Speedwerx Supercharger on 20 HC ?

[thump426er]

Hey there, I have a 20 HC with 4500 km on chassis and 3200 km on engine (2 rides on 3rd set of primary and secondary lol). Heavily considering snow checking a 22 cat or possibly poo this year but, if I don’t I’m having this crazy idea of throwing a supercharger on the sled. Only current mods on it are belt drive, can, protectair.

I’d pop a fresh top end in for sure but I have a pile of questions for you guys since I’ve never had a boosted sled.

- should I also refresh bottom end at this mileage if I go boost?
- does anyone have experience with the speedwerx supercharger good and bad? What?
- would I need an upgrade in jackshaft/driveshaft or should I be fine with stock at this mileage?
- can I legit run this as pump gas 91 or will I always need a mix of some sort?

Really I’m looking for any input that may help my decision process as well. Thanks for any thoughts.

 

[ndfb35]

I haven't owned a SC but 2 of my riding buddies do.

They love fuel, it is no exaggeration. They pack at least a gallon every ride no matter what to make sure they can get back home.

They are legit pump gas kits. Even with 7+ lb pulleys. The intercooler allows this.

Neither of them have made any modifications to the bottom end of their sleds but a top end will most likely be done on the the one with 1600+ miles.

I have a turbo and prefer the setup, we'll running turbo to the SC. I'm okay with a little lack of bottom end but riding the SC is a lot of "gliding" since you are always boosting it reacts very fast and is too fast for me but once you get the hang of it I'm sure you'll enjoy it.

 

[thump426er]

Ok, thank you good info. The gliding part is interesting. Wouldn’t have thought that at all.

 

[ndfb35]

Gliding was how one of them described it. Since it reacts so fast when you get on the throttle, let off, glide a while get on it again, etc. Which is similar to when I get into my boost range but with the SC it's the whole RPM range. Throttle chop city.

 

[boondocker97]

Friend has one on his 2019 Alpha that was built by Jason Nethercott. It runs crisp and clean and was 100% pump gas setup when he got it. He upped the boost this year (because he could) so he's blending fuel now. No reason to up the boost for me and I'm 300lb geared up. You do mix a little oil in with the gas (100:1 I think?). Since it has auxiliary injector(s) it's getting that extra oil to the bottom end too. Because it's always on boost it's always using more fuel so the need to have a gas can or a trail tank is real.

He's constantly on/off the throttle due to the positive boost. Even idling around the parking lot. I have pretty good throttle control so I'm not on/off as much as him. Especially once you learn you don't need to give much throttle it gets easier. 1/4 throttle will do the same things 3/4 throttle will on a N/A sled. You can hold it at a steady throttle position and it kind of keeps picking up a little speed. I understand the "gliding" feeling. If you're the kind of person that wants to just mash it to the bar all the time it might not be best. That being said, once you get used to it it's much more controllable that I thought it would be. There's no wild hit. Just more power from idle on and a lot of it!

He changed his first set of pistons at 800 miles. Thinks he'll push it to 1200 miles on the second set. 2018 and 2019s seemed to have more crank issues. 2020+ design might be better, but I really don't know. If you know you've kept the snow out of that engine then might be ok to keep pushing it? Tom at TKI once told me that Nethercott said they noticed more wear on the aluminum driveshaft splines on the supercharged sleds. So a fresh driveshaft might not be a bad idea. I wouldn't worry about the jackshaft. Just check the bearings.

Forgot to add: I wouldn't be sad if I had to ride a supercharged sled. Even with packing a little extra fuel.

 

[thump426er]

I ride a lot of techy tree terrain. Some days are just spread out trees for fun rather than tech but my riding style is very much only using throttle as needed, not just pinned all over. So this may work for me. Turbo doesn’t in trees when I hop on friends sleds, don’t like the pause and don’t like trying to keep in the boost (love the power though lol).

