Is there any math to clutching?

[kinger]

Sort of like the boost hp octane calculator, and the gearing vs top speed calculator is there anything available for clutching, say you input the current weights, revs, etc and then you can modify the helix angles, spring pressures, weights, and it would calculate new revs?

 

[Turk]

Too many variables like
rider weight
engine hp
gearing
track
snow conditions
elevation
air density

 

[kinger]

So how do you optimize it? Ice testing with a radar?

 

[Srxspec]

If only it were that simple! Test, test, test and keep a dang big notebook with all test information! For instance I have logged 155 different setup/combinations in testing with the Apex/Attak models alone!

Previously we would have 2 sleds, one that remains the same and then one where you change things for comparison testing. We now have a Stalker STATS system that allows us to optimize our testing and not require us to have quite as many sleds for testing around the shop.

 

[srxtwins]

[/quote] We now have a Stalker STATS system that allows us to optimize our testing and not require us to have quite as many sleds for testing around the shop.[/quote]

I would like to obtain more infomation on this system. Do you really like the system? Ease of use,is it stand alone or has to be hooked into sled,ect.And of course cost.

Could you help me out on that one?

 

[Srxspec]

srxtwins, I have only used the Stalker STATS system limited as this is our first season with it, but so far it's great to be able to lay graphs over eachother and pick and choose data points!

 

[SledderSteve]

http://www.stalkerradar.com/sports_ats.shtml

 

[RJH]

Short answer – yes.

The good thing is – you will never find the elusive end to clutching.

In addition – there is clutching for trail – oval racing – drag racing – mountain riding etc. Usually today ...stock clutching is pretty good – usually pulling on top of the rpm band as to not put stress on the engine.

My trail sled is set up to save gas – yet tack out when I want it. You run it up to trail speed – back off the throttle a tich – and it’s tricked into up shifting thus pulling the rpm down – hold the speed – saves gas.

When we raced a lot (and won) – back in the day - it really wasn’t testing – as over time you learn what does what. In the beginning – I guess you just throw a lot of stuff at a clutch - record that and gain that way.

Clutching is so sensitive to what the skis are feeling – studs – conditions – engine- that’s why is so intriguing. Just because your engine tacks out to its designed HP – doesn’t mean it followed the HP curve to get there.

I’ve seen so many aftermarket deals – where they just throw in a bigger spring – then add some weight or secondary angle to pull it back down. The problem – your engagement is up in la la land.

We graphed (math) all our springs - I came in from a heat race needed a change – we didn’t guess – we used the spring with the pre load and set we wanted. We also had the (chart) math to calculate exactly where the belt was on the sheave – to achieve what I wanted.

We used an old movie camera initially – but a helmet cam would work today. Just point the thing at the tack / speedo – do your runs – then playback.