CVT test run

[JohnF]

I bothered a cvtech engineer for about a week digging into this stuff for my clutch.
Go here to the CVTech R&D home page. Under "Technical Information" select "Pulley Adjustment" and there will be a choice that gives "Spring Specs".
I don't know the invance secondary but i imagine there are spring choices.

Shoot a query to info@cvtech-aab.com - I got a technical rep. named David and he will help.

And I think you mean to decrease the primary spring preload but keep the same rate.

Does your drive pulley have the cool mass blocks with the disk masses and screw cap? Probably. Lucky...
And which primary spring do you have?

[EDIT]

Hey, I found a post of yours where you describe the tune being sluggish until 2500-2800 RPM. I think you are describing lugging. Increase the preload in the secondary so it stays in a lower gear longer. Like I said above - it should engage - go to 3600** (oops, that's my target RPM) RPM - and then start shifting up.

** - If you hunt around under "Pulley Adjustment" there is another "Pulley Adjustment" that shows a curve. Ignore the exact numbers. Imagine an ideal curve that has a straight line from engagement RPM to max HP RPM. This line is steep and the vehicle speed is following granny gear up to max HP RPM. Then the ideal curve is perfectly horizontal as the gearing shifts out. Then at max shift out another steep line as you are fully shifted and now the vehicle speed will increase with engine RPM and the CVT can no longer regulate engine RPM.

If you are feathering the throttle because you are driving around sanely you won't see a lot of this. That's why you need some WOT runs.

[thebuggyman1]

Hey, I found a post of yours where you describe the tune being sluggish until 2500-2800 RPM. I think you are describing lugging. Increase the preload in the secondary so it stays in a lower gear longer. Like I said above - it should engage - go to 3600** (oops, that's my target RPM) RPM - and then start shifting up.

** - If you hunt around under "Pulley Adjustment" there is another "Pulley Adjustment" that shows a curve. Ignore the exact numbers. Imagine an ideal curve that has a straight line from engagement RPM to max HP RPM. This line is steep and the vehicle speed is following granny gear up to max HP RPM. Then the ideal curve is perfectly horizontal as the gearing shifts out. Then at max shift out another steep line as you are fully shifted and now the vehicle speed will increase with engine RPM and the CVT can no longer regulate engine RPM.

If you are feathering the throttle because you are driving around sanely you won't see a lot of this. That's why you need some WOT runs.

The "sluggish" upshift I described was with the rubber engine mounts, and probably incorrectly described. The motor has never lugged or bogged. I think what was happening was the center to center of the clutches was decreasing upon acceleration. Slow start, then sudden upshift(leap in speed) when the mounts flexed, then return to normal upshift as the mount stabilized.

I don't know the code(s) of my spring(s).....I'll have to pull the clutches apart to find that out.
I think I need to do some more testing, hill climbing, trailer towing etc.
So, who wants to ride?

BTW There's lots of good info at that link.

[thebuggyman1]

Power Bloc Clutch Weights

I've put some more time on the machine, tried a few things, and even put it to the torture test IMG_0014.jpgIMG_0015.jpg
There's nothing like taking a 600# machine and towing around a 1200# machine with it.
It was interesting to see the difference in how the clutches shifted.

I also had a nice long chat with Roy @ QDS...most of what he said was way over my head, but the gist is that I needed lighter weights in the primary.
We talked a little about the adjustable type weights, but the range is too small until you get close to the right weight.

My clutch started out with the largest weights they make, 275g... really they weigh 312g, the 275 is just the steel insert not counting the plastic holder.
Roy felt I would need weights about 100g lighter to bring the RPM range to what I wanted. Because the tuning is a trial and error method, I decided to modify the weights I have and hopefully I'll only have to buy the final set at the proper weight.IMG_0017.jpg This afternoon I took the weights to my buddy's machine shop and removed a little steel from them. They now weigh 238g,
that's approx 3/4 of the original weight. WISH ME LUCK

[hydromike]

I'm going to be running the same clutch on the v1505 in the Newt the Bold, but I'm still at the drivetrain layout stage; R&D with clutch engagement is a long way off for me. Nevertheless, it's great to see somebody else toying with the engagment of these clutches to evaluate their sensitivity. I'm probably going to want first engagement around 1100 rpm in mine, especially if I get the range box working the way I want it to.

Definitely keep us updated....
Good luck!

