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LSD Anyone? (Discussion Only)

89K views 454 replies 92 participants last post by  pethier7 
#1 · (Edited by Moderator)
#2 ·
See thread http://www.planet-9.com/showthread.php?t=7526 Item #16

(I have sent both a 3.2 Boxster S diff and a 3.4 Cayman S diff down to Quaife today to see if a) they already have a unit that will slot in or b) so they can measure up to make one. So hopefully by tomorrow I will know. And will keep the club informed on progress should anybody else want to go down that road.)

I'm Expecting a price <£1000 but will post update as soon as I know more information
 
#3 ·
I put the Farnbacher Loles torsen type LSD in the car back in late September. Honestly? In regular around town driving I don't notice much, if any difference. Perhaps on really cold mornings (the PS2 tires on the car seem really, really warm blooded) I'll find the car squealing the rear tires on a right or left turn leaving a stop sign or light, and feel a slight "catch" as the LS does its business. But I can't say I personally feel a huge change in ordinary day to day driving.

I have managed two HPDE days since the install ~ unfortunately, other than noting that my rear pocket feels a bit lite, I guess my blue denim rear end dyno isn't calibrated finely enough to give you an "absolute" "This is da Bomb" endorsement without having another car to do a side by side driving comparison. There were no other Caymans at the HPDE's I could do arrange to try to do a side-by-side with, and frankly the WMB M3's in the run group I was in, just didn't put up much of a fight :)

To really expound on the differences, I think one would need to have two cars, one with, the other without the LSD available to swap into, back and forth to give the list any really relevant or accurate feed back. I think I do hear some occasional clunks etc. from the diff engaging or slipping on really tight, slow turns etc. It's been snowing here some the last couple of weeks, but I only have the OEM Michelin Pilot PS2's on the car. They're so pathetic in the cold on snow, that no amount of slip, limited or otherwise is going to provide any real feedback. I guess I should have tried getting more seat time in the car on the track before the limited slip went in.

I can say, that I have had the chance to do a "side-by-side" LSD comparison in another kind of car ~ two of the older Audi S4/6's I had a '93 S4 with a "locking" rear diff vs. a 95 Audi S6 Avant wagon with the latter model "electronic" differential control. We swapped the rear diff in the S6 wagon for a 1991 Audi V8 torsen mechanical rear diff and ran both cars at the Steamboat winter driving facility (read extreme slipping & sliding) in several Gruppe-Q events. The verdict there was the addition of the V8 torsen rear diff in the Avant wagon, had the Avant running circles around the 93 S4/6 sedan, even with the locking diff in the back. There's some video of the driving conditions etc. under which the testing was done available at www.gruppe-q.com

HTH mike
 
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#4 ·
Thank you for your input. I tracked the car once and with my "jam it out of the corners" style of driving the wheelspin was seriously limmiting my track time. I am sure the LSD will help me because of my style. I did not have this problem with my old '79' 930 turbo. You could jam the throttle hard leaving the turn and shoot out of there like a raped ape. I miss that feeling and that oil smelling thing. The CS is faster though in every other way.

Mike
 
#5 ·
When three Cayman’s and one 997 recently had a run over a relatively notorious road in the Peak District of England. (Cat and Fiddle) All 3 Cayman’s were “lighting” their PASM lights up like Christmas tree’s and obviously losing power, speed and drivability out of corners. The alternative was to switch PASM off, but this only led to spinning the inside rear wheel.
This is the first time in twelve months of ownership that I have really noticed that under these specific circumstances the car needs a diff (LSD), but under said circumstances boy does it need one….so it’s gonna have one !!!!!

I remember in the 80’s dropping one into a 944 and it totally transformed the car…(ok I started going through rear tyres like they didn’t cost real money, but it was awesome) . As most of the capable drivers I know say to me “sideways is NOT the Fast way !!”…but hell it’s the fun way and for sure I love the fun way.:crazy: :crazy: :crazy:
 
#9 ·
I will be very interested to hear the response from Quaife. I mailed them last night to ask if they had any plans for a diff for the Cayman S. So far I have had no reply.

