Are LSDs being phased out?

[Ron0z]

The RedBook is my bible. It's an excellent guide to buying and selling. It provides an indication of a car's worth as well as various technical specs, including the standard equipment. (Assuming it's accurate, of course), and options that might be fitted when new. I find this sort of thing useful.

Anyway, to the point: I'd been becoming accustomed to seeing things like Limited Slip Diff as a standard feature. So, when I stopped seeing that in the write-ups I wondered if they'd made a mistake. Particularly on newer vehicles. But of course, what I am seeing are things like 'Traction Control' often described as follows: Control - Electronic Stability; Control - Rollover Stability; Control - Traction.

Is it the case that manufacturers are using ordinary old fashioned Open Diffs but adding alternative technology that does the same thing as LSD or locking diff?

 

[Hoyks]

LSD's have never been that good for off roading anyway, the locking diff has always been superior.

The other thing is that if you have to fit an ABS module and a computer to run traction control and stability control and you already have a braking system installed, why not use that to produce the same outcome as a LSD?
It saves you both money and complexity in the vehicle design.

If you want extra capability (or the customers demand it, even if they will never use it), then drop in a e-locker which would be the preferred choice as it is either on or off and the ECU then knows what drive line configuration it is playing with.


And I have been mis-quoted below, I never mentioned Patrols.

 

[ipch]

LSD's have never been that good for off roading anyway, the locking diff has always been superior.

LSD's in Patrols work extremely well and are known to be the best for non modified vehicles. With a Patrol a locker goes in the front if you are that way inclined and the LSD looks after the back.

Traction control or stability control has replaced the LSD. and in some cases work just as good as a locker.
Electronic features such as down hill assist and turning assist would just be inpossable with a LSD.

Its a sign of the times and we simply adapt to new technology or stick to the old stuff.
Close to home and in the high country i take the old tech. But when touring its always the new one.

Ian..........

 

[mikehzz]

Traction control is a component of stability control, they aren't the same. Brake traction control simply brakes a wheel that is in the air spinning while the opposite wheel is doing nothing. This forces drive to the non spinning wheel. Stability control is a whole different kettle of fish that aims to restore stability to an unstable car by using brakes and engine power management to slow the car and straighten it up. Land Rover have got it right, you can turn off the stability control when off road because otherwise the car goes nuts aznd reduces power when you don't want it to, but you can't turn off traction control because a wheel spinning in the air is not affecting anything. Every car maker calls the systems something different and they all opperate slightly differently which adds up to total confusion. Good brake traction control is awesome off road and much better than an LSD.

 

[Hoyks]

Traction control is a component of stability control, they aren't the same.

I never said they were, but they all rely on the ABS module to apply braking force to the wheels.

 

[mikehzz]

The ABS doesn't apply the brakes, it stops the brakes from locking, (anti-lock braking system). More correctly, all the systems rely on the same wheel sensors to do their respective jobs.

 

[shanegtr]

The ABS doesn't apply the brakes, it stops the brakes from locking, (anti-lock braking system). More correctly, all the systems rely on the same wheel sensors to do their respective jobs.

Well technically ABS does apply brake pressure. The unit will release and reapply the hydraulic pressure to a wheel (or an axle group in older systems) when lockup is detected.

 

[mikehzz]

ABS happens when you are stamping on the brakes as hard as you can. It seems funny it would apply pressure itself. I thought it pulsed to relieve pressure if the wheel sensor indicated the wheel was going to lock and skid. If it relieves the pressure and the wheel rotates then it just lets your foot pressure apply again. Once again, every manufacturer has a different system and stability control, traction control and autonomous braking all apply the brakes.

 

[Hoyks]

Your vehicle doesn't have multiple braking systems, just the one system that does multiple jobs.
The ABS module has servo motors to relieve the pressure for fractions of a second under heavy braking, but also needs a pump or else with all the venting of pressure your foot would sink to the floor or you'd be madly pumping to maintain pressure in the system and apply full hyd pressure the fraction of a second after the brakes were released.

One of those things that is a bit of an effort to initially design, but once it was in they found all sorts of extra stuff it could do really well with minimal extra hardware and some code in the software.

 

[cam04]

ABS happens when you are stamping on the brakes as hard as you can. It seems funny it would apply pressure itself. I thought it pulsed to relieve pressure if the wheel sensor indicated the wheel was going to lock and skid. If it relieves the pressure and the wheel rotates then it just lets your foot pressure apply again. Once again, every manufacturer has a different system and stability control, traction control and autonomous braking all apply the brakes.

