New Dalton pDrive primary spring (100-360)

[Dynamo^Joe]

New Dalton pDrive primary spring (100-360)
I wrote a small story on my website...
https://www.ibackshift.com/comersus/store/comersus_viewItem.asp?idProduct=137

Over the last 2 seasons with the help of Dalton we been testing different spring forces, test guys verifying their performance, I made several springs varying between the first load of 85 and the second load at 370.

I would go test the first one and switch back-n-forth sleds (same sled, same clutching, test spring in one sled) to verify the difference in what the test spring does vs the original spring. Then send the springs out to test guys for verification. Test clicker 2, 3, 4, varying weights, ramp profiles, etc but the main objective was to explore...

..."how low can we go" on engagement speed on the N/A and Turbo 850.
...and what benefits would be see from it

I pitched the idea to Dale at Dalton for the values between 90 and 370 but the target was 95-365. Dale's spring company could make the closest at 100-360 with the spring materials and how the spring fits in the pDrive it has to last tens of thousands of cycles and not fail - that was the closest "in forces" he could come to my target. It works mint for people who want lower engagement speed and to keep their final forces in the 355~370 range.

I love summer, but I can't wait to drive my sled again.
Down the road, I'll post a few vid clips of engagement speeds at 22~2300 rpms, crawling through the trees at 27~2800. he he
Joey

 

[Boost Monster]

You Rock Joey! Best in the biz! Thanks for all your help this past winter working with you and making my factory T850 rip like it should with your New Clutch Kit! Cheers buddy
You Rock Joey! Best in the biz! Thanks for all your help this past winter working with you and making my factory T850 rip like it should with your New Clutch Kit! Cheers
You Rock Joey! Best in the biz! Thanks for all your help this past winter working with you and making my factory T850 rip like it should with your New Clutch Kit! Cheers buddy

 

[Greg5658]

Sorry to derail the thread, on your website you list two clutch kits for the 17 850, 951 ramps and 967 ramps, could you explain to this uneducated sledder the difference and what it can do for me? I raced my bro in law and his stock but perfectly clutched 600 etec pulled away from me embarrassingly quickly. Obviously despite him having a 100lb weight advantage that's a travesty that can't happen again. Btw I ride primarily in the prairies but go to the mountains too.

 

[GreyGhost]

Sorry to derail the thread, on your website you list two clutch kits for the 17 850, 951 ramps and 967 ramps, could you explain to this uneducated sledder the difference and what it can do for me? I raced my bro in law and his stock but perfectly clutched 600 etec pulled away from me embarrassingly quickly. Obviously despite him having a 100lb weight advantage that's a travesty that can't happen again. Btw I ride primarily in the prairies but go to the mountains too.

I’m no clutching master but if I remember it’s all about weight. I believe the 951 is a lighter version compared to the 967. Allowing for a better and more stronger clutch engagement but I’ll let the master Joey correct me

 

[Utter_Kaos]

Will your kit work on a 175 expert or should I wait to they have been released

 

[Dynamo^Joe]

Hello Gents...
@ Greg5658; in 2017 the 850 summit had a low elevation ramp 951 used for 0~4000 feet. The 967 is a high elevation ramp for 4000~12000 feet.
951 @ 49.4 grams
967 @ 43.5 grams
Your sled might have the 967 ramps installed, and if at Manitoba elevations, then the application of that ramp is too light. At say 1100 feet, you are giving away (by overrev) an estimated 5hp per gram of weight. So say you might be down 30hp equivalent of torque, not being able to accelerate hard because you are not using the correct grams in the primary clutch to make the sled pull hard.
I suggest to remove the primary clutch, and/or use a tool to pry the primary clutch slide sheave over (like tuners do with Poos/Cats...etc) and look at the side of the weight at the tip and see what number is casted into the weight.
The difference now is, IF you stay stock clutching, THEN you will have to run the BRP 951 setup at home (and mister, it will pull harder) and when going to mountains then run the 967 ramps.
...but, IF you get a clutch kit, (if you have 967's) THEN, I recommend to ditch the 967's and buy a set of 951's from your BRP dealer and run a clutch kit. All you'll have to do is change the pivot bolt per major elevation range. Like say you'll run a 21 gram bolt in MB and a 14 gram bolt in Revvy at 7000 feet (as an example for lack of better numbers)
A set of 951's are like $65 bux CDN from a skidoo dealer.

It was not uncommon for a 2017 x 850 summit to arrive at low elevation with the 967 ramp. My own sled came with th 967. I ended up eventually installing the 951. Then tried all the newer, more heavy weights BRP had available later on; 966, 965, etc.

@Utter_Kaos; yes the kit will work in the natural aspirated 850 and BRP-Turbo 850 with 175.

Thanks for asking
Joey

 

[Greg5658]

Thanks! I like the idea of just having to do the least amount of mods for elevation changes. Well I guess I'll have to go see what I've got

Hello Gents...
@ Greg5658; in 2017 the 850 summit had a low elevation ramp 951 used for 0~4000 feet. The 967 is a high elevation ramp for 4000~12000 feet.
951 @ 49.4 grams
967 @ 43.5 grams
Your sled might have the 967 ramps installed, and if at Manitoba elevations, then the application of that ramp is too light. At say 1100 feet, you are giving away (by overrev) an estimated 5hp per gram of weight. So say you might be down 30hp equivalent of torque, not being able to accelerate hard because you are not using the correct grams in the primary clutch to make the sled pull hard.
I suggest to remove the primary clutch, and/or use a tool to pry the primary clutch slide sheave over (like tuners do with Poos/Cats...etc) and look at the side of the weight at the tip and see what number is casted into the weight.
The difference now is, IF you stay stock clutching, THEN you will have to run the BRP 951 setup at home (and mister, it will pull harder) and when going to mountains then run the 967 ramps.
...but, IF you get a clutch kit, (if you have 967's) THEN, I recommend to ditch the 967's and buy a set of 951's from your BRP dealer and run a clutch kit. All you'll have to do is change the pivot bolt per major elevation range. Like say you'll run a 21 gram bolt in MB and a 14 gram bolt in Revvy at 7000 feet (as an example for lack of better numbers)
A set of 951's are like $65 bux CDN from a skidoo dealer.

It was not uncommon for a 2017 x 850 summit to arrive at low elevation with the 967 ramp. My own sled came with th 967. I ended up eventually installing the 951. Then tried all the newer, more heavy weights BRP had available later on; 966, 965, etc.

@Utter_Kaos; yes the kit will work in the natural aspirated 850 and BRP-Turbo 850 with 175.

Thanks for asking
Joey