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Sorry, I am retired and live in Florida.

Bob
Bob I have a question for you.
You seem to be the only pearson that has actualy tested and collecter data on these 900NA's for the clutching and engine, the others are only reporting what they have heared or have verry limited testing, but don't seem to have collected any data like you did, I actualy consider you a reference in 900NA's.

My ride is a 2021 expedition sport 900ACE.
I have setup my Pdrive with the Dalton red, 100-360lb and the QRS with the Dalton DPSS-B/Y/G 54-80lb around 18lb, the stock helix is a straight 42. Gearing is 24T 49B. Running a stock belt with about 1000mi on it.

Rpm's are where I want them to be 7800 some times they climb to 8000 but rarely normally they stay at 7800-7900.

My problem is I still can not get the Qrs to behave properly top speed is very slow to attain and is low this weekend top speed was 74mph gauge speed and my best this season was 85mph.
I did a sharpie ligne on the drive and the driven shives and the drive is used fully the driven still have 1" to get to the bottom

I have just received a Dalton helix 44/40 it will be going in in a few days, I ordered it to have slightly more low end snap and possibly try to get the extra MPH for the top end.

I am thinking on going for a 23T or 51B gear.

What am I missing to get a snappier top end I don't really want to go any faster that 85mph, but I do feel this engine should be able to make it to 85 much faster.
 

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Discussion Starter · #604 ·
Leave the gearing stock. I would recommend winding the secondary spring to 21lbs initial tension per my video or switch to a Dalton DPSS-B/Y/R and set to an initial tension of 16lbs, per my video. Buy a Gates Carbon Drive Belt, see Chris at C&T Power Sports (site sponsor). On any given day you can loose 10mph, it's all about conditions.

Bob
 

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85 is about all your gonna get. I've never had a sled that is so affected by temp or snow conditions. Yesterday morning 5 degrees freshly groomed was hitting 85 gps. End of day 18 degrees and trails were a little loose and it was all it could do to get 74 gps. I run cudney kit. These motors are nice little motors but they just don't have any top end unless conditions are perfect. Part of it for me definitely is the junk slipsaw track I'm going to upgrade next season.
 

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Discussion Starter · #606 ·
Best I did with my modified 900 ACE N.A. was 95MPH GPS. I believe on ice I could of hit 100MPH. The sleds run their best at -10F or lower.

Bob
 

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There is always a give take with any and all mods. Most clutching from the factory with any manufacture can be improved on. With the 900 ACE N.A. it was clutched very soft and the factory springs sagged very quickly resulting in poor "High Performance" operation. For every day riding it was great, but not so great for the performance guys and gals. If clutch mods done per my thread, you will see as much as a 5 sled length difference in a quarter mile run, harder pull off from corners and much improved acceleration up to 80 MPH. There is no down sides to this set up. Mileage, trail manners are excellent. If you have read the responses from this thread and many others, you will know that this set up works. Also make sure you watch my videos "click on link below"!
Hey Bob, My brother has a 2021 renegade with a 600etech, I have a 2019 renegade 900ace. I take him out of the hole up to 40mph, then it's over. If I do what you recommend with both clutches and your secret helix, how will it compare to his stock 600?
Bob, as you can see, I mentioned I have a 2019, I bought springs as per you thread. When I took the primary clutch out and took it apart I realized that it's a totally different clutch than your 2016. Springs are not even close to the same. What now?
 

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Discussion Starter · #608 ·
You have a PDrive Primary.

Primary spring Part #DPDS-DBL This is a Dalton spring.

Secondary is the same.

Bob
 

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what kind of performance gains would I expect to get with these springs, and what should the deflection pressure be for this on the secondary?
You have a Pdrive like Bar said above. His whole build thread is on the Edrive2. Your gonna have to do some of your own research on the Pdrive. You set the secondary deflection so the track just starts to creep while the its off the ground, like any other secondary.
 

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Discussion Starter · #612 ·
They have a slightly higher tension.

Bob
 

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Discussion Starter · #613 ·
Well fellow snowmobilers. it's time to say goodbye. It's been a great run and now it's time to step aside and enjoy retirement. I new when it was time, to stop racing go karts, and now I know it's time, to stop sledding. I may just check in from time to time, but going to move on and enjoy a hobby I have been doing on and off for most of my life (Slot Car Racing 1/32 and 1/24 scale cars). I built a track and hope to start a club. Thanks for all the kind responses over the years and I hope this build continues to help others. If you do as I have listed in the thread, your sled will have a major performance gain, that will put a smile on your face. I believe this is the most viewed thread on the site and was very happy that I was able to contribute. I never expected the thread to do so well. I am humbled by the experience.

Great Riding you all until we meet again.
Retired: Venice Florida, Where Paradise and Sunshine do not end. 🌞😎

Bob
 

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Bob,
This time it sound official, have a good retirement and have a lot of fun with those slot racing scale cars.
Enjoy that Florida sun.
I think my sledding season is finally over this weekend it will be poring rain, it will probably kill the trails, I can't complain I did just shy of 2000mi.
 

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I also rounded and polished the edge of the butterfly. You do not want to change the diameter, just round the edges with a fine file and then polish with 2000 grit sand paper.

View attachment 1629258

The butterfly has a sharp edge.

View attachment 1629266

Rounded edges and polished.

I just need to put the sled back together, clean & polish one more time before the snow gets here.

Update 11/22/2017: You will need to have your TPS reset or your idle will be erratic and possible check engine light. After that you will be all set to go.

Bob
Hi Bob. Love the write up and work you’re doing. Question. How do you reset the TPS?
 

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Congrats on retirement. But I would never retire to FL. Lived there for 2 years and hated it. Too hot for my blood. I want to retire to a place that has snow every day of the year.

Anyways, enjoy retirement. I'm picking up a used 2018 Blizzard 900 Ace tomorrow. I don't think I'll do any of these mods. But nice knowing we can make a little gain in performance.
 
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