Ski-Doo Snowmobiles Forum banner
1 - 20 of 23 Posts

·
Registered
Joined
·
2,726 Posts
Discussion Starter · #1 ·
Good morning. Things are progressing with my MoTeC tunes from Martin. Finally got some time on the snow this past weekend, but only on the back 40, as local trails have not been open due to lack of snow. I have an STM Rage 8 that I will be rebuilding for next year, but for the trail tune this year I am probably going to just go with my PB80 to simplify and get the most out of whatever winter we may have. I have an anti lag set up that I want to use for an upcoming hill drag. The rev limiter is set for 3200 rpm when engaged. Any advice on what spring and puck combo I could use to keep engagement just above 3200 rpm? Thanks guys.

Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
3,508 Posts
I don't know what you plan to run for boost, but I'd guess 12-14 lbs or so, in which case I don't see getting engagement RPM over 3200 with the weight needed for that type of power.

You won't need anti-lag in the snow on stock compression engine anyway. Just leave at an idle and it will still be spinning the track! It will be more important to spend time on your studding and traction than to worry about using anti-lag.
 

·
Registered
Joined
·
2,726 Posts
Discussion Starter · #4 ·
Thx Mike ( I think it's mike). My trail map is 10-11 pounds. Race tune will be 14-15, but just concentrating on the trail tune for now. Are you saying that it will be tough to add enough weight to the PB80 to overcome the spring required for a +3200 engagement rpm and still keep it off the limiter?
My traction is pretty good. Running a 1.5 inch 2 ply intense with 160+ Woodys MEG-1575's. Gives me about .350" penetration. Plus I can bleed air out of my rear AirWave skid for some pretty good launches.

Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
2,726 Posts
Discussion Starter · #5 ·

·
Registered
Joined
·
3,508 Posts
Playing with fire running more than 8 lbs on that pb80. Ask me how I know.
Many are doing it. What happened with yours Randy?

Thx Mike ( I think it's mike). My trail map is 10-11 pounds. Race tune will be 14-15, but just concentrating on the trail tune for now. Are you saying that it will be tough to add enough weight to the PB80 to overcome the spring required for a +3200 engagement rpm and still keep it off the limiter?
My traction is pretty good. Running a 1.5 inch 2 ply intense with 160+ Woodys MEG-1575's. Gives me about .350" penetration. Plus I can bleed air out of my rear AirWave skid for some pretty good launches.

Sent from my iPad using Tapatalk
I ran 10 lbs last week and had pucks loaded at 147 grams with 800/1300 PB spring and 50/44 beige wrapped to 21 lbs. Was a pretty warm day in the mid 30's F.

Engagement was only like 2400 RPM. Less than 2500 anyway. If your anti-lag is at 3200 and hold there, you'll need clutch engagement up at like 36-3700 if anti-lag holds that exact RPM. Not gonna happen with the PB-80 loaded with weight.

Don't forget your race fuel spiked in there with stock compression!

You will not need anti lag or high engagement on the snow. It's going to be blowing the track away leaving at an idle!
 
G

·
My spring cup exploded last year on a lake run at 9 lbs boost. I fixed and sold. It was not a O.D. one, perhaps the reason.
 

·
Registered
Joined
·
3,508 Posts
My spring cup exploded last year on a lake run at 9 lbs boost. I fixed and sold. It was not a O.D. one, perhaps the reason.
I figured as much, but stock sleds are also breaking spring cups so its not related to boost at all.

See the one that just let go on a stocker, it had the new style cup in it too, but Cudney spring and no spring guide which CVTec says they are not designed to be run with larger Dia SPrings and no spring guide.
 

·
Registered
Joined
·
2,726 Posts
Discussion Starter · #9 ·
Many are doing it. What happened with yours Randy?

I ran 10 lbs last week and had pucks loaded at 147 grams with 800/1300 PB spring and 50/44 beige wrapped to 21 lbs. Was a pretty warm day in the mid 30's F.

Engagement was only like 2400 RPM. Less than 2500 anyway. If your anti-lag is at 3200 and hold there, you'll need clutch engagement up at like 36-3700 if anti-lag holds that exact RPM. Not gonna happen with the PB-80 loaded with weight.

Don't forget your race fuel spiked in there with stock compression!

You will not need anti lag or high engagement on the snow. It's going to be blowing the track away leaving at an idle!
What are the ratings on that PB 800/1300 spring? Also, how much does each PB washer weigh? I can't remember. I have a bunch and some slugs. Sounds like you are in the same boost neighborhood as I am on my trail map.

I'm running The MoTeC set up for 91 octane on my trail map, so race fuel should not be needed. Thanks for your advice.

Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
3,508 Posts
If I remember correctly the 800/1300 is 178-307 measured actual at Doo heights on my spring test. after a few days of use was down to like 165-292 as I recall. Close enough to pass for a new 160-290 brand new Doo spring with no sack on it. I can't find my notebook right now, but those numbers are what I remember.

Those tin pucks weigh from 5.4-5.7 grams each. I use one 54.5 G slug and add small weights from there.

If your limiter is up at 9000 you can run less weight and spin it up higher which will be better too. Take out 10-15 grams per shoe if your limiter is at 9000.

And that 50-44 is a lot of helix for a turbo on the trail too. Generally I'm down in the 47-44 or 48-42 range depending on what conditions are. Would think about a 44-40 if you run less weight and spin higher RPM in the drive clutch to keep more pinch on the belt with less drive weight to keep belt slippage at bay. All depending on traction, gearing, RPM and conditions you're running in.
 

·
Registered
Joined
·
2,726 Posts
Discussion Starter · #11 ·
Mike, you say you have 147 g total weight in your clutch. Are you sure that is correct? If my math is correct, that only equates to nine or 10 washers per puck.

Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
3,508 Posts
Mike, you say you have 147 g total weight in your clutch. Are you sure that is correct? If my math is correct, that only equates to nine or 10 washers per puck.

Sent from my iPhone using Tapatalk
147 grams per shoe total weight, X3 shoes.

Sorry, I think in only one shoe total weight. And I have only 8500 RPM limit so I have to keep it under that. You can be lighter if up at 9000 by 10-15 g per shoe.
 

·
Registered
Joined
·
2,726 Posts
147 grams per shoe total weight, X3 shoes.

Sorry, I think in only one shoe total weight. And I have only 8500 RPM limit so I have to keep it under that. You can be lighter if up at 9000 by 10-15 g per shoe.
Thx Mike. I'm assuming that 147 grams includes the shoe. Sorry for all the questions. I ordered a gram scale online which should be here tomorrow so I can clear all this up.
I have a very similar primary spring as you and I have a slug and 7 washers per shoe right now. Did a quick run last night and need to take out 2-3 washers per shoe. Need about 600 more rpm.

Sent from my iPad using Tapatalk
 

·
ride hard or die trying
Joined
·
7,799 Posts
This past weekend on hard packed snow

3/4 throttle. 8900 rpm 5.5psi

125Grams. Purple spring

21lb Preload. 48/38 helix.

41t gear 185km/h on speedo
Clutchs are cold.( only one 2 inch frog skin in shock tower.

The same set up was showing 8300-8400 the weekend before in soft snow

Mike would you think the 47-44 helix would be good for trails?
 

·
Registered
Joined
·
2,726 Posts
Discussion Starter · #16 ·
This past weekend on hard packed snow

3/4 throttle. 8900 rpm 5.5psi

125Grams. Purple spring

21lb Preload. 48/38 helix.

41t gear 185km/h on speedo
Clutchs are cold.( only one 2 inch frog skin in shock tower.

The same set up was showing 8300-8400 the weekend before in soft snow

Mike would you think the 47-44 helix would be good for trails?
What are the specs on the purple spring?

Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
3,508 Posts
This past weekend on hard packed snow

3/4 throttle. 8900 rpm 5.5psi

125Grams. Purple spring

21lb Preload. 48/38 helix.

41t gear 185km/h on speedo
Clutchs are cold.( only one 2 inch frog skin in shock tower.

The same set up was showing 8300-8400 the weekend before in soft snow

Mike would you think the 47-44 helix would be good for trails?
Andrew,

Depending on conditions, I have been using it and liking it. I've been using a 50-44 for racing, but in loose conditions its a bit too much start, 47-44 has been great on average trails, 48-42 when its a bit looser out, and 48-40 in deeper loose stuff. Real condition dependent, plus I still have that dang 8500 limiter to stay off of.

Cant wait to get that raised up after the season is over!
 

·
Registered
Joined
·
2,726 Posts
Discussion Starter · #20 ·
Lack of snow and dialing in the program have limited my ability to fully dial the clutch in. It's darn near 60 degrees here today. WTF. Right now I'm running 14 disks per puck ( one slug and 4 disks). I've got a 195/295 Dalton spring. Now, I'm still getting the duty cycle figured out w the Motec boost controller, so I'm only up to 6.5 pounds of boost and turning 8750 rpm. I'm sure I'll be removing a disk or two once I'm up at the 10 pound range and colder weather.

Sent from my iPhone using Tapatalk
 
1 - 20 of 23 Posts
Top