Just had the Motordrive limited slip differential fitted so thought I'd better see what it could do. Spent a few hours at Bedford autodrome playing on their slippery skid-pan area this morning.
Great fun, and I'm sure that this isn't possible without an LSD fitted. Thanks to both Tess Tickle and Karel for suggesting the LSD as an essential upgrade for the Cayman..
A couple of quick videos of a Cayman playing in the wet... before using it for what it's intended for.
A limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In an automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity.
The main advantage of a limited slip differential is found by considering the case of a standard (or "open") differential where one wheel has no contact with the ground at all. In such a case, the contacting wheel will remain stationary, and the non-contacting wheel will rotate freely– the torque transmitted will be equal at both wheels, but will not exceed the threshold of torque needed to move the vehicle, thus the vehicle will remain stationary. In everyday use on typical roads, such a situation is very unlikely, and so a normal differential suffices. For more demanding use however, such as driving off-road, or for high performance vehicles, such a state of affairs is undesirable, and the LSD can be employed to deal with it. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels.
To see the installation of a LSD style unit Click Here -> Article Forthcoming Stay Tuned
Motordrive
Motordrive
Moslo Mill
Ebury Street
Radcliffe
Manchester
M26 4BL
UK
Nice! Definitely the one essential upgrade for the CS.
Didn't know they had a skid pan at Bedford! Where is that and how do you get on it?
Were all the track videos you too? Who was the passenger?
It's supposed to be an activity area for the Caterhams on the corporate days but we hired it from MSV directly for a few hours. Really good fun, no supervision and left to just play for the morning. If anyone is interested in talking to MSV about booking a session there let me know and I'll send some contact details.
They're are a lot of circuit videos some where me and some the instructor I had for the day. You can tell mine as I'm the slow one; the silver snail
Maybe I should hire the venue...at least everybody could "Get a little knowledge and feel" for what the diff is capable of before they go on track....or the road.
You can be very assured that was not me driving Tess Tickle.. I could only go round 3/4 of a time before forgetting where I was going
It was all throttle and steering with no PSM brake engagement. Leave PSM on and it was just about impossible to get any slide before the car took control.
Still smiling this morning.
Steven
PSM - Porsche Stability Management
While it can’t overcome the laws of physics, the revolutionary Porsche Stability Management (PSM) system does lend an added degree of balance and control to the Cayman’s mid-engine driving dynamics, inspiring surefooted confidence in corners and extreme situations.
A standard feature on the Cayman and Cayman S, PSM continuously monitors steering input, road speed, yaw velocity and lateral acceleration to calculate the actual direction of travel. If the car begins to steer off line, PSM instantly intervenes with precision brake inputs on individual wheels to help bring the car back onto the driver’s intended path.
If braking alone isn’t enough to correct the vehicle’s cornering line, PSM then calls on the Cayman’s engine management system, adjusting engine output as needed to help stabilize handling. PSM can also compensate in an instant for mid-corner changes in load resulting from deceleration or braking. When Sport mode is selected with the optional Sport Chrono Package, PSM’s threshold for intervention is raised, allowing for greater driver involvement. If you prefer driving without automatic PSM assistance, the system can be set to standby at any time. In this case, it will only intervene under heavy braking, where both front wheels exceed the ABS threshold.
For all of its technical ability, PSM goes virtually unnoticed in everyday driving situations, preserving the Cayman’s natural agility.
So who is Braduke2K that posted your drifting video wit comments attached? Very confused
There are 2 other vids with someone that looks like an instructor driving. One around the GP circuit and one around the East(?) circuit. Who was the instructor, and was he any good? Did you get much out of the experience?
"Nice! Definitely the one essential upgrade for the CS."
I disagree, a nice mod but not an essential mod.
yes, in the wet or power on tight turns on track or doing stuff like skid pan fun.
But on the road with PS2's on I don't want for a LSD and I drive it fast.
if it does get lose in the damp you can still power slide the Cayman with no LSD.
I have a fast road geo without silly camber settings and have so much grip I never spin an inside wheel anyway, Also I don't get the slight push a LSD can give.
A limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In an automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity.
The main advantage of a limited slip differential is found by considering the case of a standard (or "open") differential where one wheel has no contact with the ground at all. In such a case, the contacting wheel will remain stationary, and the non-contacting wheel will rotate freely– the torque transmitted will be equal at both wheels, but will not exceed the threshold of torque needed to move the vehicle, thus the vehicle will remain stationary. In everyday use on typical roads, such a situation is very unlikely, and so a normal differential suffices. For more demanding use however, such as driving off-road, or for high performance vehicles, such a state of affairs is undesirable, and the LSD can be employed to deal with it. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels.