How finicky have the SC sleds been that your guys groups have? Are the kits pretty dialed in terms of fueling, no bogs or running issues? Not many results come up for a search on here to get much info.

 

[ndfb35]

No issues at all with runability.

 

[boondocker97]

Zero running issues on this one. Probably runs better all around than a lot of people's stockers. Guy that rides it has to worry more about making sure his wrap, bumpers, and handlebars are color coordinated than dealing with any tuning or even clutching.

I will say that all of the weight from the kit is on the front end. Water/air intercooler is right up front, head exchanger on bottom of bulkhead under the motor, and supercharger above the recoil. So anything you can do to get weight off the front end while doing this is a good thing.

 

[boondocker97]

Well it looks like I'll have one of these in stable for this season! Getting excited to learn how to ride boost!!!

 

[nytro41]

Look at the solid turbo setup before you buy the SC

 

[boondocker97]

Sled already has the SC installed. Got to ride the Solid kit for a minute last spring.

 

[nytro41]

Sled already has the SC installed. Got to ride the Solid kit for a minute last spring.

oh awesome! SC run really strong

 

[boondocker97]

The Solid kit ran ok. They were still getting it dialed in and I was way too tired at that point in the day to really give it an honest thrashing/assessment of it's capabilities. The turbo kits not having the extra weight of the water/air intercooler is nice. However, I think the lower charge temps with the supercharger will be good for longevity. Was told even on spring days it stays well down in the double digits. You can run up to 2oz oil/gallon of gas premix in the tank and doesn't affect the tuning or A/F ratio enough to be noticeable. Recommendation is 1oz/gal. That's going through the aux injector in the intake so that extra oil gets to the crank and top end. This one I'm picking up was Nethercotts's 2021 so it's definitely setup well and a major factor of why I decided to get it. Already have a trail tank on the way for it to extend the range and hopefully not have to pack another can on the tunnel.

 

[nytro41]

the lower charge temp is nice. although at 7lbs of boost on a turbo for a 20-30 second pull your only reaching around 130. then its back down below triple digits so its really only a few times that it stays above that triple digit which wont hurt the sled at all. the cooler charge temps are nice for sure but also a marketing thing. for 30 extra lbs over a turbo i just cant imagine it. yamaha is only 3 lbs heavier then a SC before you throw an extra gallon on the SC for the fuel usage. I dont know they just dont seem attractive enough to me. they run good. flawless but to much gas noise and weight for me.

 

[boondocker97]

I'm guessing the consistency in charge temp probably helps keep the tuning more consistent as well. Maybe one factor why they run so well. This one is setup at 8lb running straight pump gas down to 6000'. Talking with Jason he said that without clutching changes it will be down closer to 6lb at 10k feet. Adjust the clutching to get some RPM back and it'll get back up to 7lb. Or if high elevation (10,000+) is all a person runs can throw a 10lb pulley on with pump gas. What's the boost gradient like with a aftermarket turbo these days? Mixing any more octane in at 7lb for safety?

Friend here in town has scales for his race car that I'll be putting the sled on to see where it's at weight wise. I'll report back on that for sure. 30lb extra over a turbo seems a little excessive, but I really don't know that for sure. One thing about them burning that fuel it starts making the sled lighter faster!

 

[boondocker97]

Just wanted to update that I haven't experience the "gliding" feeling on this 2021 I have now like I did on the 2019. Not sure if it's improved mapping or something they did different with the airflow, but it starts slowing as soon as I let off the throttle. Probably only got to ride it 200 miles this year with our crappy snow season, but zero issues so far. Ran a bigger trail tank and packed a 2.5gal can first few trips too, but never needed it. Depending on the snow conditions and how much you're in the throttle 10 gallons will get you as much as 50 miles or as little as 25.

