help 08 D8 163" clutching 10000ft+ low rpm

Ride Hard Repair · Feb 14, 2010

Since my late jan rebuild and reflash Im getting my *** handed to me by the skidoos. I'm only pulling at 7500rpm climbing in powder with po 10-58 weights, Bright green primary spring 150-340 and black white 160-260 secondary team springs. Im thinking of going to 120-340 primary and 180-300 springs and puting in different exhaust springs

powerstroke 350700 · Feb 14, 2010

SLP says different exhaust springs at higher elevation!!!!!!!

hardhat32 · Feb 14, 2010

Your 8 should be able to pull 60 gram weights at 10K. How fresh is your springs and your belt.

I ran 58 grams in my 7 with the stock setup, and it would pull more 7500 at 10k

I would be looking at other things before changing your clutching any further.

Longpants · Feb 14, 2010

Im the guy that posted this, i was on my buddies account. Thanks for the advice, your suspicions are the same as mine. I should maybe get it remapped, maybe it didnt work. self diagnoses on the efi stuff sucks. One thing is for sure since the last rebuild the thing is a pooch.

Longpants · Feb 14, 2010

oh yeh, my springs and belt are new that was the first thing I tried.

Longpants · Feb 14, 2010

I know when they rebuild it the last time with the double ring pistons, they also came with a lower compression head

Kleiny · Feb 14, 2010

change the power valve springs your power valves are not opening fully, I tried a lot of weights and springs and the power valve springs made the biggest difference

CO 2.0 · Feb 14, 2010

Might want to try a helix with a little less finish angle... I had good luck at 10K+ ft by going to a 60/40.36 helix from stock. My motor still ran like a pig up top though with low compression. Definitely didn't help with not being able to pull rpms up here.

Longpants · Feb 14, 2010

what color springs? I was thinking yellow

DragonSlayer1 · Feb 14, 2010

Longpants said:
I know when they rebuild it the last time with the double ring pistons, they also came with a lower compression head

Mine was pulling 7600-7700 I put brad worstens head on it and now i'm pulling 8000. My goal is to get to 8200's. It helped. Talk to brad he know's his stuff. My compression changed from 90's psi to 115. brad said it would add about 8 horse.

Ron · Feb 14, 2010

Ride Hard Repair said:
Since my late jan rebuild and reflash Im getting my *** handed to me by the skidoos. I'm only pulling at 7500rpm climbing in powder with po 10-58 weights, Bright green primary spring 150-340 and black white 160-260 secondary team springs. Im thinking of going to 120-340 primary and 180-300 springs and puting in different exhaust springs

It takes more primary weight or less primary spring to open a driven with higher spring rate. The theory is to run as little driven spring as needed to stop belt slip. Going with higher driven spring rate when you can't run heavier weights might work against you. It might work better to reduce the helix angle and increase the primary spring to one of these: 165/310; 165/327; 160/340. You might be able to run 10-60's. If you are only getting 7500 then you are either down on power, have clutch issues (belt side clearance, worn belt, etc) and/or are getting heat in the clutches (clutch setup)-heat drops R's and increases belt wear.

force it in · Feb 14, 2010

mine too sucks at high elevation thinking of exost springs also

towngrunt · Feb 14, 2010

I had similar problems the last 2 years on my 08 only running between the 75 to 76 area. This year seems to run closer to the 79 to 81 mark. Still not quite where I would like it but getting close. I run anywhere from 5000' to 10,000' and up. I have installed a SLP pipe along with the proper clutching, and pink exhaust springs in the valves which is what SLP suggest's, and also installed a PCV. Have all the SLP airbox work and some venting. I do think some of the R's lost are due to clutch and belt heat and am looking into some clutch venting. Also am going to try plugging off the lines running from the solenoid valve to the valves. Maybe in due time we can get all this figured out.

Longpants · Feb 14, 2010

I think I might try new exhaust springs , po 10-56 weights, 120-340 primary spring, and a 160-300 driven with stock helix. Theory being the more rpms you run the higher the compression and torque. I want to get the track spinning at 45-50 mph as fast as possible and have it stay there. If it cant pull rpms with that setup its got to be the efi holding it back, then what do you do about that.

AKSNOWRIDER · Feb 14, 2010

Longpants said:
I think I might try new exhaust springs , po 10-56 weights, 120-340 primary spring, and a 160-300 driven with stock helix. Theory being the more rpms you run the higher the compression and torque. I want to get the track spinning at 45-50 mph as fast as possible and have it stay there. If it cant pull rpms with that setup its got to be the efi holding it back, then what do you do about that.

hmmm..that is alot of sec spring..and very little weight..I dont know if it will even shift out over about 30-40 mph...

Longpants · Feb 14, 2010

If it shifts out at 40mph I hope im runnin 8400rpm. Im only pulling track speed of 35 - 40 now when climbing in powder. before my last rebuild I was at 40 to 45mph. Im going to get my clutch alignment tool and make sure the put the motor back in straight. Thing is Im not making excessive belt heat. With that wimpy motor setup it should be able to handle lots of rpms now

miner700 · Feb 15, 2010

low rpms

some of these guys on this forum, stated to put delrin washers in the secondary with the stock spring.i blew the clutch side piston-mono block-head my dealer replaced all of that and i installed 3 delrins and gained 150 rpms just with that,running 8050 going to install a pc 5 and jin at dynotech says it will be dialed in

thefullmonte · Feb 15, 2010

The new head is working against you at that alt. It is likely you have less than 100lbs of compression. That is problem #1 so I would be looking at having the head modified or getting a new one.
The exhaust valve spring are likely not opening all the way either. So that is problem #2. I think SLP recommends the pink springs. I was going to go with the yellow.
Your stock helix angle probably isn't the best at that alt either. The 160-300 spring does give you the same side pressure at engagement and full shift out with that helix. So in theory it should work good. However, I also think you are going to need quite a bit more weight to pull that. I would find a helix with a 40 or 38 finish angle.
Our trip was cancelled, but I was getting set up for over 10,000 ft. I was going to run a 58/38-.36 helix with a 160-260 blk/wht spring. 165-344 primary spring with heavy hitter weights. Yellow exhaust valve springs. Hope that helps. Keep us posted on your results.

crashnbash · Feb 15, 2010

If you want to contend or beat the dooes and cats, put a pcv on and yellow exhaust springs. That will get you the most right off the bat.

evandaigneault · Feb 21, 2010

i ride mostly at 4-6k feet.. I am currently running 10-64's and stock secondary as i bought the sled last week. Should i change my exhaust springs since im not going as high in altitude? Also, I can get 8100 RPM's but i rarely get to 8200+ unless i've been holding it WOT for a while. I also have 19/46 gearing and a 163" track if that means anything.

Thanks
Evan

help 08 D8 163" clutching 10000ft+ low rpm

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