I have avoided this whole topic for a VERY long time...because it will open up a can of worms and MAY even add more confusion...but I think the time has come and it is near impossible, with my typing skills, to effectively relay what needs to be said.. so, I will just touch on the high points and hope it translates well.
1) Since all sleds have the SAME medium (Clutch, belt, chain, and track) for movement. unless you change one of these "items" AS A WHOLE there can be no more or no less power transfer. It really is that simple!! So, unless you physically are running a DIFFERENT clutch (not clutch internals.. but clutch) or belt, or Chain.. the power transfer from the engine crank to the chain is the SAME! The only time this is not true is if the belt is slipping in the clutches!! If you have continuous, not momentary, belt slippage, then there transfer of energy will be lower. BUT if there is not slippage in the mediums, then the transfer of energy remains the same. Can the rotational speed change? Yes. Can there be a parasite (like a bad bearing) that is robbing HP due to frictional losses? YOU BET!
2) If you have a clutching set up that previously did, say 90 MPH and you change out some clutching component and now you do 100MPH, what you did is change the final shift ratio! Your final shift ratio changed and allowed for the added MPH, not the HP. You did not suddenly find new HP to allow you go another 10MPH... You were simply able to NOW overcome a "blockage" that did not allow you to get to the higher shift ratio.
Think of a baseball being thrown into the air where there is a 5mph head wind. Now throw that same ball , the same way (like your clutches and engine always do) into the air with zero head wind. The baseball will go further and faster. Was the baseball thrown with any more "power" or initial velocity?? NOPE! It was thrown with the exact same amount of energy every-time. Just like your engine turning your clutch... same every time.
So, I think the terms "HP to the track" is a bit misleading.. because the HP delivered by the engine remains the same! Your track is still seeing (if your track could actually see) the same HP every-time.. The real difference is how far your belt is moving UP in the clutch sheaves!
Simply put.. you can not gain power transfer with any system unless you alter a component that is causing loss.
Changing ramps, springs, and helix designs do not change how those components "do their job" in terms of mechanical functionality nor do they transfer any HP that was being "left" at the crank end! The HP at the crank end is ALWAYS there for using and is always the same for given RPM!!
IF any of these individual components were causing belt slippage, then that is a different story..BUT.. belt slippage is NEVER a constant deal.. if it were, you would not get anywhere. Belt slippage , if present, is always a very intermittent entity that only rears its head under certain conditions.
3) OK, so what about dyno sheets that show the HP going up with different clutch components?
OK, let's define HP and maybe this will clear up the whole track HP speed part:
Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have been working at the rate of one horsepower. In this case, you'd have expended one horsepower-minute of energy.
So, HP is directly related to time. This is important when talking about a track dyno. So, the track dyno is measuring how fast you accelerated the track to X MPH. and since HP is directly related to time, one can calculate a HP number to associate with that acceleration.
GOOD STUFF.. But.. what is really being measured is how fast the track was accelerated or how fast your clutches SHIFTED! The engine's HP was always there for the taking and did not change.
Think about this. If you have a sled that does 100MPH MAX in 10 seconds and you make a clutching change and now you do 100MPH MAX in 9 seconds.. You did NOT change the HP transfer nor did you change the final shift ratio. 100MPH , no matter how fast you got there, will still have the SAME final shift ratio every-time! WHY.. Because the belt length/width, gearing, and rpm stayed the same!! so, no matter how you get there, ultimately these components will determine at what ratio 100MPH is achieved and it will remain the same unless something is changed to alter the gearing. It is fixed and will dictate at what shift point you will be travelling "X" MPH! ..Always..
OK, so are clutch kits bad?? Not at all!! SOME can be VERY effective at overcoming a mis-matched factory installed component that is making it difficult to SHIFT past a certain shift ratio and into a higher shift ratio.
DO, they add HP... IMO.. no... the HP is supplied by the engine and is always there.
Do they transfer more power to the track? IMO.. NO...The clutching medium has not changed. it is still 2 clutches, a belt, and some gears,, so, changing internal components does NOT change the "SYSTEM" as a whole.
Can they make you go faster in a given amount of time? Absolutely!
Can they make your sled travel at a higher rate of speed? SOME.. You bet..
Since you are going faster is your sled delivering more HP to the track?? Hmmm.. that is a loaded question.. IMO.. NO.. the HP to the track will be near the same, but what has changed is how efficiently your sled is using the HP that is available for the taking. Meaning...is it allowing for maximum shift or is it fighting a component that could cause it to not obtain the shift point it is capable of???
AGAIN.. this post was NOT to "DUMP" on anybody or anything.. it was simply one person's perspective/opinion on an issue that can be debated probably...indefinitely..