Sachs 4 puck- thoughts?

[TheProfessional]

Thanks guys for trying to help. Somedude, did you stay with DMF?

I'm getting confused between these clutches.
So the one i Linked has torque at 810+Nm but that's with DMF. once you go to the SMF it's rated at 600+Nm. Here's where i'm getting my info:https://www.sachsperformance.com/en...ce-clutch/vw-golf-vii-5g1/2-0-r-4motion-221kw

so now i'm confused why is DMF rated higher than SMF. Also what are the advantages/disadvantages of going SMF or DMF then? the only ones I think of are. DMF will be less chatter. DMF might not be up to snuff with power like big turbo,hybrid EQT. But confused why the rating with DMF is higher on their website. another is DMF is heavier with more parts/springs etc so RPM matching downshifting is slower. I would gladly stay with DMF if i know it can withstand stage 3 like power levels, at least i wouldn't have as much chatter. my other options was SB daily (which is at the upper limit of being able toh old stg III power reliably) or endurance(which can hold the power but prone to heating (kevlar lining) if dragging, not that I do that but perhaps occasionally).

Lastly, I really do not understand how a 4puck design (less contact area vs a full faced) can have more holding power??? also do you think it have any longevity to it or will last less than a full faced organic/sintered friction disk? (assuming same driver with 30+ years of experience driving manuals)

I am staying with DMF. Honestly, I think it may be a typo on their website unless they use a pressure plate with less clamping force on the SMF kit.

As for advantages of one or the other: DMF will be quieter at idle and having more mass will make it smoother from a stop and/or require less revs to get moving. SMF has less mass, so it will free rev and drop revs faster. This requires a little more skill to start smoothly and will allow for easier rev matching when changing gears. For ultimate performance, SMF is the better option. Until I plan to shoot for more than 600 ft lbs of torque, I am content with a DMF.

The reason a 4 puck is rated for more are the material differences in the friction surfaces. The coefficient of friction for ceramic is nearly double the coefficient of friction for organic (0.4-0.6 for ceramic vs. 0.25-0.3 for organic). You multiply the clamping force of the pressure plate by the friction coefficient to get the friction force between the disk and flywheel. As long as the friction force is higher than the reactionary force created by the engine torque, it will hold fine.

Additionally, friction force is not a function of area, so theoretically less contact area doesn't make a difference in transmittable torque through a clutch. However, shear stress (which is affected by cross sectional area) is a factor they must consider when design the clutch disk, so they can't make it infinitesimally small.

As far as clutch life, only time will tell. Depends on how you use the car. If it is for spirited daily driving, I suspect it will last a long time. If you are drag racing every weekend, not so much.

Hope that helps.

 

[ZuMBLe]

I'm likely going this route also, but I probably won't exceed 350lb of torque. Hopefully this setup is great for daily/traffic and has good modulation. I could just turn down the boost and let my stock clutch live, but I'm telling myself this clutch upgrade is a reliability and longevity upgrade.

 

[stockton2007]

I'm likely going this route also, but I probably won't exceed 350lb of torque. Hopefully this setup is great for daily/traffic and has good modulation. I could just turn down the boost and let my stock clutch live, but I'm telling myself this clutch upgrade is a reliability and longevity upgrade.

They have a full face organic option also, that will hold 350 ft lbs. Slightly cheaper also and compatible wit the stock DMF

 

[slow12s]

Since the DKM thread went to shit and customer service seems to be non-existant, this is the clutch on the top of my list right now...hopefully still have some life left in my stock clutch, but subscribing for updates/experiences from owners

 

[stockton2007]

Since the DKM thread went to shit and customer service seems to be non-existant, this is the clutch on the top of my list right now...hopefully still have some life left in my stock clutch, but subscribing for updates/experiences from owners

That was my first choice till i couldn't take the chance of having the issues people were having with my daily.

Install date 12/29.

