Over reving on the 850T

maxwell said:

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.

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Dynamo^Joe said:

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.

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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.

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turboetech said:

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

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Dynamo^Joe said:

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?

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Summitizer said:

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.

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