then what is the different on those 1.5way and 2 way lsd by kaaz!?
http://www.kaazuk.com/products.php
http://www.kaazuk.com/products.php
aftermarket lsd for 944!??
- Thread starter bazza
- Start date
Neil Haughey
New member
These guys by any chance?
http://www.modenaengineering.com.au/index.htm
http://www.modenaengineering.com.au/index.htm
Neil Haughey
New member
Great up to the point where your pulling 1g and the outside rear wheel starts to slip. At this point the inside wheel could well have next to zero grip (if the 1g is perpendicular to the cars centre line). Under such circumstances the ATB is likely to act like a standard open differential or worse switch torque between the wheels, same I guess if the inside wheel is lifted.
On a track like Bedford having the ability to trail brake hard into the turn 2 chicane, which a LSD with a high ratio on deceleration gives is a massive advantage. As I posted some time ago the M3 CSL I was having fun with put as much time into me on that one corner as the rest of the track put together. In other words a differential that locks on deceleration would make my car much faster on that track whereas the ATB wouldn't give this advantage.
On a track like Bedford having the ability to trail brake hard into the turn 2 chicane, which a LSD with a high ratio on deceleration gives is a massive advantage. As I posted some time ago the M3 CSL I was having fun with put as much time into me on that one corner as the rest of the track put together. In other words a differential that locks on deceleration would make my car much faster on that track whereas the ATB wouldn't give this advantage.
sawood12
New member
It would only lock when the speed differential between the two wheels was enough. I'm not sure what that radius of curve would be and how often a 40% LSD would actually lock. At Bedford the only bend I was spinning my inside wheel on was the hairpin - but like you say it was at that bend the M3CSL was making up most ground.
I understand and respect other peoples experiences and will bow down to them, however how much of this is down to the fact the current manufacturers of ATB's just don't make products that are as good as the companies that make conventional LSD's? Afterall there is decades more experience with conventional LSD's and thousands more companies making them and who knows what patents and copyrights are preveinting aftermarket companies copying the best ATB technology from the original inventors. I keep on coming back to the simple principal that through a bend you want the majority of the torque going to the outside wheel and this situation would give you the best grip, stability and drive out of the bend. Afterall this is exactly what Ferrari are doing with their hugely complex active e-diff, so maybe it is too much to expect from a dumb mechanical diff and conventional LSD are still the way to go. And the 996GT3RS with its dumb mechainical LSD got the same time than the F430 Stradale when the Stig put them through their paces, so it seems the fancy e-diff makes the Ferrari just about as good as the GT3RS!! Anyway i'm now convinced and sold on the idea of a conventional LSD. The Quaiffe ATB has been struck from my mods list!!
I understand and respect other peoples experiences and will bow down to them, however how much of this is down to the fact the current manufacturers of ATB's just don't make products that are as good as the companies that make conventional LSD's? Afterall there is decades more experience with conventional LSD's and thousands more companies making them and who knows what patents and copyrights are preveinting aftermarket companies copying the best ATB technology from the original inventors. I keep on coming back to the simple principal that through a bend you want the majority of the torque going to the outside wheel and this situation would give you the best grip, stability and drive out of the bend. Afterall this is exactly what Ferrari are doing with their hugely complex active e-diff, so maybe it is too much to expect from a dumb mechanical diff and conventional LSD are still the way to go. And the 996GT3RS with its dumb mechainical LSD got the same time than the F430 Stradale when the Stig put them through their paces, so it seems the fancy e-diff makes the Ferrari just about as good as the GT3RS!! Anyway i'm now convinced and sold on the idea of a conventional LSD. The Quaiffe ATB has been struck from my mods list!!
Neil Haughey
New member
Yes but on that turn the CSL was not taking much if anytime out of me on either of the first 2 corner exists due to traction. Most of the gap was down to him being able to turn in then brake hard, whereas in me S2 I had to start braking before turn in and gently trail brake into that corner. I tried braking harder and latter a few times but this would just cause the car to gently oversteer, and TBH felt very unstable.
The other places where he was quicker was the left hander after the hairpin (too much understeer from me), the mega high speed left hander (again a little understeer here but more balls would probably do the job for me), and the complex in the far corner where I was in the wrong gear had slightly wrong approach. I have put more camber on the front and the 968 M030 ARB to get a more even roll characteristic (I had mostly squat at the back but loads of roll at front which meant sometimes I was lifting one of the front wheels). This with the dampers turned up at both ends should keep the car down more on the turns (I had the dampers set as low as you can without a bouncy ride but had to turn the fronts up to 50% hard to quell oversteer on most of the corners on the track).So far on road driving the car feels much more tied down into the corners.
With respect to ATB/torsen diffs it is worth mentioning that Porsche did use them in the 968 but AFAIK have not used them since in any of the 911 variants for either racing or as an option on road cars. They make a lot of sense by my understanding on FWD cars and rally cars where one definitely does not want more understeer and something which helps turn the car will make it faster.
The other places where he was quicker was the left hander after the hairpin (too much understeer from me), the mega high speed left hander (again a little understeer here but more balls would probably do the job for me), and the complex in the far corner where I was in the wrong gear had slightly wrong approach. I have put more camber on the front and the 968 M030 ARB to get a more even roll characteristic (I had mostly squat at the back but loads of roll at front which meant sometimes I was lifting one of the front wheels). This with the dampers turned up at both ends should keep the car down more on the turns (I had the dampers set as low as you can without a bouncy ride but had to turn the fronts up to 50% hard to quell oversteer on most of the corners on the track).So far on road driving the car feels much more tied down into the corners.
