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    Here is an example of a viable "Group Buy"

    http://www.snowestonline.com/forum/showthread.php?t=269222

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    As ALWAYS, since DAY ONE of me becoming a moderator, I have pioneered, supported and encouraged vendors and mfgs in getting the word out to our readers with "New Product Announcements.

    Have a great season.

    From this point on, all vendors/mfg's promoting Pre-Season tiered sales programs, in the Polaris Forums, that are not paid advertisers will be appropriately moved to the swapmeet section of the forums.

    MH

Silber Turbo Axys Lessons Learned

I just bought a Silber turbo for my 2016 Axys. I thought I would post some useful things I have learned and am learning in my setup process. Maybe this will help some folks. Maybe not. The setup rips, save for a couple little bugs to work out. I am running at 10000' and up. I have been playing with the 3 and 5 psi springs. I wont mess with the 7 until I get the lower boost dialed and we get more snow. I am also on a 155 so keeping the front end down in hero snow is enough work with low boost.

Turbo bark/ surge/ flutter: This is not a good thing even though it sounds really cool. I know a fair bit about this in my automotive experience. It will cause your turbo to slow and loose boost as well as put unnecessary stress on the turbine/ compressor wheel. notice that the Silber does this more than others. What I found is that the BOV spring is too heavy for the low amount of vacuum the 2 stroke produces. I have cut some coils off of my BOV (per Justin Silber's instruction) and the surge is much less. I will keep playing with this. It should open with about 7 PSI vacuum or just by sucking on it with your mouth (seriously though!) :whistle: . Mine was opening at around 15-17 psi in stock form which is fine on a 4 stroke. You should get a one time sort of psst sound when letting off the throttle. Google turbo surge, then google turbo blow-off valve. This Silber blow-off is fairly quiet as it is and internal BOV so you may not hear much of anything when letting off.

Waste gate Springs/ Gauge/ Boost controller: I have not put a boost gauge on yet, however I am almost positive I producing more boost than the spring rate. With the 3 psi spring, I was able to climb just about anything even with a couple feet of fresh. I have read other posts saying to add about 2 psi to whatever spring you are running. I plan to add a gauge and a manual boost controller to have full adjust ability on the fly.

Fuel: I tried standard 91 ethanol fuel. She ran great until making hard pulls at WOT. I got DET even with 3 psi whether in ethanol or non- ethanol mode . I switched to 100% avgas and no more DET. This however gave me a bottom end bogging whether in ethanol or non- ethanol mode. I believe the 100% 100LL is causing too cool of a burn at such high elevation that it is causing this effect. The best I can describe this is that it feels like a carb that is too rich and loading up the plugs. I will be tapering avgas until I find the perfect mix.

Clutching: Plan to spend 500.00 on some custom clutching. The Silber setup works and keeps the clutches cool, but has some less than desirable characteristics for boon docking. I find that it has a strange hanging effect when decelerating and engages pretty harshly. I have verified that all clutch parts are in stellar condition and moving freely. The stock setup worked flawlessly and was very smooth.

Quiet exhaust: I opted for the quiet muffler. It truly is quiet. Close to stock with a nice tone to it. My ears aren't ringing at the end of the day and less people are pissed at me. :D

Other Stuff: Silber will only use the tune they have built. Don't plan on them tailoring any tunes if you are having issues. My unit was a little off on fitment. I eventually hammered it into place. Silber offered to repair, but I don't want to disassemble and send back. Silber is fairly helpful on support, but will assume that most issues lie within your sled. I can understand this to an extent as there are a lot of folks who may attempt this install and not really understand how things should work. I would always suggest to go through your sled completely before installing a kit. Install new belt, set deflection, check cylinders, pistons, reeds, and clean ex valves.

Let me know if you have any further insight that can help me or anyone else installing and tuning a turbo.
 
I figured out that the blowoff valve is from a volvo turbo. It seems to be compatible with various other oem turbos as well. If you need to do some adjustable springs, replacement parts, etc., you can find a lot of parts on eBay for this application.