[thebuggyman1]

Gave the lightened clutch weights a test run last night. With the snow in the yard it was hard to tell for sure, but it seemed to change the "fully shifted" RPM by about 200.
I think the full shift was happening at 3k-3100 rpms, and now it seems to happen closer to 3200 or so. My target RPM is closer to 4k-4200, so it's back to the machine shop tomorrow to remove some more weight.
[IMG][/IMG]

[whipper-ag]

[thebuggyman1]

I milled some more weight off today and gave it a try. I started out with weights @ 312g, tried 238g, and today tried 194.5g. Why the "odd" trial weights? It's because it can take several tries on the mill to get them all the same...by the time they are all within 1/2 gram, that's what I got.
The test run today went very well. Upshift was slow, began around 3000 rpm (where I was fully shifted) and seemed to finish around 4300 rpm. This is just a bit more than I had planned, but it tells me what I should buy. Hopefully I can buy 200g weights that will accept the additional discs.
This is a bit confusing Cvtech R&D - - Caractristiques des blocs
I'll just call Roy again Monday

[thebuggyman1]

After the last trial run I decided to add a little more weight back on. That's when it hit me...Why not make the added weight adjustable? So I drilled and tapped a 1/4-20 hole in the center of each weight. I used a grade 8 bolt, 2 washers and a lock washer to bring the weight back to 208 grams. This time I ran the machine down the paved road looking for as little rolling resistance as possible. The clutches seemed to be fully shifted at around 4300 rpm. This is very similar to the lighter weights (194g).
I think I can live with the 4300 rpm, and I think it may change a little when the spring is changed anyway. So, I guess I'll keep it at this weight for now.
The digital tach made reading the rpm very hard, so I ordered a nice analog one. I can reevaluate when I get it installed. IMG_0026.jpgIMG_0025.jpg
To recap for reference purposes, here is some info on weights available from an Argo dealer. Compliments of Mudbug and this thread http://www.6x6world.com/forums/argo-...html#post92243
Optional weights are:

1 127-208 Weight Set (3), 185g - High Elevation....+37g = 222 grams

1 127-209 Weight Set (3), 220g - High Elevation...+37g = 257 grams

1 127-210 Weight Set (3), 240g - High Elevation...+37g = 277 grams

And the standard 275 gram. These are the values of the insert blocks, so for a total weight you have to add the 37 grams of the plastic slider. 275g + 37g = 312 grams

[amphibious drew]

Jim I like the idea of adjustable weight. Is it possible to move the adjustable weights up and down to control engagements? If the majority of weight was on the bottom of the weight or closer to the center of the clutch, would it prevent the clutch from up shifting as quickly as a stock set up? I suspect moving the weight will make as much of a difference as increasing or reducing the weight. Maybe a combination of both would make for the perfect low torque high speed combination on a machine.

[thebuggyman1]

The slider blocks really don't slide...it's more of a rocking action. I did have the same thought, but more along the lines of making sure the weight was taken off the blocks evenly.
I think the weight would have more of an effect if it was on the end that tips, but would be harder to predict.

[Noel Woods]

Good work on working towards the weight issue puzzle. Another example of an amphib owner with skills working to solve a problem. Where are the engineers when they are needed?
Every time an issue like this comes up it pushes me more towards hydraulic power. A pump with direct drive will eliminate the clutches entirely.
Great work on the clutches Jim.

[Bazooo guy]

If you are trying to lower the engagement RPM i think you should be adding weight to the primary .
Or reduce the spring pressure

[thebuggyman1]

If you are trying to lower the engagement RPM i think you should be adding weight to the primary .
Or reduce the spring pressure

The PowerBloc clutches work a little differently than the old comets. The springs have 2 ratings, NM @ engagement, and NM @ fullly shifted (I forget their terms). My spring is rated at 600nm/900nm. Yes, the spring pushes back against the advance of the weights, but primarily it is sized for the initial engagement. Cvtech R&D - - Ajustement des poulies
Tech info from CVTech says to size the weights first then move to the spring.
I'm hoping that by documenting my trials and errors, I can save someone else a few steps in the future.

[Bazooo guy]

I have been trying to figure out how to lower the shift point on my clutch.
When I have a heavy load of wood on my back rack or pulling a trailer with a passenger
it takes a lot longer to upshift.
But when I ride alone without any load the upshift happens much quicker.
The rpm is around 5500 to 6000 when it shifts in both cases.
Im interested to see how adjusting the primary weights effects your shift point.
I love R&D ....keep us posted

[thebuggyman1]

I did a few more test runs yesterday with the new analog tach installed...
I was surprised how accurate the cheap little digital tach was, even though it can be a little hard to read with the numbers changing.
I also tried changing the belt tension, and found out what a big difference that can make. With the belt too tight (3/4" or so deflection), it lowered the fully shifted RPM to about 4k.
With it too loose (1 1/4"), it allowed the primary to close farther at the start before the machine moved, making a more jerky takeoff. I finally settled on about 1 1/16" deflction.
The real test will be this weekend at the Bundy Hill ride.