MDS C-1 Turbo Weight open discussion

MDS · Sep 2, 2011

MDS Clucthing started developing clutch weights for Cat turbos last season. Our test sled was a 2009 M8 BD running 8 lbs boost. Our goal was to utilize OEM secondary for better bottom end response in the trees. Mid-season we sent weights out to test riders at various altitudes this thread is for their feedback.

RACINSTATION · Sep 2, 2011

Ill jump in and say that we got a set of test weights early on and I felt they worked great!!! I had to mess around a little bit with the primary spring to get the engagement that I liked. I was running them on a 2011 M8 with 9-10lbs of boost. They seemed to have the properties of a lighter weight down low and then as boost built and rpms increased they worked like a heavy tipped weight.

The nice thing about a turbo is that if you are over or under taching, you can adjust your boost to compensate rather than adding or taking away weight on the hillside. I saw an increase in track speed, about 5mph under full load going up a hill. Was also (which is typical for the MDS weights) able to pull 8-10 grams more weight and achieve the same shift out.

A turbo is a touchy sled to setup because you have so many variables affecting end performance. Fuel, boost, etc all play into a sled running right. If you have a sled that is not running right, don't start throwing money at the problem because it is something wrong with the current setup and you need to correct it first and then go for mo go!

WyoBoy1000 · Sep 2, 2011

I got a hold of a set of these weights and installed them in my 09 twisted m8, the sled was built by twisted and had really responsive clutching to start with and was on the target rpm but the rpm would spike 200 over then level out with good backshift, but the rpms still went up and down 150 non stop.
I wanted to see if these MDS weights where up to the challenge so I took a spare secondary clutch with a stock 36* helix to the hill and found a good hill to do some testing, with the twisted setup I made several pulls to check track speed, rpm, and put some highmarks up. I then changed out the weights right on the spot and installed the MDS weights and stock secondary with a rock rollers and shift assist.
First pull it engaged nicely and right away it felt smoother and had more pull out of the whole. The rpm's where within 50 of the twisted clutching and held within 50rpm once peak rpm was reached, it also did not spike rpm it just climbed up and held. Once on the boost the backshift is near perfect. Belt and clutch temps where way down also, noticeably cooler.

At 10,400ft elevation and 2+ft of pow.
Twisted
Boost --6lbs (6-7lbs is the limit on pump gas with this setup) gt2871-2 turbo
twisted clutching, 7lbs is comparable to a bd pg kit on 8lbs.
track speed -- 42-43mph (even though it seems like low mph it would flat out beat a piped m1000 that says its running 47mph track speed, turbos are just different)
RPM-- 8100 (as close as I could tell)

MDS
Boost -- 6lbs
track speed-- 51-52mph (9mph over twisted clutching)
RPM-- 8050

With the twisted setup I couldn't make the climb, with the MDS setup it went in a straight line up and over. Very impressive.

I tried the twisted secondary (I think it has a 36/44-46* helix) with the MDS weights and had 46-47mph track speed and didn't hold rpm up top as well.
One thing I really liked was when I turned it up to 10lbs of boost I was still in the rpm range and it flat ripped, maybe a little high rpm but still worked, so if I was running rg-pg mix on 10lbs and had to add straight pg my rpm was still in the right range to ride.

everytime5.9 · Sep 2, 2011

What does everyone recommend for the secondary?
Stock?
Shift Assist?
Springs?
What helix for what psi?

WyoBoy1000 · Sep 3, 2011

depends on what year, who's turbo kit, how much boost, elevation, could you be more specific.

WITHERS · Sep 3, 2011

WyoBoy1000 said:
I got a hold of a set of these weights and installed them in my 09 twisted m8, the sled was built by twisted and had really responsive clutching to start with and was on the target rpm but the rpm would spike 200 over then level out with good backshift, but the rpms still went up and down 150 non stop.
I wanted to see if these MDS weights where up to the challenge so I took a spare secondary clutch with a stock 36* helix to the hill and found a good hill to do some testing, with the twisted setup I made several pulls to check track speed, rpm, and put some highmarks up. I then changed out the weights right on the spot and installed the MDS weights and stock secondary with a rock rollers and shift assist.
First pull it engaged nicely and right away it felt smoother and had more pull out of the whole. The rpm's where within 50 of the twisted clutching and held within 50rpm once peak rpm was reached, it also did not spike rpm it just climbed up and held. Once on the boost the backshift is near perfect. Belt and clutch temps where way down also, noticeably cooler.

