09 m8 snopro. Only pulling 7500 in POW

[montanasledder]

Rode today in incredile amount of powder. 3 feet atleast everywhere. Sled was running great all day but only pulled 7500 on climbs in the powder. Sleds stock 09 m8 153 track. 8000 elevation. should i drop weight? what weights should i try?

thanks

 

[Frostbite]

You could drop a couple grams from your primary weights or add a primary spring with a higher total force.

I just added the SLP Black/Pink 120/340 primary spring last night because I was pulling 7,900ish and SLP suggests closer to 8,100 RPM. I wanted to keep a stock like engagement RPM but be able to pull a few more RPM on top.

The stock primary spring is 120 (or 125)/285.

If you just added a stronger spring it MAY gain you the 200 RPM you are looking for and the springs retail for $21.95.

Good luck

 

[summ8rmk]

My sled was doing the same thing. All I did was put in RK-TEK torsional secondary w snopro green spring 38/36 helix. My sled now turns 7,800 rpm and is a lot faster when climbing in the deep. 75 gram in the primary I ride at 6,000-7,000 feet. but I also only weigh 170 lbs. Maybe the RKT is not the best kit but its the only one I have tried and it is a huge improvement in all conditions over the stock compression style secondary. Reverse might not work 100% of the time. I tried both of CAT's helix's 44/40 and straght 36. Just trying to share my experiance.

 

[1080paul]

I gained 200rpm with Cat's orange/white primary spring.

 

[Griff]

7500 to 7600rpm is more in the peak of the torque and hp curve than 7800 to 7900rpm if your sled is stock. I dropped the the stock 73's and put in 70's due to exactly what you described and lost performance...sled revved past the power curve. Like 1080paul, I tried the Orange/White spring and it was an improvement with the stock 73g weights. I am still fine tuning primary weight but expect to settle around 72g. Biggest improvement for me was a slightly softer secondary spring, Goodwin Blue. My opinion is that if you are going to run this motor stock you have to clutch for 7600 rpm and get used to lugging it...much different than my M7 which ripped at 7900. I ride at 10,000+/-.

 

[montanasledder]

Thanks everyone. I plan to pipe it this summer. Just trying to get it as close as i can for now

 

[Icedog]

I dropped the the stock 73's and put in 70's due to exactly what you described and lost performance...sled revved past the power curve.

I did the same thing (71.5g's from 73g's with an RKT secondary); and had exactly the same results. The stock 73's with the RKT 38/36 kit is workin' awesome though.

 

[Bounty Hunter]

The D&D tan spring for the primary clutch would help. It is 150/330, works great.