Over reving on the 850T

[Summitizer]

The difference is BRP didn’t leave any adjustment on the table. Years past you could be 200rpm high and drop to clicker 2 and Cary on with life. This year they have left customers with no solution and no adjustability. Sure it’s a simple fix but the parts to do so should have been included with the snowmobile. Not all of them are doing this but they should all come with both sets of bolts.

There is also nothing wrong with the factory calibration, it works, it gets great belt life.

well spoken Maxwell. That was the problem to start with. So working with our dealer we now have both sleds just rocking. They replaced and installed what we needed and bingo....7900 all day with some clicker adjustment still. We are happy happy happy. Those turbos may not be for everyone but they are sure a lot of fun.

 

[turboetech]

And from my experience not too many guys riding the 850 turboes are having trouble lifting the skis over a fallen tree when they ride around with the skis 4 ft in the air on a stock one....lol... but man it sure looks cool

 

[1709]

Gents, please don't get upset with me. Im not trying to create a pissin contest.

From my testing and the feedback i get from test guys, there's 2 distinct track speeds.
Think in slow motion...

From a start, you pin throttle and the track accelerates and I see...
1] spike track speed.
then a few moments go on and I see...
2] equilibrium track speed.

The spike track speed is; you pin throttle and there is a momentary high track speed number.
Time goes on (thinking in slow motion) vehicle speed is increasing and eventually the vehicle-speed-itself stops increasing(accelerating) and
...you see equilibrium track speed.

There is a gap between spike track speed and equilibrium track speed.
Equilibrium, meaning the condition of where competing influences are balanced.
A guy will say out loud to his buddies; "holds 45mph track speed". Ok that means in his pull he's getting 45mph track speed and it holds there. The condition of full throttle is matching the load the sled is seeing and result is 45mph track speed. That's his equilibrium track speed.

But, go back in time, he might have seen 48mph track speed for a moment as the sled is still accelrating before the sled hit equilibrium track speed.

That 48mph is the spike track speed.
That 45mph is the equilibrium track speed.

My experiences gearing faster [on my kits] will show a bigger gap between the spike(s) and equilibrium(e).
Like say a 21 will give 48(s) and 45(e)
A 22 will give 50(s) and 44(e)
A 19 will give 48(s) and 47(e)

Ok throw a wrench into the works. When you hit equilibrium track speed (47mph) "LET OFF" the throttle and pin it again.
Question; did the track speed recover to 47mph, yes or no?

What we found is with a taller gear, when you let off (severely changing load) and try to recover, the track speed recovery is slower. A faster gear lifts the front end slower when in motion, off/on throttle. A lower gear, the front end lift is more abrupt, skis lift quicker. Can come into something hot/fast like a deadfall tree and time full throttle closer to it to get over. With a taller gear the front end lifts slower after you let off throttle.

I want my kits to have equilibrium track speed as close to the spike track speed. When the driver lets off throttle and back on, bang, track speed gets right back there now. And the rider can feather throttle and listen to the whirl of the track follow his thumb. Objective is smallest lag. Let off throttle, track whirl lowers, press throttle, track whirl follows your thumb. I find a taller gear in tree riding there is a lag "spongy feel" from thumb to track.

Tested 22, 21, 19-53 and 25&24-63 and TKI is making one of my test guys a 23 for 23-63 now to be as close to 19-53 as we can.

Note:"gearing taller" guys, are running their own helix and secondary spring.
We're making our own helixes over here. Draw one up, send it off to Dalton and its sittin on my table in a few days ready to go test.

--------------------------------------------

Heh, i have an idea what "top 1%ers" identifier is. I suspect its a label made. so its users, can put everyone else in a box, label "them" 99%'ers" and dispose of them by a political mechanism "im cultured, you're heathen". Basically kicking the box off the cliff.
Hmm, I see an idea to make a "T-shirt" "im a 99%er" to go with my "infidel flatlander" t-shirt i made a few years ago.