At 10,400ft elevation and 2+ft of pow.
Twisted
Boost --6lbs (6-7lbs is the limit on pump gas with this setup) gt2871-2 turbo
twisted clutching, 7lbs is comparable to a bd pg kit on 8lbs.
track speed -- 42-43mph (even though it seems like low mph it would flat out beat a piped m1000 that says its running 47mph track speed, turbos are just different)
RPM-- 8100 (as close as I could tell)

MDS
Boost -- 6lbs
track speed-- 51-52mph (9mph over twisted clutching)
RPM-- 8050

With the twisted setup I couldn't make the climb, with the MDS setup it went in a straight line up and over. Very impressive.

I tried the twisted secondary (I think it has a 36/44-46* helix) with the MDS weights and had 46-47mph track speed and didn't hold rpm up top as well.
One thing I really liked was when I turned it up to 10lbs of boost I was still in the rpm range and it flat ripped, maybe a little high rpm but still worked, so if I was running rg-pg mix on 10lbs and had to add straight pg my rpm was still in the right range to ride.

So WYO are you now running the stock Cat secondary or have you got the Twisted setup dialed in now.

WyoBoy1000 · Sep 3, 2011

I ran the 36* stock helix for a while then got an adjustable helix for it but pretty much I have been running the stock secondary with shift assist and harder rollers, but that was the clutch off my m1000 and I sold it so I just put the twisted secondary that was on the sled back on and it works, never really needed more after the snow got firmer.

One thing I did do is get my secondary clutches rebuilt, if the bushing wear out it will cause all kinds of problems(bad performance, ruin motor mounts, ruin belts) it will fell like its powering out. One thing I have seen is if you have any clutch problems at all the MDS weights will show it right away, you have to make sure the clutches are in good conditions and properly setup or after installing MDS weights you wont see the performance increase you should.

yamazoom · Sep 19, 2011

I installed a set of MDS turbo clutch weights on my 2010 M8 Boondocker race gas turbo in February and wanted to give an update as to my experience with both the weights and the owner Steve. To start out with, Steve has been there to answer my emails and phone calls in a very prompt manner. He set me up with a base setting and helped me with adjustments and changes as I ride at 9-11,000 ft. When I ran the base settings that Steve recommended the top end pull was amazing, track speed picked up approximately 7 mph over a setup that I was extremely happy with. The one drawback to this setup was a loss of bottom end response. I made a phone call to Steve and we talked through the setup, a decision was made to move some weight out of the tip and in to the middle. I made the change and went to the mountain. This was the setup I was looking for, bottom end was crisp and rippy like a stocker, but with the top end pull of a turbo. My track speed was still 5 mph faster as compared to my old setup. Belt and clutch temps were amazingly cooler and the boondocking capabilities are so much better. I tested with a stock 36 degree helix and found that between 7 and 9 pounds of boost it worked great, above 9 pounds of boost it seemed as though the engine wanted more helix as it would over rev. I installed a 34/42 helix cut by Black Diamond and found I had an even bigger improvement to my bottom end while the more aggressive top angle helped control the RPM’s at the top. I’ve ran other turbo weights in the past and found that you give up something in throttle response either in the low or mid, with the tune ability of the MDS weights you give up nothing but gain in the low, mid, and high RPM’s. I run my boost at 9 psi most of the time and turn it up to 13 psi on big snow days. I do not have to add or remove weight with this setup, it just pulls harder. Just my 2cents on a great product.

WyoBoy1000 · Sep 20, 2011

On bigger boost depending on elevation you may need different helix options, I think racinstation has down quite a bit of testing with good results for different boost levels.

I could run from 6-11lbs and stay in a good rpm range, I went to 13.3 once and it was a little over but still worked (75-80mph track speed at 10000ft), I think with a little more weight it would add performance but it was putting a big load on the stock 36* helix.

Ski-Laxn · Sep 23, 2011

I was going to put my opinion in on the weights. But yamazoom said it so well that all I will do is agree with him. I feel that when it comes to clutching it is all personal. But the starting point is with MDS weights.

Vertical-Extreme · Sep 27, 2011

so has anyone ran them at 12-14 lbs of boost on an M8? if so what helix? cause it sounds like the 36* might not be enough for the higher boost levels

WyoBoy1000 · Sep 27, 2011

I ran up to 13.3lbs with the 36* but I can't say for sure because I had other problems. I broke a cross bar in the track and you could feel and hear it clicking/thunking, with the kmod you have to run the track pretty tight and with the broken cross bar even tighter keep it from ratcheting, which put a huge load on my clutching. At 10000ft I was above 75mph (at least 75mph, it was hard to watch) track speed, but felt a little slow getting there, which could be from the track tightness or the fact I had straight av gas in it, you can really feel it slow down on straight av, I found I could run 12lbs with 2 gallons of av with a lot better response. I had also borrowed a secondary from a friend that day (stock 2010 m8 secondary) I had my 36* on my m1000 and let someone use it and they didn't tighten the secondary down and broke off a bunch off the helix screws and ruined a bunch of stuff. I think between the high boost, busted track and ratcheting it blew apart the stock 2010 rollers and ruined the clutch, that weekend cost me a lot of money.

