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#2445966 - 02/03/18 09:20 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: lockjaw-express]
moparpoolman Offline
enthusiast

Registered: 11/27/06
Posts: 319
Loc: NE
All the info so far is great, Thanks, But Back to the original question, Car is a 4000lb 68 Plymouth b body, 18 Spline A833 with a Centerforce II Pressure Plates CFT361800 with an original steel flywheel and a 384071 Clutch Disc, 420HP to the rear tires(slicks) with a 4.10 Dana that I don't drive on the street? From the info so far I'm thinking I need to get away from the Centerforce and a different Disc.
Sounds like I need a clutch that's going to slip some to not shock the car so bad. Do I NEED an adjustable clutch or is there a NON adjustable clutch that would be good for my above application? What Disc to use? What Flywheel to use? Thanks again


Edited by moparpoolman (02/05/18 04:19 PM)
Edit Reason: added clutch info

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#2445977 - 02/03/18 09:37 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
madscientist Offline


Registered: 09/17/14
Posts: 1953
Loc: Washington
Originally Posted By moparpoolman
All the info so far is great, Thanks, But Back to the original question, Car is a $4000 68 Plymouth b body, 18 Spline A833 with a centerforce clutch, 420HP to the rear tires(slicks) with a 4.10 Dana that I don't drive on the street? From the info so far I'm thinking I need to get away from the Centerforce and a different Disc.
Sounds like I need a clutch that's going to slip some to not shock the car so bad. Do I NEED an adjustable clutch or is there a NON adjustable clutch that would be good for my above application? What Disc to use? What Flywheel to use? Thanks again


ADJUSTABLE CLUTCH.
SINTERED IRON DISC.
ALUMINUM FLYWHEEL.

You can call Hyatt, the guy in Idaho whose name I can't think of right now, McLeod, Black Magic Clutches just to name a few can hook you up.

You need to be able to adjust the clutch.

Also, it's not so much that the clutch slips. It's more correctly termed engagement. You need to control how fast the disc catches up to speed with the flywheel and pressure plate. Slipping the clutch is a bad way to describe it.
_________________________
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston

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#2446007 - 02/03/18 10:45 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: madscientist]
GomangoCuda Offline


Registered: 01/21/03
Posts: 3460
Loc: N.E. Ohio
Quote:
the guy in Idaho whose name I can't think of right now


That would be Rob Youngblood, owner of Advanced Clutches.

http://www.advancedclutches.com/metalcoverclutches.htm

NOTE: There is a similar named company at advancedclutch.com that sells ricer stuff. Don't go there.tsk You might catch some exotic asian disease. laugh2


Edited by GomangoCuda (02/03/18 10:55 PM)
_________________________
Van Roy's Law: An Unbreakable Toy Is Useful For Breaking Other Toys.

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#2446028 - 02/03/18 11:14 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: GomangoCuda]
madscientist Offline


Registered: 09/17/14
Posts: 1953
Loc: Washington
Originally Posted By GomangoCuda
Quote:
the guy in Idaho whose name I can't think of right now


That would be Rob Youngblood, owner of Advanced Clutches.

http://www.advancedclutches.com/metalcoverclutches.htm

NOTE: There is a similar named company at advancedclutch.com that sells ricer stuff. Don't go there.tsk You might catch some exotic asian disease. laugh2



Yup. Rob Youngblood. Do know why I couldn't think of that.
_________________________
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston

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#2446049 - 02/04/18 12:20 AM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
perfmachst Offline
member

Registered: 09/02/10
Posts: 170
Loc: renton , washington
the softloc, will slip enough to let you use aluminum flywheel , even on street! a rag disc and more pressure does not!! mcloed flat said, aluminum flywheel only, the cluch gets hot and will grab so hard and be very jerky. there's a reason why they want you to use their setup. less problems and comebacks. all my cars have had aluminum flywheel on the street, had no problems driving them. even had one behind a 265 chev in 55 chev. with a 3000# clutch!! very old school back then , 1965. like anything else, you learn how to make it work correctly.