With respect to ATB/torsen diffs it is worth mentioning that Porsche did use them in the 968 but AFAIK have not used them since in any of the 911 variants for either racing or as an option on road cars. They make a lot of sense by my understanding on FWD cars and rally cars where one definitely does not want more understeer and something which helps turn the car will make it faster.
sawood12
New member
They have used them on their 4wd cars but probably only on the centre diff but in conjunction with some fancy computer controlled viscous couplings. In this configuration if your rear axel looses traction i.e. oversteer the torque is transferred to the front axel. However I believe they've used another more sophisticated system with the 997 C4's.
George Elliott
New member
The original quattro's had a locking centre diff (and rear diff) and in 1988 got a torsen centre diff. The only way to make the nose heavy thing turn in was to cut a foot out of it's wheelbase, provide 500bhp and put Walter Rohrl in it. With a fuel injector in the turbo hotside to keep the lag down, and his left foot on the brake most of the time, he could do wonders in it.
My experience of the early pneumatic operated system and the later torsen system was it made little difference to steering the brutes. Traction was mind blowing with both setups. It drank fuel and ate front tyres, but it would do 90mph in a river of water with a force 8 crosswind, - and it would feel like the driving conditions were perfect.
The LSD is the old fashioned way of engineering a locking action into a diff, the locking action works very well on my 944T and can be felt regularly on slippy surfaces under load. On a previous 944T without LSD it was a frustration as it was effectively 1 wheel drive, as is any 2 wheel drive open diff car. On a 914-6 (2.4E) and 964(RS) with standard LSD I have been pleased with the ability to drive both rear wheels when you want to. I would not swop for a torque sensing diff as it has a reaction time - traction is always variable so it is continually adjusting and thats not ideal. To address this :-
Mitsubishi produced a very elaborate system with active yaw control. It takes various inputs, - Steering wheel position, Throttle position , mph, lateral & for/aft G sensing, and will adjust the delivery of torque to the wheel it considers it should go to. (according to conditions - Ice / Gravel / Tarmac preselected by the driver.) Mitsubishi have overcome the shortcomings of a torque sensing diff by controlling hydraulic pressure on the plates in the diff. They did all this and made it work with technology as the Japaneese do, but its a different type of car to a 944. It drives you - not you drive it. Plus the Oil in the diff needs changing every 4500miles. Technically its the best traction device available IMO
Standard LSD - If its not broke don't fix it?
George
My experience of the early pneumatic operated system and the later torsen system was it made little difference to steering the brutes. Traction was mind blowing with both setups. It drank fuel and ate front tyres, but it would do 90mph in a river of water with a force 8 crosswind, - and it would feel like the driving conditions were perfect.
The LSD is the old fashioned way of engineering a locking action into a diff, the locking action works very well on my 944T and can be felt regularly on slippy surfaces under load. On a previous 944T without LSD it was a frustration as it was effectively 1 wheel drive, as is any 2 wheel drive open diff car. On a 914-6 (2.4E) and 964(RS) with standard LSD I have been pleased with the ability to drive both rear wheels when you want to. I would not swop for a torque sensing diff as it has a reaction time - traction is always variable so it is continually adjusting and thats not ideal. To address this :-
Mitsubishi produced a very elaborate system with active yaw control. It takes various inputs, - Steering wheel position, Throttle position , mph, lateral & for/aft G sensing, and will adjust the delivery of torque to the wheel it considers it should go to. (according to conditions - Ice / Gravel / Tarmac preselected by the driver.) Mitsubishi have overcome the shortcomings of a torque sensing diff by controlling hydraulic pressure on the plates in the diff. They did all this and made it work with technology as the Japaneese do, but its a different type of car to a 944. It drives you - not you drive it. Plus the Oil in the diff needs changing every 4500miles. Technically its the best traction device available IMO
Standard LSD - If its not broke don't fix it?
George
sawood12
New member
Neil, just a thought that struck me today while I was mulling this thread over in my head (yes, a quiet day in the office), if you were trailbraking deep into the hairpin with your ABS chattering away then surely the reason why the M3CSL was going deeper was because he had better brakes and outbraked you. Those things do have ceramic braked IIRC. Isn't the whole point of ABS that you can steer while you brake hard and the ABS acts a bit like traction control in reverse and prevents you from spinning out of control. With the ABS on it should be able to handle the weight shift and shift in torque across the axels so the type of diff you have is irrelevant until you get back on the power or release the brakes and you are into overrun?
Neil Haughey
New member
No where near braking hard enough to get ABS going on that corner. When I said gently trail braking what I mean is braking as gently as you would under normalish road conditions. The guy in the CSL just chucked it in well after the cone and stood on the middle peddle. When I asked around everyone with a 944 seem to have the same problem, I asked Andrew and he was starting to brake at pretty much the same point just before the cone. Apparently the M3 CSL (probably all M3) has some clever electronics called Corner Brake Control.
If anything I was outbraking the CSL on the high speed stop into turn 1. Still was shocking though how I could match him round half the track and then loose maybe 150 ft at least on the other half.
The ABS system on the 944 is not a stability control system so don't expect it to stop you from getting out of shape in corners, the sort of rear end looseness we are talking about here is pretty easy to catch but of course having to bail out on any corner is going to mess up a lap.
If anything I was outbraking the CSL on the high speed stop into turn 1. Still was shocking though how I could match him round half the track and then loose maybe 150 ft at least on the other half.
The ABS system on the 944 is not a stability control system so don't expect it to stop you from getting out of shape in corners, the sort of rear end looseness we are talking about here is pretty easy to catch but of course having to bail out on any corner is going to mess up a lap.
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