Polaris p85 on 850 doo

fredw said:

Dave at redline was putting p85 on some of his first built 850kits when the pdrive was being a nightmare to understand, and the belts were not lasting a day..

remember taking a scale out and he had them under 10 lbs and pdrive almost 14 I recall.. but don’t quote me.. he said they ran very well but needed to machine surface of something and went went a specific belt..

he since has went back to the pdrive with his new externals and better 371 belt and it’s been pretty stout primary..

I want to as well try the tra race clutch on it soon as well since it’s a fair amount lighter and fits right on, few buddy’s running this setup and the primary weight difference shoes quick on spool

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Exactly how I ended with the p85 from redline. The clutching that came with my turbo kit wasn't good at all. In saying that just bolting on the p85 didn't make it perfect either. For the helix that I was running, It required different springs. Several different options now for a good pdrive setup.

About 1200km on P85 in my sled and no issues.
Mountain Majic sled, team tied secondary.
I would guess at half the running temp of stock doo egg cooker clutches.
Can actually put your hand on primary after a pull without second degree burns.

I would like to see this rig sometime this winter. love their builds... Just cant afford one lol

fynnigan said:

Kind of kicking around the idea . Less rotating mass ,almost 4lbs lighter. Heard some good stories and some bad. Vibration etc. . I have it well clutched right now with the p drive but thinking about going down the lightweight trail . Thoughts ?

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Neglecting the brand Polaris and for fun, say it is 4 lbs lighter than a pdrive. Assume the vibration is acceptable, rule that out.

You want to mount a lighter clutch because you believe it will achieve, accomplish, carry into effect, what?

Dynamo^Joe said:

Neglecting the brand Polaris and for fun, say it is 4 lbs lighter than a pdrive. Assume the vibration is acceptable, rule that out.

You want to mount a lighter clutch because you believe it will achieve, accomplish, carry into effect, what?

Click to expand...

put a p85 on my ported n polished t3 xm. Crank went boom in 1500 km. Was it the clutch ..hmmm..

Dynamo^Joe said:

Neglecting the brand Polaris and for fun, say it is 4 lbs lighter than a pdrive. Assume the vibration is acceptable, rule that out.

You want to mount a lighter clutch because you believe it will achieve, accomplish, carry into effect, what?

Click to expand...

Well Joe first thing , you and I have long discussions on the phone and I have used your products a lot . 2 872s ,a couple of rmsha sleds, personnel sled etc. You have a good product. What I am looking for is some lost weight,possibly quicker and snappier power ,like the Polaris can bring . Love skidoo sleds but let’s face it,they are a little chunky. After you get past the half century mark reaction times get slower , sled starts to feel heavier ,and I know that is not the sleds fault but a few pounds here and there helps,a lot . Currently about 20 pounds lighter than stock ,and it shows . A bit of weight off the left side of the sled maybe a tiny bit of performance gain = better days of riding . Hard to say if the juice is worth the squeeze on this idea although. Cheers ... Mike

The clutch is a flywheel, flywheel is designed to smoothen out the power delivery of the engine, store energy and smoothen out the flow of energy cause by combustion.



I removed the starter ring gear off my 09 mod for a test, and to satisfy my curiosity from reading internet topics. Yes back than, I was indexing my primary to the crank, so it went back on in the same spot.

Yep the engine would spin up in RPM way quicker, but I also noticed two major negatives after removing it. The vibration in the running boards increased, and my sleds max rpm fluctuated alot worse than before, so there was a obvious phase shift in vibration/resonance of the machine.

drew562 said:

put a p85 on my ported n polished t3 xm. Crank went boom in 1500 km. Was it the clutch ..hmmm..

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All i know is the clutch weight is designed for correct inertia. [Aaen clutch tuning handbook Vol 2007, Pg 23]
When you strike a tuning fork, it rings.
When the piston makes a power pulse, the crankshaft rings like a big tuning fork.
The engine running at 7900 rpms +/- the engine itself is a structure, vibrating in response to one or more pulsating forces; ringing like a big tuning fork.

The clutch is a mass to dampen and dissipate a vibration and keep a forcing frequency "power pulses" away from the natural frequency the crankshaft rings at. When the forcing frequency (power pulses at 7900ish rpms) is close to the natural frequency of the crankshaft, then a resonance exists. Like when you watch a handlebar vibrate lots, then doesnt then vibrates a lot again, then doesnt; that's resonating.

Not gonna go more than that for technical. When the crank aint gots enuf weight, then the engine can resonate. And when it resonates, even though it turns, it still has displacement pulses back and forth which can cause quicker and excessive wear in less time to clutch wear parts, wearing out roller bushings, etc. The parts wear out faster from resonating. Ok, cracked crankshaft is as-if you see someone hitting a chunk of steel and it fractures, breaking off. Same thing, just happens at "rated engine speed"

im not reading my resume, Im just sayin...I was a vibration tech in a paper mill and learned a lot about this subject.
When I left the mill, I took all my Vibe books with me. What i wrote above is basically parakeeted out of this handbook so you know it aint me, im just parakeeting a smart guy, because i aint gots them kinda smarts.
Basic machinery vibrations: Ronald L Eshleman
https://www.amazon.ca/Basic-machinery-vibrations-introduction-monitoring/dp/B01FGNH8VY

This below is from my own experiences...
If you want to make the engine more quick when you are on/off/on throttle, then tune the settings in the clutch to do it.
Look at any part in the clutches.

• Springs have rates, higher slope of a line makes the engine rev up quicker from one rpm to a higher rpm.
• A primary clutch cam arm/ramp has angles on it, a higher angle forces the engine rev up quicker from one rpm to a higher rpm.
• The start force of a secondary spring makes the engine rev up quicker from one rpm to a higher rpm.
• The helix angle (used at X track speed) the angle of that line makes the engine rev up quicker from one rpm to a higher rpm.

They can stay over there and do the "quickening" of engine speed by lightening the clutch.
I'll stay over here and do the quickening of the engine by clutch tuning
..and we'll get along just fine.

cya
joey

Think you can get this with a polaris primary? click full screen
https://drive.google.com/file/d/1yPQCXBa5-2SXCsbmjwzrOKnNarO9ASD9/view?usp=sharing
...im kinda teasing ya a bit

one of these days i'll post a vid of my own sled at 22~2300 engagement. he he