 

[ZuMBLe]

I'd rather pay a bit more for a lot more headroom if the 4 puck behaves as well as I've been told. Launch control and FFS. Haha

They have a full face organic option also, that will hold 350 ft lbs. Slightly cheaper also and compatible wit the stock DMF

 

[nonegiven]

Might not be relevant but here's a similar clutch and DMF review on the BMW platform: https://www.e90post.com/forums/showthread.php?t=753877

 

[dub_guy]

Lastly, I really do not understand how a 4puck design (less contact area vs a full faced) can have more holding power??? also do you think it have any longevity to it or will last less than a full faced organic/sintered friction disk? (assuming same driver with 30+ years of experience driving manuals)

Think about it this way, very simplified: have someone stand on your hand in bare feet, and then stand on your hand in stilettos. Same weight, but applying a higher pressure due to reduced area.


So you can increase grip of the clutch several ways: increase clamping force, increased friction via different materials, reduce area (increase pressure), or increase area (increased friction). Generally increased area can't be done (due to constraints in disk size), which is why twin discs exists as they double area.

 

[TheProfessional]

reduce area (increase pressure), or increase area (increased friction).

No. It is shear, not friction that is effected area. The only way you are increasing friction force is with additional clamping load or higher coefficient of friction. Contact area plays no role in friction force developed between two surfaces.

 

[radoroc]

I'm not sure if this will hold a big turbo upgrade with only a 600nm rating. Hopefully it's a typo.

 

[ZuMBLe]

According to ECS, the Sachs 4 puck is rated at 810nm, which is about 600 lb ft.

I'm not sure if this will hold a big turbo upgrade with only a 600nm rating. Hopefully it's a typo.

 

[dub_guy]

No. It is shear, not friction that is effected area. The only way you are increasing friction force is with additional clamping load or higher coefficient of friction. Contact area plays no role in friction force developed between two surfaces.

I totally acknowledge my incorrect choice of words and accept your correction. Been a long time since I've dealt with those details.

 

[TheProfessional]

I'm not sure if this will hold a big turbo upgrade with only a 600nm rating. Hopefully it's a typo.

That is with the SMF. The 4 puck with DMF is 810 N-m as zumble said. Since they are the same clutch disk, I suspect it is a typo.

 

[Golf7RR]

I am staying with DMF. Honestly, I think it may be a typo on their website unless they use a pressure plate with less clamping force on the SMF kit.

As for advantages of one or the other: DMF will be quieter at idle and having more mass will make it smoother from a stop and/or require less revs to get moving. SMF has less mass, so it will free rev and drop revs faster. This requires a little more skill to start smoothly and will allow for easier rev matching when changing gears. For ultimate performance, SMF is the better option. Until I plan to shoot for more than 600 ft lbs of torque, I am content with a DMF.

The reason a 4 puck is rated for more are the material differences in the friction surfaces. The coefficient of friction for ceramic is nearly double the coefficient of friction for organic (0.4-0.6 for ceramic vs. 0.25-0.3 for organic). You multiply the clamping force of the pressure plate by the friction coefficient to get the friction force between the disk and flywheel. As long as the friction force is higher than the reactionary force created by the engine torque, it will hold fine.

Additionally, friction force is not a function of area, so theoretically less contact area doesn't make a difference in transmittable torque through a clutch. However, shear stress (which is affected by cross sectional area) is a factor they must consider when design the clutch disk, so they can't make it infinitesimally small.

As far as clutch life, only time will tell. Depends on how you use the car. If it is for spirited daily driving, I suspect it will last a long time. If you are drag racing every weekend, not so much.

Hope that helps.

yep, sure does help thanks for the detailed information!!
I think you are very happy with your setup and I am probably going to go the same route if/when my normal RSR get's overwhelmed from my upgrades. just wondering if i could stay with my same DMF (currently at 40k miles plus) and really do not know the condition until it's really opened up and then having to buy one on the spot. sometimes even brand new parts are out of balance. DMF's speaking...i don't like to re-surface things like this either..
does the setup also come with the all metal VAG TOB? or I would buy that separately? thanks again, enjoy!!

 

[Beans1]

I'd be extremely surprised if this clutch is not complete crap for a daily. I've driven many pucked clutches, and have zero desire to drive one in anything but a 100% racing application.

But, i'd love to be proven wrong.