 
Update: I am seeing much smoother clutch engagement with heavier weights. Not a different RPM, just smoother. I am now at 50/50 avgas and 91 eth. I am still getting some bog around 5100 rpm. I will keep reducing this mix and see if it goes away. Clutching has no real affect on the bog I am experiencing. I tried resetting TPS and saw no change. I have pulled about full coil from my BOV. It now has a perfect pssshhh sound. No more surge and I seem to be able to recover boost better when getting back on the throttle.
 

Teth-Air

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I am a little confused on the cutting of the spring to reduce pressure. Sure a shorter spring has less initial push but the less coil a spring has and the higher the spring rate as there is less metal to flex.
 
I am a little confused on the cutting of the spring to reduce pressure. Sure a shorter spring has less initial push but the less coil a spring has and the higher the spring rate as there is less metal to flex.
For a BOV, the biggest factor to overcome is that initial vacuum to open it up. Once that vacuum and residual boost is relieved (under a second of time), it's really a non-issue since positive pressure is forcing the valve closed as soon as that vacuum is gone. Ideally a weaker spring would be optimal. All I know is that it works the way it should now. I tried it back to back with the vacuum hose fully blocked off and with it connected. Connected feels better coming back on the throttle. It gives a smoother hit with a less laggy feel. The original spring was built for a low to med boost 4 stroke car which has a lot more vacuum on throttle release than a 2 stroke. I dont know if that answered your question. ;)
 

kmg

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I haven't messed with the BOV. I definitely have a bog at about 5100. I was last down to 25% Av and it was still there but not nearly as bad as 50%. At 50 it would actually fall on its face and cause me to get stuck or roll the sled in to the brush below. However I also had a lag from the BOV (as you suggest) after letting off and getting back in it, while slowing up mid -line. So maybe mine is a combination. Done riding for the year.

This is the 7# spring, as I have TRS 7# clutching.
 
I haven't messed with the BOV. I definitely have a bog at about 5100. I was last down to 25% Av and it was still there but not nearly as bad as 50%. At 50 it would actually fall on its face and cause me to get stuck or roll the sled in to the brush below. However I also had a lag from the BOV (as you suggest) after letting off and getting back in it, while slowing up mid -line. So maybe mine is a combination. Done riding for the year.

This is the 7# spring, as I have TRS 7# clutching.
Good to know someone else has that bog issue. Mine was also more noticeable with the AV gas as well. I am hoping for another dump so I can get out and try some things. Not looking promising right now. Time for some moto this weekend! Ill post back if I figure anything out.

As for the BOV, I wouldn't say its a night and day difference and is probably not causing any bogging, but it is so easy to do, makes some difference in spooling, and should help the turbo last longer, so why not do it is my opinion. If you mess up with cutting the spring, there are plenty on the market for cheap. When you are removing the spring, just put some wd40 on the plastic where it pivots, then pull really hard. The plastic part will pop right out. I struggled with this a bit at first not wanting to break it.
 

Snowman.PRO.

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If I am understanding this correctly, you are also saying this will keep the turbo spooled up? So in theory when you are on and off throttle you have that hit from the boost?
 
Could you maybe snap a couple pics and maybe give some more instruction on what you are doing with the bov spring
Spray some lube in the part shown in black in the pick. Yours will be white. Same thing though. Pull the part shown in white from the black. It takes a bit of force, but it will go. Cut the spring where i have it marked in blue. Then you will want to heat the spring on the end and get the end as flat as you can so it sits as level as possible in the assembly. Put it all back together. Put a hose on the end and suck with your mouth. If the valve opens with about the force of drinking a thick milkshake with a srraw then you're probably good. If not, you need to cut a bit more off the spring. I used a vac pump and made it open right about 7in hg.

Go test ride. You should only hear a psshhh sound. No flutter/ surge. That's what you want. Ride a bd turbo. This is how they operate which is correct. You will notice silber is the only one that has the surging. I don't know why they don't address this in house. Same reason they don't address the clutching maybe? 😉
 

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