Looking at their on line shop they are asking £750 for their diffs to fit other Porsche models, which seemed pretty reasonable. Of course you have to pay someone to fit it.

If one is made available for the Cayman S, I will give it serious consideration. I will check with Porsche to see if there are any warranty issues. I can't imagine there would be, but it is best to check.
 
#10 ·
Charles
There appears to be 2 threads on the same topic, one under Cayman Competition and one under Cayman Modifications look at the other one::) as I posted last night some more info on the Quafe Diff

http://www.planet-9.com/showthread.php?p=89984#post89984

If your in a position to send them your box complete they will also fit and pre-load the diff for approx £125.00 (problem is the 2 week turnaround !!!)

It looks like their new number for the diff will be QDF12Q, but this has to be confirmed as at the moment it also looks like the price will be £750ish but they want me to order 30 units, to make sure it happens!!!!!! don't suppose you've got 20k doing nothing in your back pocket..have you :) :)
 
#11 ·
dont just put an LSD on your car.
figure out why you need it.
if you drive on street, even if you drive recklessly, you DONT need LSD. it either make you understeer too much or its presence is not felt, money wasted.

if you AX, you most likely need torsen.

if you track, DE, or race, you need plate type. torsen wont work if you lift wheel off ground and that's what happens if you are in the tight turn on track.

if you are spinning inside rear tire (when the tire is on the ground) you need stickier rubber. cayman s at 295hp shouldn't be spinning rear inside tire if it's on dry pavement with good rubber (notice, i said ON the pavement) if you are lifting tires, you need plate type.

grossly simplified, yes, but this is the gist of it.
 
#13 ·
dont just put an LSD on your car.
figure out why you need it.
if you drive on street, even if you drive recklessly, you DONT need LSD. it either make you understeer too much or its presence is not felt, money wasted.

if you AX, you most likely need torsen.

if you track, DE, or race, you need plate type. torsen wont work if you lift wheel off ground and that's what happens if you are in the tight turn on track.

if you are spinning inside rear tire (when the tire is on the ground) you need stickier rubber. cayman s at 295hp shouldn't be spinning rear inside tire if it's on dry pavement with good rubber (notice, i said ON the pavement) if you are lifting tires, you need plate type.

grossly simplified, yes, but this is the gist of it.
If that is the case, just wondering why BMW put them all their M-Cars? And most motoring press regard the lack of LSD the biggest ommission from the Cayman?

Jack
 
#14 ·
If that is the case, just wondering why BMW put them all their M-Cars? And most motoring press regard the lack of LSD the biggest ommission from the Cayman?

Jack
i dont know which type of lsd is in m cars. most m cars are grossly underbuilt as i have had quite of few of them.

plate type lsd, the more aggressive they are, they more you will understeer, i experimented that with my GT3. try to turn a cup car on street, at low speed when wet, you will see what i mean.

why the lack of lsd is a negative cited by press. well, if i were to choose, i would like to have one, whether plate type of torsen. i also complain that at such price 60k+ we aren't getting one. but the fact is we DONT get one. with that in mind, to get one you have to pay quite a bit of money for the part and lots for labor. i dont know much about torsen type, but plate type you have to open the gearbox. how many ppl do you trust to open up your gear box to do the install?

finally, some ppl say that miata, s2k etc, are cheaper cars but all come with LSD. well. there are LSD's and there are LSD's. most of us who track GT3 aggressively destroy the factory LSD in a year, 10-20k miles. it's pretty expensive to fix/replace it. many 993's have LSD but most of them aren't working.

if you think you NEED and actually USE the LSD, you have to be prepared to service it. this is not plug it in and last forever thing.

not trying to scare anyone off. i would LOVE to have plate type LSD for my car in my application (i only use it on track, rarely on street) but i am just not ready to pay for a good one (guard transmission makes some incredible LSD's, better than oem and some argue better than porsche motor sport as well) and find someone trust worthy to open up the gear box.
 
#455 ·
plate type lsd, the more aggressive they are, the more you will understeer,
Yes.