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#2446313 - 02/04/18 01:52 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
weedburner Offline


Registered: 10/21/14
Posts: 45
Loc: Washington
Originally Posted By moparpoolman
After seeing the "Soft Lok Thread", I didn't want to hijack so started a new one.
I keep breaking the 18 spline A833, blow all the teeth off third gear on the cluster. Broke 3 in the last 8 years only going to the track about 5 times a year. Car is a 68 Plymouth b body, A833 with a centerforce clutch, 420HP to the rear tires with a 4.10 Dana that I don't drive on the street?
Is an adjustable clutch my answer? What other adjustable clutches like a McLeod Soft Lok are available? The "clutchtamer"
http://clutchtamer.com/
sounds interesting, anyone run one?
I'm wondering what I should do?? Different disc? get away from the cenerforce and go with a regular Ram or Mcleod? switch to an adjustable clutch? or maybe try a clutchtamer with it the centerforce??? The more I research it the more confused I'm getting, HELP?


A SoftLoc style clutch isn't likely to be any easier on your 3rd gear than the Centerforce. The basic problem with both is that they hit their hardest after a WOT shift. That's just a function of them using centrifugal assist as a part of their overall clamp load. The SoftLoc's iron disc makes it even worse as it grabs harder as it gains temperature. If your 833 still has synchros, forget about hi rpm powershifts with that heavy full face iron disc.

Another thing to keep in mind is that going to a lighter flywheel doesn't affect how HARD a clutch hits, it only affects how LONG it can maintain that hard hit.

No need to buy an expensive lightweight clutch. You'll get better results at your power level with a simple ClutchTamer softening the hit of a RAM Powergrip HD. Far less maintenance, no need for a hole in the bellhousing, and more efficient than a SoftLoc style adjustable clutch. I doubt there's a more cost effective way to improve your 60' while softening the hit on your drivetrain at the same time.

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#2446868 - 02/05/18 11:55 AM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: weedburner]
moparpoolman Offline
enthusiast

Registered: 11/27/06
Posts: 319
Loc: NE
Originally Posted By weedburner
Originally Posted By moparpoolman
After seeing the "Soft Lok Thread", I didn't want to hijack so started a new one.
I keep breaking the 18 spline A833, blow all the teeth off third gear on the cluster. Broke 3 in the last 8 years only going to the track about 5 times a year. Car is a 68 Plymouth b body, A833 with a centerforce clutch, 420HP to the rear tires with a 4.10 Dana that I don't drive on the street?
Is an adjustable clutch my answer? What other adjustable clutches like a McLeod Soft Lok are available? The "clutchtamer"
http://clutchtamer.com/
sounds interesting, anyone run one?
I'm wondering what I should do?? Different disc? get away from the cenerforce and go with a regular Ram or Mcleod? switch to an adjustable clutch? or maybe try a clutchtamer with it the centerforce??? The more I research it the more confused I'm getting, HELP?


A SoftLoc style clutch isn't likely to be any easier on your 3rd gear than the Centerforce. The basic problem with both is that they hit their hardest after a WOT shift. That's just a function of them using centrifugal assist as a part of their overall clamp load. The SoftLoc's iron disc makes it even worse as it grabs harder as it gains temperature. If your 833 still has synchros, forget about hi rpm powershifts with that heavy full face iron disc.

Another thing to keep in mind is that going to a lighter flywheel doesn't affect how HARD a clutch hits, it only affects how LONG it can maintain that hard hit.

No need to buy an expensive lightweight clutch. You'll get better results at your power level with a simple ClutchTamer softening the hit of a RAM Powergrip HD. Far less maintenance, no need for a hole in the bellhousing, and more efficient than a SoftLoc style adjustable clutch. I doubt there's a more cost effective way to improve your 60' while softening the hit on your drivetrain at the same time.


The 833's I'm running do not have synchros. One is a "slick shift" and one is a "Liberty pro shift"
What is the best way to be shifting? WOT? Pressing clutch? Tapping clutch? No Clutch?

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#2446895 - 02/05/18 12:36 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
cuda499 Offline
member

Registered: 02/02/13
Posts: 45
Loc: Canada
Originally Posted By moparpoolman
All the info so far is great, Thanks, But Back to the original question, Car is a $4000 68 Plymouth b body, 18 Spline A833 with a centerforce clutch, 420HP to the rear tires(slicks) with a 4.10 Dana that I don't drive on the street? From the info so far I'm thinking I need to get away from the Centerforce and a different Disc.
Sounds like I need a clutch that's going to slip some to not shock the car so bad. Do I NEED an adjustable clutch or is there a NON adjustable clutch that would be good for my above application? What Disc to use? What Flywheel to use? Thanks again


Weird that you blew up the trans before the centerforce clutch blew up.... I blew my center force before the trans let go, it use to just smere the clothe side, 550 whp.. I always ran an alum flywheel but had to lauch it fairly high... like 6000+ rpm. car has stock 833 23 spline. I would def try an alum flywheel or else just order a soft lock from chris hyatt. IF your interested I have his number you can PM me.