To see the installation of a LSD style unit Click Here -> Article Forthcoming Stay Tuned
Tire Rack
Tire Rack is your one stop shop for Tires, Wheels, Suspension components and other Cayman accessories. Please Click This Link to make a purchase and the PlanetPorsche.Net site will receive a commission.
__________________
Save the cheerleader save the world
There should be a load more videos on youtube not just 2 though. The two from the other day were one of me and one of him.. he's the neat one going round in rectangle shaped patterns. The ones from within the car are quite fun but just make me dizzy watching them.
Brad is a friend of mine who works at Bedford as an instructor.. Any good.. I'm not in a position to judge, he's faster than me by a long shot but there again so are most people His best time on the GT circuit in the Cayman is 2.48 before the LSD where is mine is 3.05..
He's coming up to Silverstone in August to have a go in the Cayman around that circuit.
Steven the snail signing-off...
LSD - Limited Slip Differential
A limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In an automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity.
The main advantage of a limited slip differential is found by considering the case of a standard (or "open") differential where one wheel has no contact with the ground at all. In such a case, the contacting wheel will remain stationary, and the non-contacting wheel will rotate freely– the torque transmitted will be equal at both wheels, but will not exceed the threshold of torque needed to move the vehicle, thus the vehicle will remain stationary. In everyday use on typical roads, such a situation is very unlikely, and so a normal differential suffices. For more demanding use however, such as driving off-road, or for high performance vehicles, such a state of affairs is undesirable, and the LSD can be employed to deal with it. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels.
To see the installation of a LSD style unit Click Here -> Article Forthcoming Stay Tuned
Mrd, I don't think I have ever met anyone as confrontational as you
Of course no mod is essential, just as no option is essential. But, having had my car for 3 years and (almost) 7 months and 52000 miles, I still stand by my original statement that this is the first, and only, mod I will have on my car. My diff gets used every single day, in the wet and the dry. I find one of its main benefits is how the PSM intervention in tight, low speed corners, and at junctions in particular, is pushed out a considerable notch.
PSM - Porsche Stability Management
While it can’t overcome the laws of physics, the revolutionary Porsche Stability Management (PSM) system does lend an added degree of balance and control to the Cayman’s mid-engine driving dynamics, inspiring surefooted confidence in corners and extreme situations.
A standard feature on the Cayman and Cayman S, PSM continuously monitors steering input, road speed, yaw velocity and lateral acceleration to calculate the actual direction of travel. If the car begins to steer off line, PSM instantly intervenes with precision brake inputs on individual wheels to help bring the car back onto the driver’s intended path.
If braking alone isn’t enough to correct the vehicle’s cornering line, PSM then calls on the Cayman’s engine management system, adjusting engine output as needed to help stabilize handling. PSM can also compensate in an instant for mid-corner changes in load resulting from deceleration or braking. When Sport mode is selected with the optional Sport Chrono Package, PSM’s threshold for intervention is raised, allowing for greater driver involvement. If you prefer driving without automatic PSM assistance, the system can be set to standby at any time. In this case, it will only intervene under heavy braking, where both front wheels exceed the ABS threshold.
For all of its technical ability, PSM goes virtually unnoticed in everyday driving situations, preserving the Cayman’s natural agility.
Mrd - I'd seen your video on Youtube shortly after uploading our ones.. fantastic control and a lot more challenging than playing in a open area with not a lot to hit.
Jack - Free instruction, do you guys need it? Although I'm sure if anyone is interested in going around with Bradley he'd be only too happy to help. I know he's working at Silverstone in a couple of weeks so should be pretty familiar with the circuit.
Tess Tickle - Have you got your confirmation yet or are they still holding out on you?
as for psm i run in sport mode 100% of the time which gives you a bigger slip angle, with a good geo you don't need a LSD on the road imho.
My car is set up for fast road use and as I say do not spin an inside wheel.
I did with my old set up and bridgestones, but with my new Geo and PS2's its
got enough grip by far not to need one.
I am not confrontational just have my own opinions :-( I find it odd you want a LSD so much but will not get a remap which rids the car of the nasty 3.5k dead spot.
As for instruction i am always up for that.
LSD - Limited Slip Differential
A limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In an automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity.