The specifics of the MDS weights will depend on the sled ( ie from 09 to '10 changed a lot) it will also depend on the turbo kit, rider style and boost level. I believe you can see gains with any kit and mds weight. If your asking what happens at 12-14lbs you could probably install the MDS weights and see the same performance of your previous setup at 10lbs.

At 10000ft running over 10lbs I would prob go with a 36/40* or straight 39* or 40*, at least thats where I would start. The twisted helix I have (I think its a 36/44 or 46*) works well on 12lbs but I think there is a little more track speed to be had dropping down to a 40, considering I'm at 10000ft. I have not tried a straight angle helix yet.

Vertical-Extreme · Sep 28, 2011

The whole MDS turbo weight theroy kind of reminds me of Kevin (mmsports)'s turbo clutching. you use a specific turbo profile weight to load the turbo instread of using a reverse cut helix, and with this weight you can use a straight helix and stock secondary spring. I would be interested to see how the two compared.

RACINSTATION · Sep 28, 2011

I ran a 39 helix on mine with higher boost numbers 12-15psi.

WyoBoy1000 · Sep 28, 2011

RACINSTATION said:
I ran a 39 helix on mine with higher boost numbers 12-15psi.

What elevation

Going West · Oct 14, 2011

I just ordered a set of these weights for the new PC 800. Ill be running some where between 12 and 14 lbs of boost.

I ride between 4 and 7000 feet.

I was going to buy a coulple of different helixs to try and was wondering what would be some good angles to try. I was thinking a straight 38 and maybe a 36/40 or 34/40.

All sugesstions and thoughts are welcome.

yamazoom · Oct 15, 2011

On my 2010 M8 at 10K feet I found the straight 36 degree helix worked very good up to 8-9 psi. I found that beyond that the motor wanted to over rev. I tryed variations of helix from straight 40, 36/46, and 34/44. The 40 worked great at the top end but lacked on the bottom for boondocking, the 36/46 worked well but the high finish angle dropped my top end rpm too much. The last helix 34/44 increased the throttle response at the bottom more that the stock helix but maintained the pull and constant rpm all the way up. All of this testing was at higher boost, 13 psi. The 34/44 is what I stayed with through the rest of the season and really liked it in all conditions from boondocking to hill climbing.

Going West · Oct 15, 2011

Instead of running a multi angle helix to controll all the over rev, couldn'y you just run some more weight in the primary, and sick with a straight helix???

yamazoom · Oct 16, 2011

Going West said:
Instead of running a multi angle helix to controll all the over rev, couldn'y you just run some more weight in the primary, and sick with a straight helix???

I've tested this both ways, In my opinion and for my riding style I chose to move a little weight from the tip to the middle keeping overall weight the same. This will increase throttle response in the trees and overall boondocking. If you prefer more point and shoot, load the tip of this weight and run a straight helix such as the stock 36. I found more overall track speed with this setup but I chose to sacrifce 2 mph track speed for near instant boost. I think it really comes down to riding style and rider preference.

sweperformance · Oct 17, 2011

I run a 34/44 bikeman torsional conversion setup with heavy hitters primary weights. The rpm is stable and good in all conditions, but in deep powder and full trottle, it feels like i`m not getting enough trackspeed. It weels better when decresing spring tension. Any suggestions?

The sled is a push turbo M8 2008, 10lbs of boost, 210hp in dyno. Top rpm, 7800-7900rpm.

yamazoom said:
On my 2010 M8 at 10K feet I found the straight 36 degree helix worked very good up to 8-9 psi. I found that beyond that the motor wanted to over rev. I tryed variations of helix from straight 40, 36/46, and 34/44. The 40 worked great at the top end but lacked on the bottom for boondocking, the 36/46 worked well but the high finish angle dropped my top end rpm too much. The last helix 34/44 increased the throttle response at the bottom more that the stock helix but maintained the pull and constant rpm all the way up. All of this testing was at higher boost, 13 psi. The 34/44 is what I stayed with through the rest of the season and really liked it in all conditions from boondocking to hill climbing.

MDS C-1 Turbo Weight open discussion

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