*from my experience, I would guess that an alum flywheel and a centerforce clutch would prob solve the issue but I could be wrong....

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#2446910 - 02/05/18 12:57 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
perfmachst Offline
member

Registered: 09/02/10
Posts: 170
Loc: renton , washington
Originally Posted By moparpoolman
Originally Posted By weedburner
Originally Posted By moparpoolman
After seeing the "Soft Lok Thread", I didn't want to hijack so started a new one.
I keep breaking the 18 spline A833, blow all the teeth off third gear on the cluster. Broke 3 in the last 8 years only going to the track about 5 times a year. Car is a 68 Plymouth b body, A833 with a centerforce clutch, 420HP to the rear tires with a 4.10 Dana that I don't drive on the street?
Is an adjustable clutch my answer? What other adjustable clutches like a McLeod Soft Lok are available? The "clutchtamer"
http://clutchtamer.com/
sounds interesting, anyone run one?
I'm wondering what I should do?? Different disc? get away from the cenerforce and go with a regular Ram or Mcleod? switch to an adjustable clutch? or maybe try a clutchtamer with it the centerforce??? The more I research it the more confused I'm getting, HELP?


A SoftLoc style clutch isn't likely to be any easier on your 3rd gear than the Centerforce. The basic problem with both is that they hit their hardest after a WOT shift. That's just a function of them using centrifugal assist as a part of their overall clamp load. The SoftLoc's iron disc makes it even worse as it grabs harder as it gains temperature. If your 833 still has synchros, forget about hi rpm powershifts with that heavy full face iron disc.

Another thing to keep in mind is that going to a lighter flywheel doesn't affect how HARD a clutch hits, it only affects how LONG it can maintain that hard hit.

No need to buy an expensive lightweight clutch. You'll get better results at your power level with a simple ClutchTamer softening the hit of a RAM Powergrip HD. Far less maintenance, no need for a hole in the bellhousing, and more efficient than a SoftLoc style adjustable clutch. I doubt there's a more cost effective way to improve your 60' while softening the hit on your drivetrain at the same time.


The 833's I'm running do not have synchros. One is a "slick shift" and one is a "Liberty pro shift"
What is the best way to be shifting? WOT? Pressing clutch? Tapping clutch? No Clutch?
only way to shift a proshift trans is at WOT. if driving around slowly, then double clutch to up shift and down shift. trans will not grind. the ratio of Z bar will dictate how you use the clutch. I could tap mine, but my Z bar ratio was changed to do that. you do have to use the clutch. BTW, the softloc does slip on gear change, which softens the hit, that's way it was designed to operate. the pressure is less at lower rpm. I know it's not as hard as a 1600# clutch with rag disc hits. also, I don't have C/W on my softloc. also, as mcloed guy said, it fools the engine, has a convertor behind it. the RPM drop is less, because the clutch does slip some, as RPM comes up , it locks up.

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#2446916 - 02/05/18 01:06 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
68LAR Offline
master

Registered: 10/10/03
Posts: 3732
Loc: South Park, Pa.
Originally Posted By moparpoolman
Originally Posted By weedburner
Originally Posted By moparpoolman
After seeing the "Soft Lok Thread", I didn't want to hijack so started a new one.
I keep breaking the 18 spline A833, blow all the teeth off third gear on the cluster. Broke 3 in the last 8 years only going to the track about 5 times a year. Car is a 68 Plymouth b body, A833 with a centerforce clutch, 420HP to the rear tires with a 4.10 Dana that I don't drive on the street?
Is an adjustable clutch my answer? What other adjustable clutches like a McLeod Soft Lok are available? The "clutchtamer"
http://clutchtamer.com/
sounds interesting, anyone run one?
I'm wondering what I should do?? Different disc? get away from the cenerforce and go with a regular Ram or Mcleod? switch to an adjustable clutch? or maybe try a clutchtamer with it the centerforce??? The more I research it the more confused I'm getting, HELP?