The main advantage of a limited slip differential is found by considering the case of a standard (or "open") differential where one wheel has no contact with the ground at all. In such a case, the contacting wheel will remain stationary, and the non-contacting wheel will rotate freely– the torque transmitted will be equal at both wheels, but will not exceed the threshold of torque needed to move the vehicle, thus the vehicle will remain stationary. In everyday use on typical roads, such a situation is very unlikely, and so a normal differential suffices. For more demanding use however, such as driving off-road, or for high performance vehicles, such a state of affairs is undesirable, and the LSD can be employed to deal with it. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels.
To see the installation of a LSD style unit Click Here -> Article Forthcoming Stay Tuned
PSM - Porsche Stability Management
While it can’t overcome the laws of physics, the revolutionary Porsche Stability Management (PSM) system does lend an added degree of balance and control to the Cayman’s mid-engine driving dynamics, inspiring surefooted confidence in corners and extreme situations.
A standard feature on the Cayman and Cayman S, PSM continuously monitors steering input, road speed, yaw velocity and lateral acceleration to calculate the actual direction of travel. If the car begins to steer off line, PSM instantly intervenes with precision brake inputs on individual wheels to help bring the car back onto the driver’s intended path.
If braking alone isn’t enough to correct the vehicle’s cornering line, PSM then calls on the Cayman’s engine management system, adjusting engine output as needed to help stabilize handling. PSM can also compensate in an instant for mid-corner changes in load resulting from deceleration or braking. When Sport mode is selected with the optional Sport Chrono Package, PSM’s threshold for intervention is raised, allowing for greater driver involvement. If you prefer driving without automatic PSM assistance, the system can be set to standby at any time. In this case, it will only intervene under heavy braking, where both front wheels exceed the ABS threshold.
For all of its technical ability, PSM goes virtually unnoticed in everyday driving situations, preserving the Cayman’s natural agility.
Tire Rack
Tire Rack is your one stop shop for Tires, Wheels, Suspension components and other Cayman accessories. Please Click This Link to make a purchase and the PlanetPorsche.Net site will receive a commission.
__________________
Save the cheerleader save the world
Well, I've never noticed a dead spot at any revs, wheras the inside rear spinning up is obvious at every junction and bend (especially off camber corners). So it was a no-brainer for me. And I have run PS2s and fast road geo from day one, so I know that neither of those are a factor to the problem I persieved before the TBD.
I think it's great having your own opinion, but I find that that can very often be given without directly questioning someone elses....
TBD - Torque Biasing Differential
With an ordinary open differential, a lot of precious power is wasted during wheel spin under acceleration. This happens because the open differential shifts power to the wheel with less grip, along the path of least resistance. The torque capacity of the TBD/ATB unit is increased or decreased by varying the helix and pressure angles of the gear teeth. The operation is automatic and the unit is a direct replacement with the stock differential. There are no clutch plates as in more conventional limited-slip designs.
The Torque Biasing Differential or A.T.B., however, does just the opposite. It senses which wheel has better grip, and biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel. In drag-race style, straight-line acceleration runs, this results in a close to ideal 50/50 power split to both drive wheels, resulting in essentially twice the grip of an ordinary differential.
To see the installation of a TBD style unit Click Here
Glad you have found ways to get around your percieved deficiencies in your car. I'm quite happy about the action I took to get around mine. End of.
As for this 3.5k "issue": when exactly are you ever operating in this "dead spot"? On the track? Never. On the road? Well that would depend how hard you are pushing. If you are pushing hard, then again, never. If you're not, then what does it matter?
BTW in case you misinterpreted what I was saying, I've had the diff fitted for 18 months already. I don't "want" it, I already have it.
One thing that I deffinitely respect about JW is how he sticks to his guns, particularly in terms of modding. It's a rare man who can claim to have "only" installed an ATB, and it shows someone who's only interested in driving his car, rather than make it faster.
Not that making it faster is bad, I do it myself. Just a different philosophy. You see a mid-range flat-spot that should be removed, he sees a mid-range flat-spot that should be avoided. Different viewpoints.
TBD - Torque Biasing Differential
With an ordinary open differential, a lot of precious power is wasted during wheel spin under acceleration. This happens because the open differential shifts power to the wheel with less grip, along the path of least resistance. The torque capacity of the TBD/ATB unit is increased or decreased by varying the helix and pressure angles of the gear teeth. The operation is automatic and the unit is a direct replacement with the stock differential. There are no clutch plates as in more conventional limited-slip designs.
The Torque Biasing Differential or A.T.B., however, does just the opposite. It senses which wheel has better grip, and biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel. In drag-race style, straight-line acceleration runs, this results in a close to ideal 50/50 power split to both drive wheels, resulting in essentially twice the grip of an ordinary differential.
