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Gen 4 Turbo Expert STARVING FOR AIR in Deep Pow.

T
Aug 8, 2011
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The key to riding a turbo in deep snow is that you pin it and let it build boost, then let off and let it dump boost pressure. That surge knocks the snow off the vents. It’s a repetitive thing. From the time you take off, you must ride the sled in a much more aggressive on off throttle style so it’s building boost and releasing boost all the time. You will stop having problems. You are riding very uniform throttle settings and that won’t work. We ride snow that deep or deeper basically all year. Super minimal issues if you adjust your riding style.
 

christopher

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The key to riding a turbo in deep snow is that you pin it and let it build boost, then let off and let it dump boost pressure. That surge knocks the snow off the vents. It’s a repetitive thing. From the time you take off, you must ride the sled in a much more aggressive on off throttle style so it’s building boost and releasing boost all the time. You will stop having problems. You are riding very uniform throttle settings and that won’t work. We ride snow that deep or deeper basically all year. Super minimal issues if you adjust your riding style.
DEEP DAYS like that are FEW and FAR between out here.
But when they come, they are NOT TO BE MISSED if at all possible.
 

christopher

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Absolutely! Just take a much more active stance with your throttle use, in and out of it, and you will be much happier with your sleds performance.
So you think just cycling the Blow-Off valve RIGOROUSLY will be enough to start punching through that massive pile of snow on the hood?

My gut tells me the extra vents would be a very good first step this summer, and your technique will be worth trying out next season as well.
 
T
Aug 8, 2011
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You have to do it full time All the time you ride so it never has a chance to build such a pile.
Ive used extra vents on my g4 turbo hood too…but it won’t fix the issue you are having.
 
C

caper11

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Nov 2, 2008
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Christopher.

The G4 has a major hood design flaw, it’s designed like a dish and collects and packs a lot of snow on the top of the hood. Nature of the beast.

I watched your vids and the type of riding in a flat meadow accelerates the accumulation of snow because, there is light constant throttle input and the snow is constantly being pulled to the vents inlet with no hard throttle cycling.
In deep days being more aggressive in the throttle minimizes the buildup.
Give it WOT and get the front end up and let off on the throttle, or stop and clean off the hood before needing more power.

When I had my G4 before I needed to make a turn or get into something technical I would give the left vent a swipe to clean it off to avoid the pop valve under the hood from opening and drawing in hot engine compartment air. Even if half of the snow gets removed, the movement of the sled and the positive air box pressure will remove the rest.
It’s something you learn to do before you need to get into the boost.
You last vid when you were climbing it was a perfect opportunity to get the sled to clean off the intakes, after you swiped the left vent.

Another thing I noticed, I know it’s hard but what was your max rpm? It sounded like your sled was low on RPM or you were not at WOT, which will make your complaint a lot worse on deep days, the G4 loves 8000/8100.


FYI these sleds do not have a blow off, what guys are hearing is the compressor stalling in the turbo and the excess pressure is being released out the wastegate.


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jcjc1

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Mar 8, 2019
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coudn't find it but there's a guy who duct taped shut the intake vents on his G4 and is riding at altitude in deep snow to prove that the secondary intake supplies all the air the engine needs. the sled runs flawlessly, i think about that every time i see posts regarding bogging and air starvation. rode a couple days ago in over the hood snow and my G5 dash stayed completely covered and sled ran fine. maybe the tension on the secondary intake spring can be decreased if that's an issue.
found it:
 
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christopher

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I watched your vids and the type of riding in a flat meadow accelerates the accumulation of snow because, there is light constant throttle input and the snow is constantly being pulled to the vents inlet with no hard throttle cycling.
In deep days being more aggressive in the throttle minimizes the buildup.
Give it WOT and get the front end up and let off on the throttle, or stop and clean off the hood before needing more power.
This is going to be hard to beleive, but.
NONE of that video was on flat land.
100% of it was on slope, and nearly ALL OF IT WAS in fact WOT.
Thats how much AIR STARVATION I was dealing with the entire day.

The video runs start at about 8,000ft and end at about 9,300ft

Flat perspective
DARBY-1.jpg

3D Perspective of the ridgeline I was riding
DARBY-2.jpg
 

christopher

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coudn't find it but there's a guy who duct taped shut the intake vents on his G4 and is riding at altitude in deep snow to prove that the secondary intake supplies all the air the engine needs. the sled runs flawlessly,
In the two short video clips I posted you should be able to HEAR the engine not getting the air it needed.
Almost all the runs I posted were at WIDE OPEN THROTTLE frequently during the video.
I took several other videos that day
Let me see if I can find one where the engine was forced into "Surging" as it struggled for air.
 

jcjc1

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to be clear i'm not doubting the air starvation, i just think it's interesting whatever the actual reason is in light of the duct taped vents vid and that these sleds come with a provision to deal with blocked vents. maybe at WOT the secondary vent can't supply the needed O2 which is further exacerbated by the turbo.
 
G
Feb 18, 2016
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Make sure you stomp out all of the snow from your footwells. The sled is designed to breath even with all the vents on the hood covered but needs to be able to draw air in somewhere to get to the bypass.

I'll get an exhaust bog every now and then but with footwells cleared my turbo never struggles to breath.
 

christopher

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to be clear i'm not doubting the air starvation, i just think it's interesting whatever the actual reason is in light of the duct taped vents vid and that these sleds come with a provision to deal with blocked vents. maybe at WOT the secondary vent can't supply the needed O2 which is further exacerbated by the turbo.
Right there with ya!
 

christopher

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Make sure you stomp out all of the snow from your footwells. The sled is designed to breath even with all the vents on the hood covered but needs to be able to draw air in somewhere to get to the bypass.

I'll get an exhaust bog every now and then but with footwells cleared my turbo never struggles to breath.
I WAS TOTALLY UNAWARE OF THIS!
 
C

caper11

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Nov 2, 2008
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This is going to be hard to beleive, but.
NONE of that video was on flat land.
100% of it was on slope, and nearly ALL OF IT WAS in fact WOT.
Thats how much AIR STARVATION I was dealing with the entire day.

The video runs start at about 8,000ft and end at about 9,300ft

Flat perspective
View attachment 403164

3D Perspective of the ridgeline I was riding
View attachment 403165

Vids and pics are hard to get a perspective on the actual riding area, just by listening to the vids makes me wonder what the RPM is at.
The second vid showed a decent elevation change.
If your sled is not at max rpm on a semi deep day, they will definitely underrev when it get alot deeper, this is greatly enhanced with a turbo.

Common theme with a G4. I have also experienced the surging and lack of power with snow on the hood, and at the wrong time when I needed the power. I had no problem pull a s-it hook and heading back up that hill with snow on The hood. This pic was my 2021 turbo and its maiden trip. The air starvation issue became alot less when I learned what the sled liked and what it didn’t.

cfd86a31c1a4df61d53e965d62b47309.jpg



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