It does brake on its own. That’s how hill descent control works. It is also how traction control, trailer sway control, and stability control works (and aeb, radar cruise, and in the case of hilux’s - lane keeping).
in my car, in low range if you put the rear diff lock on, the abs light comes on because the front end traction control becomes disabled.

 

[peterfermtech]

The new dual battery thread(s)

 

[discomatt]

Look out people the anti off topic member will be jumping all over you soon, this tread is only to be about LSD diffs not how ABS works.
Then again maybe that only applies to some members when the thread goes sideways
Back to it, my old 4by, also not allowed to mention brand or any other details, but I have put Harrop LSD diff centers in it and it works very well , gentle on the drive train, safer on road, excelent traction off road except in the most extreme situations where a full locker would be better but in those situations I left foot brake and it locks them up almost as much as a traditional locker would

 

[RBJET]

I took some LSD the other day and got pretty phased out

 

[Ron0z]

If you want extra capability ... then drop in a e-locker which would be the preferred choice as it is either on or off and the ECU then knows what drive line configuration it is playing with.

Does the vehicle have to be stationary to engage or disengage an e-locker?

 

[shanegtr]

Does the vehicle have to be stationary to engage or disengage an e-locker?

No, they need a little bit of cross axle rotation for the locking mechanism to engage (at least that's the case with harrop/eaton elockers)

 

[Chatty]

When I was a young lad LSDs were talked about all the time and were seen as the duck's guts. I haven't heard a discussion about LSDs in yonks - and I think that's due to the traction control systems available now. Maj the Paj was awesome in the rough stuff without an LSD, or diff lockers - that ability to lock up a spinning wheel (using the ABS sensors to sense wheel rotation and the ABS pump to apply the brake to the spinning wheel) worked well for us many times.

As for the discussion about whether ABS is an "active" system (that is, with it's own pump)...
ABS certainly didn't start that way many years ago - it "simply" momentarily released brake pressure to a wheel that was about to lock up. Most motorbike ABS still works this way. But the ability to utilise the system for other things has seen active pumps incorporated to achieve many outcomes Some that come readily to mind are:
Stability control by applying the brakes to individual wheels without any brake pedal pressure
Hill start assist holding the brakes on for hill starts
Hill descent control
Lane keeping assist - Toyautos are notorious for trying to rip the steering wheel out of your hands by applying individual front wheel braking to steer you back into what the vehicle thinks is the lane you should be in
Emergency autonomous braking - sadly about to become mandatory on all new vehicles in Australia

 

[Ron0z]

Emergency autonomous braking - sadly about to become mandatory on all new vehicles in Australia

Maybe not too sad. Why sad?

I clobbered a wallaby hopping across the road in my Honda Odyssey just as I was coming over a crest. I broke hard enough that all I got was a broken headlight and I think it got a broken hip. Maybe more. Had I been quicker, and I thought I was quick, it might have kept going uninjured and I wouldn't have had a car repair. There's probably some good to such braking systems.

 

[shanegtr]

Maybe not too sad. Why sad?

Well I think its sad as people will just think its another system that they can rely on to stop the car and so will pay less attention to what they are doing.

 

[Chatty]

Maybe not too sad. Why sad?

I clobbered a wallaby hopping across the road in my Honda Odyssey just as I was coming over a crest. I broke hard enough that all I got was a broken headlight and I think it got a broken hip. Maybe more. Had I been quicker, and I thought I was quick, it might have kept going uninjured and I wouldn't have had a car repair. There's probably some good to such braking systems.

As @shanegtr said, another system that people will over rely on.
It will be like ABS - when ABS was introduced the rate of collisions actually increased as drivers believed that ABS made them bullet proof, so they could drive faster, follow other vehicles closer and brake later. I think that with EAB people will no longer believe that they need to scan down the road for hazards as the "system" will save them from their inattention and stupidity.

All the AEB systems I've seen so far wouldn't cope at all well with your wallaby/roo strike - they move way too fast and blend into the background too well for these systems to easily distinguish.

Tesla's Autopilot (generally acknowledged as state of the art) has been proven to not brake in a number of critical areas - including when around emergency vehicles. This does not give me great hope in the ability of these systems.

 

[peterfermtech]

None of that gadgetry seems to help those driving those large German SUVs around Doncaster unless that lane change stuff stops working when you are straddling 2 lanes.