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01-14-2015, 10:21 AM | #111 | |
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01-14-2015, 10:23 AM | #112 | |
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the e46 has a gkn viscolok like the e92. completely different technology. |
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01-14-2015, 03:35 PM | #113 | |
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The E39 M5 is the ZF clutch LSD with 2 clutches. You can put 4 clutches if the thickness of the clutches and steel plates are less than stock. |
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01-14-2015, 08:11 PM | #114 | |
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Question, by variable ramp angle, do they mean that there are different lock up rates under acceleration and deceleration like a 1.5 way Kaaz? Or does it refer to being able to customize the ramp angle(s)? A steeper ramp angle means quicker lock up?
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01-15-2015, 03:12 AM | #115 | |
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With OS giken it's the other way around. With ZF LSD (210mm diffsonline for example), an angle of 30/90 means that the LSD is 1 way: 30 angle on acceleration means that it will lock less progressively than 45 degree stock (the end locking is the same though, that depends on the clutches, friction material, etc ...) 90 degrees on deceleration means that the LSD will not do anything when decelerating since the 90 degrees angle will be blocking the spider gears support from engaging the clutches and hence will be an OPEN diff. Stock is 45/45 which is a very neutral and safe. Diffsonline can also do a variable ramp 30/60/90 and drexler can do a curve ramp instead of a straight line: a 30/60/90 is a 1 way diff that on acceleration will initially have a less aggressive lockup pattern and after arriving to a higher degree of slip the diff will still be locking up progressively but at a more aggressive pace as the slip becomes greater. (it could be also the opposite, depending on how the LSD is machined and what the race driver wants the car to behave like) This kind of variable ramp can only provide a benefit for a very very skilled driver as he will need to be able to pull off special driving tactics like entering a corner and rotating the car with the LSD benefitting from the progressively aggressive lockup. Now to images: This is a 55/90 on the right and 45/20 This is the link and image for example: |
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01-15-2015, 05:09 AM | #116 |
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the steeper the ramps, the quicker and smoother it reacts!
the more shallow the ramps are, the more lockup is generated. the aim should always be to put in as many clutchpacks as possible and have the ramps as steep as possible. "variable ramps" are no option in professional lsd building as in a properly configured lsd, the axles will travel no more than 1-2mm at highest! machining a curve that makes sense and can be driven properly without the lsd doing unpredictable things is not possible. don't buy units with "variable" ramps! drexler doesn't do that either if you look at there pressure plates in detail. the part where the axles travel up and down is a stright line... the curves are done on the upper part of the "V" where the axle will never move to (maybe because it looks better or the plate gets more stable or it simply is easier to machine like that?!) if diffsonline really means that when talking about "variable ramps" i'd like to see a closeup of their ramps! if they mean you can choose what ramp they should use it would make more sense but then they need to manufacture and harden each set individually what also makes no sense. if they mean it is no 2-way but 1.5 or 1 way they use the wrong words! so i would really be interested what they want us to say with "variable ramps"?! |
01-15-2015, 07:08 AM | #117 |
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Thanks for the spot on answers!!!
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01-15-2015, 07:57 AM | #118 | |
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This is a far better explanation than mine. I missed the point where the diff actually pushes on the ramp and this is how the locking mechanism is actuated. For the variable ramps you can see here as this is my reference: http://www.zpost.com/forums/showpost...0&postcount=22 This is my friend with a supercharged track weapon 4.10 diff Z4M. |
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01-15-2015, 02:26 PM | #119 | |
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01-15-2015, 03:55 PM | #120 | |
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he also speaks about 90% lockup? with 2 clutchpacks?! hmmm... besides the fact, that 90% lockup is way too much in nearly any racing situation i can think of, he has the first lsd out there that does this with just 2 clutchpacks. anyway: i would still be very interested in more details about the "30/60/90 ramps". a picture of these ramps would be perfect. |
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01-15-2015, 03:58 PM | #121 |
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01-16-2015, 02:02 AM | #122 | |
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Help us out here What do you mean by variable ramp angles? Do you think you can get a picture from dan ? |
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01-16-2015, 09:13 AM | #123 | ||
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Or am I way off???
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01-16-2015, 09:14 AM | #124 | ||
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01-16-2015, 09:27 AM | #125 | ||
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01-16-2015, 09:42 AM | #126 | |
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i still do not understand how a "mechanical ramp" is capable of "30/60/90". you mean 30/60/90 is the percentage of torque difference of the two drivewheels until the lsd opens? or what is this "30/60/90" thing? what does it describe or stand for? and when does it "30", when "60" und when "90"? i struggle to understand it if we take physical laws as given and even diffsonline is not able to go beyond these laws ;-) |
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01-16-2015, 09:52 AM | #127 | ||
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01-16-2015, 09:53 AM | #128 | |
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so if you have a lsd without a belleville spring that was built with the right assembly clearance this is ok if you will have it rebuilt on a regular basis. i also like to build racesetups without springs but with some preload generated from the clutches themselves. if you measure this setup you will also have a certain amount of preload but if you open it, there is no belleville spring inside. these are the quickest reaction setups out there. there are so many tweaks you can tune a clutch type lsd. each one has certain pros and cons. |
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01-16-2015, 10:07 AM | #129 | |||||
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so it simply makes no sense to give different percentage values. it does make sense to give two values as there is one ramp for power and one for coast. but a third ramp simply is not there! of course the guys at diffsonline can claim anything they want to. but as long as there is no in depth explanation to this "magical behaviour", i can not believe it. Quote:
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...but in what situation will this unit lock 60%? |
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01-16-2015, 10:26 AM | #130 | ||||||
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01-16-2015, 10:42 AM | #131 | |
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the more lockup, the more the drive wheels tend to be connected together. both wheels spinning with the same speed means the car pushes straight. on decel, more lockup results in a more stable rear end. this is why a (good) 911 setup always has more lockup on decel. even a 2 way lsd feels to lock harder on power because if you think of the torques applied under hard acceleration vs. hard braking ;-) so the M3 GT4 (or Z4 GT3 MJ2011) bmw factory lsd units had more lockup (via more shallow ramps) on decel to get a real 2-way "feeling". anyway: if you like your setup the way it is, this is perfect! how it was actually done or what exact setup you do have is of no importance for you. my interest in the setup of a certain diff (re-)builder and how he does his setups is not so high that i will contact and ask them. i discussed with matt monson of guard transmission a while ago. quite interesting in some points but i do not agree with him in all points. but he definitely knows what he is doing! i also discussed with other such diff-builders a few years ago... which often ended that i explained how it works and how it is done better. now i simply do it myself. ;-) i think it is more helpful for me to talk to the technical contacts of the lsd manufacturers, some amg and bmw motorsports engineers as well as companies providing the most important parts like lsd clutch manufacturers, ... (most of them are based in europe, what makes it easier for me). these companies do a lot of research (some more, some less) and you get first hand information on what works and what doesnt (or works, but not as good as it could). |
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01-16-2015, 10:51 AM | #132 | ||
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