secondary spring

[sledneck_03]

finding in crusty top pow my sleds pulling 8000 rather than 8200 like it does when in soft pow. sled also pulls 8400 on the trail

thinking of going to a 140/240 red black team spring in rather than a black pink 160/240

current is stock black 140/222

thoughts?

 

[sled_guy]

If it's not holding RPM then you want a little more initial spring.

Lots of folks have been running the black/purple which is 160/240 and that has worked well. Recently (last couple of years) TEAM has been offering the gold/black, 175/240... I recently went to that in a Dragon 800 from the black/purple and it does hold rpm better.

Remember when dealing with springs you are looking at the overall position of the force graph throughout the shift range. I find it helpful to put the numbers in Excel and graph them so I can see the effect.

Try a spring with more initial force than what you currently have and I think you'll find it hold the RPM better.

sled_guy

 

[sledneck_03]

If it's not holding RPM then you want a little more initial spring.

Lots of folks have been running the black/purple which is 160/240 and that has worked well. Recently (last couple of years) TEAM has been offering the gold/black, 175/240... I recently went to that in a Dragon 800 from the black/purple and it does hold rpm better.

Remember when dealing with springs you are looking at the overall position of the force graph throughout the shift range. I find it helpful to put the numbers in Excel and graph them so I can see the effect.

Try a spring with more initial force than what you currently have and I think you'll find it hold the RPM better.

sled_guy

k thats what i wanted to hear. springs are cheap! thanks. maybe ill go black pink...... maybe the gold black......

 

[sledneck_03]

heres what i get from the chart. what looks better for holding rpm? what about a like 160/220?

wait........the stock is a 155/222.

is the first number is the lbs when the springs the longest? and the seconds when the springs the shortest? (at the dimensions the clutch moves 2.2" and 1.1") so saying that it takes 155 lbs to overcome the spring initially. then it will increase spring tension up to 222 lbs at full squish (which is when the clutch sheaves are furthest apart. so what would initial lbs have anything to do with holding rpm at WOT? wouldnt that just give you a higher rpm needed to open the secondary?

 

[sledneck_03]

well. looks like even a 240 finish is too high and going to probably burn belts being im at 2000 ft. Going to possibly go to a 56/40 .36 helix....... or just leave it.

what rpm is peak torque?

 

[sled_guy]

You are right, first number is when the spring is the longest, but it is pre-loaded. 2nd number is at full shift out.

I look at it this way... the spring is what pushes the clutch back up the helix and thus gears the sled down. The faster that happens, the quicker the back shift the better the sled holds rpm.

So yes, a higher finish number affects that... but the problem is that you spend most of your time way below full shift out. By increasing the final number you are actually affecting the area you typically run in (shift area) very little. By increasing the initial angle you are affecting that shift area a lot.

sled_guy