 

[Ride2Live]

Just wanted to update that I haven't experience the "gliding" feeling on this 2021 I have now like I did on the 2019. Not sure if it's improved mapping or something they did different with the airflow, but it starts slowing as soon as I let off the throttle. Probably only got to ride it 200 miles this year with our crappy snow season, but zero issues so far. Ran a bigger trail tank and packed a 2.5gal can first few trips too, but never needed it. Depending on the snow conditions and how much you're in the throttle 10 gallons will get you as much as 50 miles or as little as 25.

Just picked up a 2020 MC with a SC and pumped to ride it. Have read some very helpful information on here and just wanted to ask when you mix your oil do you premix or just put directly in the fuel tank and fill up? Was told 8oz of oil for 11 gallons so it's like a 170:1 ratio or 3/4 oz oil per gallon so don't know how critical it is. Was told to check the spark plug gap and make sure they are .018"-
.020" but how often?

Might be way overthinking this but wanted to ask.

 

[boondocker97]

I pre-mix in 5 gal gas jugs then dump into the sled. That way it's always consistent on the amount of oil it's getting. Nethercott told me 1 oz per gallon, and when he was testing with Speedwerx they could actually run up to 2 oz per gallon before they could see a change in AFR with their data. So erring on the side of a little more oil won't hurt. 0.020" gap with BR9EYA plugs is what he wrote on my clutch cover and told me to change them every 500 miles with the oil in the procharger unit.

 

[Ride2Live]

I pre-mix in 5 gal gas jugs then dump into the sled. That way it's always consistent on the amount of oil it's getting. Nethercott told me 1 oz per gallon, and when he was testing with Speedwerx they could actually run up to 2 oz per gallon before they could see a change in AFR with their data. So erring on the side of a little more oil won't hurt. 0.020" gap with BR9EYA plugs is what he wrote on my clutch cover and told me to change them every 500 miles with the oil in the procharger unit.
View attachment 394000

Thank you for the info. Do you also carry a spare belt for the charger and should I also change every 500 miles? After reading your post I bought a 3.3 mountain addiction gas can to pack with me as we ride around 65 miles so don't want to run out of gas.

Anything other info you wish you knew when you bought yours that can be thrown my way would appreciated.

 

[boondocker97]

I don't carry a spare belt for the charger. The extra fuel is added with an auxiliary injector, and unplugging the fuel controller from the 12V power source by the chain case will shut it off. Since that's an option you can ride out on stock fueling. I'd rather do that than try and tear everything apart on the hill to fix the belt. I was told to reach in and check the tensioner/bearing periodically as he had seen those loosen up before. I didn't get any direction on how often to change the charger belt, but I might change it at 1000 miles to be on an every-other schedule with the plugs and charger oil.

I might do pistons every 1000 miles as preventative maintenance too, so it'll be torn apart for all that during that time. My buddy @broz2006 changed his pistons around 750 miles on his 2019 and they still looked good then.

Throttle pull is pretty stiff with these for some reason. Both my 2021 and buddy's 2019 are this way. I have the aluminum intake tubes and they rest right on top of the steering stem. I thought this could have been done better as it's eventually going to wear a hole in the tube.

They don't pull over that hard compared to my high compression 900BB sled in moderate temperatures, but if it's really cold (like getting close to zero) and the sled is sitting outside you might break the recoil trying to start it (it happened). I don't know if it's the oil in the charger getting cold and making it harder to pull over or what, but be prepared. Under certain conditions they will flood when starting. Like if in a warm shop or you just don't get a good pull on the rope the first time. If it doesn't start on the second pull then hold the throttle wide open and it will fire right up.

Also, it won't let me edit the above old post about sled weight. Mine with some lightweight parts was 553 with the trail tank with 13 gallons of fuel. Full details on the build here: https://www.snowest.com/forum/threads/new-tom-cat-is-home.460162/
Stock 2022 Ski-Doo X 165 (9.5 gal) weight = 570 and RMK Boost 165 (11 gal) = 539 for reference. https://www.snowest.com/forum/threads/2022-turbo-sled-weights.461267/page-2#post-4451082