Joe,
but as you know gearing is specific to each person, many things come into play when it comes to gearing, clutching, Elevation, rider weight, horse power, and lug height, length of track,

and snow conditions, trail riding, deep snow riding, the only way to tell is MARK your clutch, why guess ? we have been doing that for years in the mountains,
horse power sleds will handle higher gearing, specially on the turbos, on N/A sleds yes gearing down is always a good thing, but now the manufactures are starting to figure out that they have always geared to high and are bringing out their sleds with lower gearing (Mountain sleds) going up to a 22 tooth top gear is only 3 mph faster, not that big of a change, and yes if you weigh 240 pounds it will not help, but if you weight 175 pounds it does help, gearing on a 3 inch lug track is different then a 2.5 lug track,
<<<< I want my kits to have equilibrium track speed as close to the spike track speed. When the driver lets off throttle and back on, bang, track speed gets right back there now. And the rider can feather throttle and listen to the whirl of the track follow his thumb. Objective is smallest lag. Let off throttle, track whirl lowers, press throttle, track whirl follows your thumb. I find a taller gear in tree riding there is a lag "spongy feel" from thumb to track.>>>>
Yes I agree that`s what a person should have but that comes down to clutching, gearing up 1 tooth is not a big difference in the trees, not where we ride 3000 to 6000 feet, have tested both gearing. ski doo says best all around gearing is 21/51 about the same as 22/53.
now this is on the turbo sleds not on N/A sleds. I feel you are talking about N/A sleds, you don`t have a 850 turbo sled do you ? not saying you are wrong, just pointing out many factors play into gearing.

 

[1200]

Sounds about right to me joe. There's another part of clutching nobody talks about that is who is riding the sled. I can ride around all day just fine but u put my kid on and he is got the sled pinned up the hill and down no mercy the belt is hot so for him a geared down sled helps him and works better just because he's an animal. There's more to it than just weights and springs gears, its how u ride and the conditions you ride in .

 

[turboetech]

Gear a high hp turbo sled up and it slows it down yup sounds ABOUT right.... lol

 

[turboetech]

Here is another point no one has brought up yet..... these 850t sleds are wheeling all over the mountain... let’s say you have 40 % of the track in the snow and 60 % in the air wheeling hens the sled is not loaded up and hens pingin off the rev limiter....if you tuned your suspension to load your sled with more track in the snow your sled won’t over rev and you will save time and money clutching a sled that very few rider even need....remember I’m not selling anything just some free advise... warming up so I think I will head to the mountains with my slow geared up turbski...

 

[Dynamo^Joe]

i never said you or anyone was wrong or in error and i dont deny what you did come to pass. I said what i said from my own tuning and from what i use to gather data.
I can describe what's happening; and there's the rub. People get defensive. Im not attacking. Im just saying what i see and collect from testers and customers.

Just got off the phone with a guy in Colorado @ 130pm. House at 7500, rides at 9500 feet. Blower Pow. Hill 8~9% incline, to the bar. Sled pulling sounds like 8 grand. Feels like sled is stuck in 3rd gear (his words) sounds like good rpm, dont pull hard, feels there's more pull left on the table. Goes back. 22 gear next day, same conditions, feels worse when sled starts to push snow with bumper, belt temp alarm going off even more.

Should he gear 23 now?

I asked him if he can see the tach and he laughed "no". Just feeling.

 

[Dynamo^Joe]

Gear a high hp turbo sled up and it slows it down yup sounds ABOUT right.... lol

I try to be competent in seeing what kind of capacity the owner expects to get out of their turbo sled.
I always get the "what should i gear" question from aftermarket turbo owners.

Ok, back at the customer...
What is the highest most reasonable track speed you expect or "need" to do. Here is why...

Gearing depends on what track speed you need to do.
what is the maximum top track speed you “need” out of your sled? I dint say “want”, everyone wants 150mph track speed in the snow.

This is why I said “need”, like a state that requires relief.

I wont be able to sleep tonight unless I get "X" track speed goin in "Y" snow.

Tell what you need and be realistic and reasonable.