I used to autocross a Lotus Europa that someone had cursed with a plate-type LSD. With good surface and fresh sticky tires, you would hardly notice it. With lesser tires or an autocross surface that was wet or just plain substandard, the car pushed like crazy. Once it started to push, there was nothing solving it: power-on, power-off, put in the clutch and coast, nothing.

Picked up a bottle of Slick-50 ManTran. Label said "do not use with limited-slip differentials". I poured in the whole bottle. Lowered the breakaway torque from 90 foot-pounds to 20. I put in a new bottle every spring. This helped a lot, and was less-trouble than splitting the gearbox to amputate the LSD.

After that, I had a Miata with the factory TorSen. Worked very well in autocross.

Then I bought a Caterham Seven. Installed 4.11/1 gears and a Quaif torsen-type LSD.

Sold the Caterham to buy a 2005 Lotus Elise. Open diff. (Lotus said the car was no faster around their test track with a TorSen than with an open diff. True, but in the USA we autocrossers wanted the TorSen. They finally became more-common in 2006 models.) I put in a huge front bar, no rear bar, lowered, 500 pound/inch springs on the front, 800 on the back, trick balljoints to flatten roll axis. I didn't usually get a lot of wheelspin, but the SCCA National-Champion drivers who who drove my car could. I'm not going to win any national championships, I'm just addicted to autocross since 1968.

After over a decade with the Elise, I replaced it with a 2011 Cayman 2.9 PDK Sport+. This has an open diff with wheelspin controlled by the rear brakes. Seems to work well-enough in autocross and I can afford to keep it in rear brake pads.

I have just picked up a quicker Caterham: 1700 Super Sprint. DeDion rear end with disc brakes. Wheels up in neutral, they both spin the same way. One wheel down, I can’t turn the lifted wheel. I was able to steer it while pushing it into my shop, so it is not a spool, but apparently a plate-type LSD. I have not had it on an autocross course yet. There is more weight on the front wheels than there is on a mid-engine car. If that, and the adjustable rear sway bar, is not enough to kill the evil effects of the LSD, maybe I can still buy ManTran. This is now my only manual-trans car and will be an interesting challenge to master: It is right-hand-drive, first one for me.

Two autocross cars. If the weather is perfect, the Seven. If it is raining cats and dogs, the Cayman is weatherproof and has Please Save Me.
 
#15 ·
No. I do not have 20 grand doing nothing in my back pocket.:D

Fitting an LSD is something I will probably get round to, when my Cayman S arrives next spring. The Quaife unit seemed like the best option. The price is reasonable and it must be fairly bullet proof, if they are offering a "Lifetime Guarantee".

I would rather trust the work to a gearbox specialist than an OPC.:rolleyes:
 
#18 ·
isn't the understeer something you'd feel on the track as well? I'm not sure what the difference is between feeling a lot of understeer during regular driving, vs track on a tight corner. Or do you just outweigh the understeer with the advantages?
i dont know how technically to explain this. but on track you are exiting the turn much much faster, the car drift a bit. that helps you turn.

on street, you don tgo this fast. you will feel the understeer more.

sorry, i know this is very crude of an explanation. but if you drive an aggressive plate type LSD you will konw what i mean. a drive is worth 1000 words.

drive a street GT3 throgh a slow tight turn in the wet. you will feel it big time.
 
#19 ·
Quaife ATB Diff
Below is some blurb but it helps to understand how it works.....


