019 Summit 154. Shimmed motor and installed poly stop before riding so don't have a before and after. First ride out the belt temp was 110-125 most of the time but the air temp was about 10 degrees. Clutches were nice and clean. Second time out belt temp was 120-135 and air temp was 30 so air temp really affects it quite a bit. Can get it up to 140-145 on long runs hard on the throttle runs Did more testing yesterday with camera looking at primary clutch bolt to verify work done with the Renegade, overall matched up well. Going to keep the .75" preloader load for a good spot to align the clutches. Did some cam testing without the clutch guard on and noticed a good 20 degrees higher belt temps without it. Temps went back down after putting it back on.
The Summit comes with a 531 belt which was quite a bit longer than the older BRP belts. I just got a Seek thermo cam to see if it would be a good tool to fine tune the clutch offset number. Thought was to take video of the secondary to see if one side was hotter that would be caused by the belt rubbing the sheave more if the offset was off. Put a couple links here, these are first tests with Summit, one is with 3mm shim in QRS and other is with 1.5mm shim. Overall the video gave more questions than answers and I think it will get some discussion going. It looks like the stationary sheave on the P drive with the wobble is causing more heat on that side of the belt. Some have mentioned that when they gun the sheaves the wobble sheave is always the hottest, could be from wobble or just it's getting all the heat from the crank, not sure. Need to do more testing to try and figure that out.