A SoftLoc style clutch isn't likely to be any easier on your 3rd gear than the Centerforce. The basic problem with both is that they hit their hardest after a WOT shift. That's just a function of them using centrifugal assist as a part of their overall clamp load. The SoftLoc's iron disc makes it even worse as it grabs harder as it gains temperature. If your 833 still has synchros, forget about hi rpm powershifts with that heavy full face iron disc.

Another thing to keep in mind is that going to a lighter flywheel doesn't affect how HARD a clutch hits, it only affects how LONG it can maintain that hard hit.

No need to buy an expensive lightweight clutch. You'll get better results at your power level with a simple ClutchTamer softening the hit of a RAM Powergrip HD. Far less maintenance, no need for a hole in the bellhousing, and more efficient than a SoftLoc style adjustable clutch. I doubt there's a more cost effective way to improve your 60' while softening the hit on your drivetrain at the same time.


The 833's I'm running do not have synchros. One is a "slick shift" and one is a "Liberty pro shift"
What is the best way to be shifting? WOT? Pressing clutch? Tapping clutch? No Clutch?



I still can't see why you are breaking 18 spline transmissions with your horsepower. Doing a burnout in first, second or third has nothing to do with breaking third gear. Clutch types only affect the launch. Once you get moving and into second gear, all clutches are grabbing hard. Very little slippage, if any at all. If you're breaking third gear with a 400+ hp engine, you got something else going on and it ain't the clutch.
I run a slick shifted 18 spline with syncro's. You need to use the clutch to shift. I power shift it at 6000 with no issues. I have shifted it as high as 6500. Seeing no difference in time slips, I went back to the 6000 rpm shift points. I ran a pro shifted 18 spline for a time. Didn't like it much on the street. It also needed to be shifted with a clutch. My car is very simular in weight to yours, but with a 600+hp stroker 440.
I run an 11" Centerforce DFX with an aluminum flywheel. I don't break my tranny's????????? Like I've said before, I must be just lucky after 50 years of driving my car..

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#2447242 - 02/05/18 10:53 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
GTX MATT Offline
master

Registered: 06/05/06
Posts: 4796
Loc: CT
Hey bud, you break last time out? I don't think you're going to do much better switching to McLeod or Ram non-adjustable. They're all pretty similar coefficient of friction/static pressure to hold similar power. My Ram Powergrip HD is like a dump truck clutch.

I think if you go adjustable with an aluminum flywheel you at least have a chance to improve your 60 ft too. Coming out at 5 grand will be easier on your trans. You can switch to a Ram adjustable setup pretty cheap, and if its a stock flywheel I would change the flywheel to a billet one anyway. That thing is taking a beating for a 50 year old cast piece, don't want that coming apart even with the scattershield.


Edited by GTX MATT (02/05/18 10:56 PM)
_________________________
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street

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#2447383 - 02/06/18 11:42 AM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
GTX MATT Offline
master

Registered: 06/05/06
Posts: 4796
Loc: CT
Do you still have the over-center spring on the clutch pedal?
_________________________
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street

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#2447413 - 02/06/18 12:38 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: GTX MATT]
moparpoolman Offline
enthusiast

Registered: 11/27/06
Posts: 319
Loc: NE
Originally Posted By GTX MATT
Do you still have the over-center spring on the clutch pedal?

NO

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#2447426 - 02/06/18 12:55 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: perfmachst]
weedburner Offline


Registered: 10/21/14
Posts: 45
Loc: Washington
Originally Posted By perfmachst

BTW, the softloc does slip on gear change, which softens the hit, that's way it was designed to operate. the pressure is less at lower rpm. I know it's not as hard as a 1600# clutch with rag disc hits. also, I don't have C/W on my softloc. also, as mcloed guy said, it fools the engine, has a convertor behind it. the RPM drop is less, because the clutch does slip some, as RPM comes up , it locks up.


Adjustables typically play on the difference between shift rpm and fallback rpm. At shift rpm they are at maximum clamp pressure, but as the clutch pulls engine rpm down they reach a point where they lose enough centrifugal assist that the clutch begins to slip a significant amount. This raises the fallback rpm some, which adds a little hp.

The actual hit after a wot shift with a SoftLoc is not softened at all.

On 10.5" Long PP geometry, the stock cw levers alone still add about 500-600lbs of centrifugal clamp @ 6k even without any added counterweight...



Bump that shift rpm up to 8k with your right foot flat on the floor, those stock cw levers, without any extra weight added, still add over 1000lbs to the base clamp load.