Choose a maximum top speed you “need” to achieve.
.....Then you can choose a gear set to achieve that objective and work backwards to the start.
Its forcing you to draw a line in the sand because you can't have your cake and eat it too regarding "lower end".

And we'll gear for your objective track speed as close to 1-1 ratio as possible.

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Im about to help someone with 240hp. G4 x 165 x 3.0, #310 rider.
Expects to get 65mph track speed.

20 gives 60mph
21 gives 63mph
22 gives 66mph
23 gives 69mph
24 gives 72mph

...so which gear should he start off with?

 

[turboetech]

Seems simple to me sell the g4 and buy a sidewinder trimmed up to 300 hp or spend a bunch of money trying to achieve something unattainable.... sorry for the high jacking of a simple over reving issue

 

[turboetech]

Is the fat bast..ds sled over reving Joe? Or is it crying buy a sidewinder?... lol... I don’t mean to hurt anyone’s feelings...help don’t hurt...

 

[kanedog]

I try to be competent in seeing what kind of capacity the owner expects to get out of their turbo sled.
I always get the "what should i gear" question from aftermarket turbo owners.

Ok, back at the customer...
What is the highest most reasonable track speed you expect or "need" to do. Here is why...

Gearing depends on what track speed you need to do.
what is the maximum top track speed you “need” out of your sled? I dint say “want”, everyone wants 150mph track speed in the snow.

This is why I said “need”, like a state that requires relief.

I wont be able to sleep tonight unless I get "X" track speed goin in "Y" snow.

Tell what you need and be realistic and reasonable.

Choose a maximum top speed you “need” to achieve.
.....Then you can choose a gear set to achieve that objective and work backwards to the start.
Its forcing you to draw a line in the sand because you can't have your cake and eat it too regarding "lower end".

And we'll gear for your objective track speed as close to 1-1 ratio as possible.

--------------------
Im about to help someone with 240hp. G4 x 165 x 3.0, #310 rider.
Expects to get 65mph track speed.

20 gives 60mph
21 gives 63mph
22 gives 66mph
23 gives 69mph
24 gives 72mph

...so which gear should he start off with?

My guess is the 21 tooth cuz he a big guy. It should rip his arms off.

 

[Dynamo^Joe]

Yep, sticking with 21-53 for now and see what that does in the clutch. The felt marker trick will be a good record of what's happening compared to his feedback.

 

[Summitizer]

Anyone with an 850T that has not yet checked their max rpm may be leaving a lot on the table. There is a big difference in performance if not setup correctly. Have a look. These things are fun fun fun.

 

[yellow jacket]

What are they supposed to be reving at for peak performance

 

[Summitizer]

7900 but we have found a little under works too. You will notice quite a change when you get it down there.

 

[yellow jacket]

Thanks for the info!

 

[Big A]

well spoken Maxwell. That was the problem to start with. So working with our dealer we now have both sleds just rocking. They replaced and installed what we needed and bingo....7900 all day with some clicker adjustment still. We are happy happy happy. Those turbos may not be for everyone but they are sure a lot of fun.

What dealer are you working with Summitizer that took the time to help? My dealer is taking a very different approach and my opinion is that of Maxwell's, They completely missed the Mark with weight in these sleds, I'm often seeing as high as 8300 sustained rpm.

 

[Summitizer]

The gang at 54north. They have been on it from the start. Your dealer has to open a case with brp to get anything done. Brp will not do anything if they do no see the numbers of sleds effected. My complaint from day one was there is no adjustment for us. Just pay. This is not a tuning issue it’s a complete calibration issue. It’s wrong and I would love to know what the brp ambassadors are running in theirs. CKMP is at my riding elevation. You cannot tell me they don’t see it. You will not believe the difference at 7900rpm. Hope to helps.

 

[RGM]

I threw a bunch of weight at my clutch and still overreving and primary wound all the way out. Going to move up one tooth on top gear. Anyone no the part # I think the chain and sprockets are different for the turbos vs NA

 

[fredw]

Try adding more helix as well, stiffer secondary spring..

A harder up shift increases load and might help as well, doos clutching has always been a challenge for them