Important >>> Ski-Doo Summit 850 TURBO OEM at long last!!!!!!

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BeartoothBaron

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A bypass valve in most other turbo applications is to allow metered air to recirculate around the throttle plate and allow the turbo to keep spinning. Otherwise when you blip the throttle with a spinning turbo, the pressure will back up on the compressor and stall it. If you want some incredible examples of it, search the audi group B s1 video's on youtube. They did not run bypass valves on those cars and the noises were phenomenal, but it's so hard on equipment. I had an audi 5 cylinder for a time that didn't run one, it was a lot of fun to drive around for the silly noise. It did end up killing the turbo after a couple years.
I was just looking at the pictures again, and I don't see a bypass valve unless it's part of the check valve assembly. Also no signs of a blowoff valve. Could be that the ECU pops the wastegate as soon as the throttle is closed and the boost is low enough that surging and reversion aren't a problem, or maybe there's some kind of dampener that keeps the throttles open enough to absorb it? Pure curiosity here; given the low boost level, I don't see a problem.
 

christopher

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A bypass valve in most other turbo applications is to allow metered air to recirculate around the throttle plate and allow the turbo to keep spinning. Otherwise when you blip the throttle with a spinning turbo, the pressure will back up on the compressor and stall it. If you want some incredible examples of it, search the audi group B s1 video's on youtube. They did not run bypass valves on those cars and the noises were phenomenal, but it's so hard on equipment. I had an audi 5 cylinder for a time that didn't run one, it was a lot of fun to drive around for the silly noise. It did end up killing the turbo after a couple years.
 

BirdmanID

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I was just looking at the pictures again, and I don't see a bypass valve unless it's part of the check valve assembly. Also no signs of a blowoff valve. Could be that the ECU pops the wastegate as soon as the throttle is closed and the boost is low enough that surging and reversion aren't a problem, or maybe there's some kind of dampener that keeps the throttles open enough to absorb it? Pure curiosity here; given the low boost level, I don't see a problem.
opening the waste gate wouldn’t alleviate the problem of pressure on the compressor side.
 

Mjunkie

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I find it interesting that people have such a hard time understanding what’s going on with this setup and who it’s built for. There’s a reason it was introduced in a 165. It’s made for people who ride higher elevations and deeper snow. If you ride less than 4-5,000ft, this isn’t for you. Most people don’t ride 165’s below 4,000ft.

If you want 200 hp this isn’t for you. Most people don’t want 200hp. They just want another 40hp to get through those deep days better. I know a lot of people on other brands who are excited about this sled because it’s a good bump in power without getting crazy.

If you want better power at higher elevation and every day reliability this is for you.


The intake setup is super easy to understand what’s going on. There’s a check valve in the tube between the engine and the intake. When the engine creates a little bit of vacuum, that check valve opens up and let’s air through. As soon as the turbo makes 1-2 psi (I’m not sure of the exact psi, but 1-2 psi makes the most sense to me) that check valve closes so the air is pushed into the engine instead of back out the intake. So simple of a design that I’m honestly surprised that bd or silber didn’t think of it first.

This will change the way manufacturers build higher elevation mountain sleds. Give it 4-5 years tops and every manufacturer will have a similar setup on the market.
I for one will take 200 hp any day as long as it has a factory warranty and doesn’t weigh 2 tons

Until the sledding world gets to that though, I’d LOVE one of these. I don’t want that long of a track though so hopefully 2021 snowcheck will have other options.


Sent from my iPhone using Tapatalk
 

BeartoothBaron

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opening the waste gate wouldn’t alleviate the problem of pressure on the compressor side.
True, but assuming it's a big enough issue, you could get around it by delaying throttle closure and opening the wastegate when there's a big throttle cut. With the wastegate open, the turbo is going to spin down rapidly (I'd guess a full second, at most), and keeping the throttle from slamming closed would allow the pressure it does make during that transient to go through the engine. Actually, opening the wastegate wouldn't strictly be required, although I'd imagine the throttle could be closed more quickly if it were. My guess is there's some ECU trickery being used to manage that situation without the need for a bypass, but for all I know, it could just be so minimal that there's no need to.
 

Carp

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Sounds like it’s running super consistent. RPM AND THROTTLE RESPONSE sound great.
 

Blk88GT

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How does one get a test drive? I was in Island Park this weekend and didn't see them anywhere... stopped in at the dealer in West and they weren't very forthcoming with information either.

I'll be back out on the 31st and would love to throw a leg over one. PM me if you'd prefer.
 

Ace Freely

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How does one get a test drive? I was in Island Park this weekend and didn't see them anywhere... stopped in at the dealer in West and they weren't very forthcoming with information either.

I'll be back out on the 31st and would love to throw a leg over one. PM me if you'd prefer.

... most dealers are just selling them outright. Was told a few things by a dealer...
1) Sleds CAN'T be sold for less the MSRP.
2) They have a 60 day flooring window.
I don't think you will see a bunch of demos running around.

Ace
 

MountainTrashCat

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How does one get a test drive? I was in Island Park this weekend and didn't see them anywhere... stopped in at the dealer in West and they weren't very forthcoming with information either.

I'll be back out on the 31st and would love to throw a leg over one. PM me if you'd prefer.
Shoulda come to Grizzly. There’ll be one there. 😃
 

Blk88GT

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... most dealers are just selling them outright. Was told a few things by a dealer...
1) Sleds CAN'T be sold for less the MSRP.
2) They have a 60 day flooring window.
I don't think you will see a bunch of demos running around.

Ace
If you read up in the thread, there are a bunch of guys who took test drives over the weekend in the same area I was in.
 

wwracer

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How does one get a test drive? I was in Island Park this weekend and didn't see them anywhere... stopped in at the dealer in West and they weren't very forthcoming with information either.

I'll be back out on the 31st and would love to throw a leg over one. PM me if you'd prefer.
Yeah, I talked to Brad about it at Yellowsyone adventures the other day.Sounds like the only thing he had to do with the crew was supplying gas...
 

96-ramair

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... most dealers are just selling them outright. Was told a few things by a dealer...
1) Sleds CAN'T be sold for less the MSRP.
2) They have a 60 day flooring window.
I don't think you will see a bunch of demos running around.

Ace
My dealer was offered an allotment of 12 sleds, only accepted 4 (they have a ton of existing 2020's, and didn't want to end up stuck with them). 3 of the sleds are for sale, 1 is being reserved for a demo, but they're being somewhat cautious about who they let demo the sled. They're going out and showing it off, but not just letting folks take it for a day on their own.
 

sledhead_24_7

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How does one get a test drive? I was in Island Park this weekend and didn't see them anywhere... stopped in at the dealer in West and they weren't very forthcoming with information either.

I'll be back out on the 31st and would love to throw a leg over one. PM me if you'd prefer.
Get on the phone dealers in the area. Many should have a dealer demo, I’d think. See if you can arrange to demo one. Well worth the effort!

I stole my dealers demo, put the first miles on it. It was nip and tuck for a bit there but they came through in the end.
 
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