Edited by weedburner (02/06/18 12:58 PM)

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#2447935 - 02/07/18 08:37 AM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: weedburner]
moparpoolman Offline
enthusiast

Registered: 11/27/06
Posts: 319
Loc: NE
Thanks for responses, interesting graph, amazing how the clamping load increases so much from 6000 to 8000 but I am running a rev limiter set at 6200 and shift at 5600 and never hit the limiter during shifts.
We only heard from a few different guys so far, like to hear more from others that aren't breaking of what clutches they are running?????and if they were happy or not with their setup?

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#2447966 - 02/07/18 09:41 AM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
fourgearsavoy Offline


Registered: 12/07/04
Posts: 9201
Loc: Rittman Ohio
My last clutch when I was racing the car was an old Hays MK12 adjustable and they weren't very easy on the drive train. I had it set at 1200 for the track and 2000 for street driving. I used a RAM bronze disc and that probably saved the transmission because once it glazed over they slipped pretty good. I never ran bigger than a 9" tire with 833's or a Richmond 5-speed with face-plate gears.
Now I don't race it much anymore so I am running a CF2 with a Mcleod 500 series dual friction clutch disc.
If I race it again I probably will only use DOT street slicks so it doesn't hook so hard twocents

Gus beer
_________________________
64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60

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#2448324 - 02/07/18 11:25 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: moparpoolman]
GTX MATT Offline
master

Registered: 06/05/06
Posts: 4796
Loc: CT
Do many people run an adjustable pressure plate without a sintered iron disc?

Does anyone think something like the 6 puck Rametallic with a lighter pressure plate might work for the OP? Anyone know what kind of static load you're supposed to run with those?
_________________________
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street

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#2448357 - 02/08/18 02:22 AM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: GTX MATT]
weedburner Offline


Registered: 10/21/14
Posts: 45
Loc: Washington
Here's some very general calculated torque capacities per 1000lbs of clamp pressure for typical "10.5" clutch discs (actually around 10.375" dia od friction material)...

organic- 180ftlbs
dual friction- 276ftlbs
ceramic- 293ftlbs
iron- 289ftlbs

From those numbers if a 440 made 600ftlbs, here's the minimum amount of clamp required to hold the torque for various friction materials...

organic- 3334 lbs
dual friction- 2175 lbs
ceramic- 2048 lbs
iron- 2076 lbs

With the typical adjustable you are trying to slip as much as you can off the line without slipping too much in high gear. An organic disc is going to limit what you can do as it loses cof as it gains temperature. Ceramic is a pretty much the same compound as a ceramic brake pad, heat doesn't really change cof much. Iron does exactly what you want as it gains cof as you work thru the gears, which widens your tuning window.

From the above you can also see why ceramic has such a bad reputation for being like an "off/on switch". They are typically paired with a pressure plate suited to hold an organic disc, when they should be paired with a pressure more like that for an iron disc.









Edited by weedburner (02/08/18 02:23 AM)

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#2448656 - 02/08/18 04:29 PM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: 68LAR]
cuda499 Offline
member

Registered: 02/02/13
Posts: 45
Loc: Canada
Originally Posted By 68LAR
Originally Posted By moparpoolman
Originally Posted By weedburner
Originally Posted By moparpoolman
After seeing the "Soft Lok Thread", I didn't want to hijack so started a new one.
I keep breaking the 18 spline A833, blow all the teeth off third gear on the cluster. Broke 3 in the last 8 years only going to the track about 5 times a year. Car is a 68 Plymouth b body, A833 with a centerforce clutch, 420HP to the rear tires with a 4.10 Dana that I don't drive on the street?
Is an adjustable clutch my answer? What other adjustable clutches like a McLeod Soft Lok are available? The "clutchtamer"
http://clutchtamer.com/
sounds interesting, anyone run one?
I'm wondering what I should do?? Different disc? get away from the cenerforce and go with a regular Ram or Mcleod? switch to an adjustable clutch? or maybe try a clutchtamer with it the centerforce??? The more I research it the more confused I'm getting, HELP?


A SoftLoc style clutch isn't likely to be any easier on your 3rd gear than the Centerforce. The basic problem with both is that they hit their hardest after a WOT shift. That's just a function of them using centrifugal assist as a part of their overall clamp load. The SoftLoc's iron disc makes it even worse as it grabs harder as it gains temperature. If your 833 still has synchros, forget about hi rpm powershifts with that heavy full face iron disc.