To see the installation of a TBD style unit Click Here
It's true man, the only person I know who thinks like you is a dear friend of mine, who's currently working for JLR and specializes in chasis dynamics and fuzzy logic. He drives extremely well, and never mods anything, ever. Though, by his own admission, the only mod he'd ever do to a CS would be an ATB.
See, it's a viewpoint thing: You want to perform the absolute utmost the car is capable of from the box, as it is. Others feel they have to help the "latent potential" out of their cars.
The ATB is slightly different in that it's not so much a Mod, as it is an option it should have had from stock. Not so much an improvement as a radical change.
Now having brown-nosed you inadvertedly, I must note that I'm much more inclined to MrD's style of automotive ownership: That tiny dip in torque kills the Engine Tester inside me. Even though it's irrelevant when driving. Its very existence gnaws at my soul, until I got a SRP.
Thankfully I won't need an exhaust, as I value NVH over performance and there's practically none to be had in the 2.7 anyway.
TBD - Torque Biasing Differential
With an ordinary open differential, a lot of precious power is wasted during wheel spin under acceleration. This happens because the open differential shifts power to the wheel with less grip, along the path of least resistance. The torque capacity of the TBD/ATB unit is increased or decreased by varying the helix and pressure angles of the gear teeth. The operation is automatic and the unit is a direct replacement with the stock differential. There are no clutch plates as in more conventional limited-slip designs.
The Torque Biasing Differential or A.T.B., however, does just the opposite. It senses which wheel has better grip, and biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel. In drag-race style, straight-line acceleration runs, this results in a close to ideal 50/50 power split to both drive wheels, resulting in essentially twice the grip of an ordinary differential.
To see the installation of a TBD style unit Click Here
SRP
SRP = Softronic Race Plenum, a plenum available from Softronic, see their website www.softronic.us for more details.
I know this is a long lived thread (mid June)... couple of points
1) I am surprised that the CS didn't come w/ LSD stock... my '95 Z28 came w/ it (yeah, yeah... not apples to apples)
2) I doubt w/ the PSM that any "real world" driving would NEED the LSD... (if I were towing a boat up a wet ramp, then yes)
3) Looks to me like Mrd was getting his b@lls busted for just speaking his mind.
4) I'm a "noob" to the CS, but noticed the "dead spot" straight away... just put the car in 2nd or 3rd and floor it... the sudden jolt of speed you feel is AFTER the dead spot... same 3.5K location... it must be a valve timing thing??? w/ the variable ratio... (I'm totally guessing w/ that tho).
Everyone's got an opinion... take it or leave it... no worries.
JT
LSD - Limited Slip Differential
A limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In an automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity.
The main advantage of a limited slip differential is found by considering the case of a standard (or "open") differential where one wheel has no contact with the ground at all. In such a case, the contacting wheel will remain stationary, and the non-contacting wheel will rotate freely– the torque transmitted will be equal at both wheels, but will not exceed the threshold of torque needed to move the vehicle, thus the vehicle will remain stationary. In everyday use on typical roads, such a situation is very unlikely, and so a normal differential suffices. For more demanding use however, such as driving off-road, or for high performance vehicles, such a state of affairs is undesirable, and the LSD can be employed to deal with it. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels.
To see the installation of a LSD style unit Click Here -> Article Forthcoming Stay Tuned
PSM - Porsche Stability Management
While it can’t overcome the laws of physics, the revolutionary Porsche Stability Management (PSM) system does lend an added degree of balance and control to the Cayman’s mid-engine driving dynamics, inspiring surefooted confidence in corners and extreme situations.
A standard feature on the Cayman and Cayman S, PSM continuously monitors steering input, road speed, yaw velocity and lateral acceleration to calculate the actual direction of travel. If the car begins to steer off line, PSM instantly intervenes with precision brake inputs on individual wheels to help bring the car back onto the driver’s intended path.
If braking alone isn’t enough to correct the vehicle’s cornering line, PSM then calls on the Cayman’s engine management system, adjusting engine output as needed to help stabilize handling. PSM can also compensate in an instant for mid-corner changes in load resulting from deceleration or braking. When Sport mode is selected with the optional Sport Chrono Package, PSM’s threshold for intervention is raised, allowing for greater driver involvement. If you prefer driving without automatic PSM assistance, the system can be set to standby at any time. In this case, it will only intervene under heavy braking, where both front wheels exceed the ABS threshold.
For all of its technical ability, PSM goes virtually unnoticed in everyday driving situations, preserving the Cayman’s natural agility.
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