The Automatic Torque Biasing differential is Quaife's unique patented design, and is an after-market differential that provides smooth, constant traction for racing or slippery road conditions.
The characteristics of the differential are that it progressively locks as torque increases; there are no plates or clutches to wear out, as the more conventional limited-slip designs incorporate
With an normal open differential, fitted as standard on most cars, much precious power is wasted through wheel spin under acceleration. This happens because the open differential shifts power to the wheel with less grip - along the path of least resistance.
This differential, however, does just the opposite. It senses which wheel has the better grip, and automatically biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel.
This differential also controls loss of traction when the drive wheels are on slippery surfaces such as ice and snow or mud, providing the appropriate biased traction needed to overcome these adverse conditions. This ATB differential provides constant and infinitely variable drive. Power is transferred automatically without the use of normal friction pads or plates seen in other limited-slip designs.
This differential is extremely strong and durable, and since it is gear-operated, it has no plates or clutches that can wear out and need costly and regular replacement.
This differential is great for street driving or racing. Racers don't have to put up with locking mechanisms or spools that tear the steering wheel out of their hands when cornering. Because it behaves like an open differential during ordinary driving, street drivers will have trouble telling it's there until pushing the cars towards its limits.
This differential is proven in everything from SCCA Rallying to drag racing and Formula 1. It provides autocrossers with such an advantage, it has become "required" equipment for a winning effort.

Another small point:-.........
Quaife's ATB differential comes complete with a Lifetime Warranty.
To date, we have not had any warranty claims!


As I'm in the process of becoming a sponsor to the site I can tell you the following:-
It's also going to be a good price, Now Confirmed at £660 ($1292.85 at todays exchange rates)
Watch this space as I'm having a quantity made as we speak and will let you know time factor and/or delivery dates (Depending on interest a group buy might also be available)
A Different variation is available now off the shelf for 3.2 S Boxster S gearbox if anybodies interested at £750 ($1465)

Anybody remotely interested????
 
#20 ·
I do plan to put an LSD on my car at some point. The Quaife seems like the best compromise for a daily driver/weekend DE type CaymanS. If the group buy is right, I'd jump in. How many hours of labor do expect the install to take at a decent Porsche service shop?
 
#21 ·
Taking the diff out and fitting existing crown wheel to new diff is not at all difficult and would only take ½ hour or so. Setting the pinion backlash is an unknown to me at the moment. On most car’s it’s a crushable type washer, but as yet I don’t know on this gearbox. Either myself or possibly K-Man S would do a “article” to accompany the diff for fitting instructions. That's the intention anyway.
 
#23 ·
I'd be interested in installing an LSD at some point too. The torsen type LSD seems like the more practical type for me as I'll be driving the car more on the street with a few track days and autocrosses in between. Plus coming from the Honda world where there were some guys who were fitting the clutch type and having to have them "rebuilt" after a few years.
 
#25 ·
dont just put an LSD on your car.
figure out why you need it.
if you drive on street, even if you drive recklessly, you DONT need LSD. it either make you understeer too much or its presence is not felt, money wasted.

if you AX, you most likely need torsen.

if you track, DE, or race, you need plate type. torsen wont work if you lift wheel off ground and that's what happens if you are in the tight turn on track.

if you are spinning inside rear tire (when the tire is on the ground) you need stickier rubber. cayman s at 295hp shouldn't be spinning rear inside tire if it's on dry pavement with good rubber (notice, i said ON the pavement) if you are lifting tires, you need plate type.

grossly simplified, yes, but this is the gist of it.
-at DE you are lifting a wheel off the ground, but not at an autocross which is all tight turns & rapid transitions?? scratching my head at this. if you are lifting an inside rear wheel (and your car is not FWD) you've got serious setup issues or 8 foot wide slicks...i guess a torsen is a limitation if you are doing a lot of curb hopping, but not really an issue at most tracks, or for most drivers. torsens work great and are maintenance free. if you track/AX a lot you will need to get plate type diff rebuilt periodically and for alot of people that is cost/inconvenience prohibitive.
 
#26 ·
Taking the diff out and fitting existing crown wheel to new diff is not at all difficult and would only take ½ hour or so. Setting the pinion backlash is an unknown to me at the moment. On most car’s it’s a crushable type washer, but as yet I don’t know on this gearbox. Either myself or possibly K-Man S would do a “article” to accompany the diff for fitting instructions. That's the intention anyway.
you do not need to reset the pinion depth & backlash if you are just swapping the ring onto a new diff. unless porsche is differant but i swapped a quaiffe myself on another car and if the diff is made correctly you are not changing the location of the ring gear relative to the pinion. its truely a bolt in...
 
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