Another thing to keep in mind is that going to a lighter flywheel doesn't affect how HARD a clutch hits, it only affects how LONG it can maintain that hard hit.

No need to buy an expensive lightweight clutch. You'll get better results at your power level with a simple ClutchTamer softening the hit of a RAM Powergrip HD. Far less maintenance, no need for a hole in the bellhousing, and more efficient than a SoftLoc style adjustable clutch. I doubt there's a more cost effective way to improve your 60' while softening the hit on your drivetrain at the same time.


The 833's I'm running do not have synchros. One is a "slick shift" and one is a "Liberty pro shift"
What is the best way to be shifting? WOT? Pressing clutch? Tapping clutch? No Clutch?



I still can't see why you are breaking 18 spline transmissions with your horsepower. Doing a burnout in first, second or third has nothing to do with breaking third gear. Clutch types only affect the launch. Once you get moving and into second gear, all clutches are grabbing hard. Very little slippage, if any at all. If you're breaking third gear with a 400+ hp engine, you got something else going on and it ain't the clutch.
I run a slick shifted 18 spline with syncro's. You need to use the clutch to shift. I power shift it at 6000 with no issues. I have shifted it as high as 6500. Seeing no difference in time slips, I went back to the 6000 rpm shift points. I ran a pro shifted 18 spline for a time. Didn't like it much on the street. It also needed to be shifted with a clutch. My car is very simular in weight to yours, but with a 600+hp stroker 440.
I run an 11" Centerforce DFX with an aluminum flywheel. I don't break my tranny's????????? Like I've said before, I must be just lucky after 50 years of driving my car..


X2 on trans shouldn't be breaking

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#2449011 - 02/09/18 04:26 AM Re: Adjustable or Non-adjustable Clutch Advise Needed [Re: weedburner]
DGS Offline
mopar

Registered: 07/08/05
Posts: 491
Loc: Graz, Austria
Originally Posted By weedburner
Here's some very general calculated torque capacities per 1000lbs of clamp pressure for typical "10.5" clutch discs (actually around 10.375" dia od friction material)...

organic- 180ftlbs
dual friction- 276ftlbs
ceramic- 293ftlbs
iron- 289ftlbs

From those numbers if a 440 made 600ftlbs, here's the minimum amount of clamp required to hold the torque for various friction materials...

organic- 3334 lbs
dual friction- 2175 lbs
ceramic- 2048 lbs
iron- 2076 lbs

With the typical adjustable you are trying to slip as much as you can off the line without slipping too much in high gear. An organic disc is going to limit what you can do as it loses cof as it gains temperature. Ceramic is a pretty much the same compound as a ceramic brake pad, heat doesn't really change cof much. Iron does exactly what you want as it gains cof as you work thru the gears, which widens your tuning window.

From the above you can also see why ceramic has such a bad reputation for being like an "off/on switch". They are typically paired with a pressure plate suited to hold an organic disc, when they should be paired with a pressure more like that for an iron disc.



ok, so if I would do all clutch slipping with the pedal the "ideal" clutch setup would be a pressure plate that has just enough base pressure to not slip at idle and added counterweight pressure that follows the torque curve throughout the rpm range.
Well, since the added counterweight pressure usually can't follow the torque curve perfectly (centrifugal pressure increases exponentially whereas the torque curve usually has more of a logarithmic shape) you start with a higher base pressure and add less centrifugal pressure, correct?

In my case I have a McLeod B&B/Long PP (360951) with 2400lbs base pressure and counterweights. If I would use an organic disc I need roughly 1000 lbs of centrifugal pressure at the rpm I hit 600 ft/lbs of torque (let's say at 4000rpm) for the clutch not to slip (2400 base + 1000 = 3400 pressure). At 6000rpm the centrifugal pressure is more than double that at 4000rpm which is not really necessary as the torque increase between both points is only a few ft/lbs.
Would I be better off if I lower the base pressure and centrifugal assist (less or no counterweights) and run a disc with a higher friction coefficient than an organic disc?

This only takes into account going through the rpm range without shifting (where you don't want your clutch to slip).
When shifting you want some slippage though - otherwise shifts are too violent (at least for a street car). So is a dual friction disc the solution in a street car? It would have some slippage when shifting but a much higher cof (less base and centrifugal pressure needed).

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Trouble with oil leaks in a 440
by Frankenduster
Today at 03:04 AM