Traction control Vs CDL & Transverse DLs

[Nigelw]

As above really, had a rubbish day today as my weekend staff did not show up and I had to do the boring and mundane chores myself, and was pondering this as I know that LR refitted CDL to the D2 as TC alone was not enough, but I also know that a lot of Freebies have been getting around very easily in the slippery snow and ice with their TC system.

But is there any comparison between a TC equipped vehicle and a truck with 3 diff locks?

So what does every one else think?

[FridgeFreezer]

TC is awesome and can do things that mechanical stuff just can't, but equally it can't match "everything locked" in outright ability to put 100% of the power to the wheels. The newer stuff (Disco 3 / new RR onwards) has both.

[NRS91]

TC is awesome and can do things that mechanical stuff just can't, but equally it can't match "everything locked" in outright ability to put 100% of the power to the wheels. The newer stuff (Disco 3 / new RR onwards) has both.

agreed tbh!

[Escape]

The freelanders actually do have (some sort of) CDL: the viscous coupling. So that will help the traction control a lot.

I had TC on my Defender and later upgraded to ARBs. As said the TC is amazing and it got me through some bad stuff. It was a great way to learn to drive offroad, because the TC would often correct my mistakes and let me know, without getting stuck. And without having to think about engaging lockers myself. But TC does have its limitations. The biggest problem is that TC is always reactive, it can only try and brake a wheel after it is slipping. So you're converting engine power to heat, and with prolonged use, the TC will shut down to prevent overheating of the brakes.

Even on the newer LRs with terrain response, there is still a small disadvantage compared to manual difflocks. Especially when starting off, the system will allow some slip and this can be the difference between getting stuck or just being able to get going with manual difflocks. I've seen this in both an RRS and a Disco3, compared to a Defender with ARBs or a P38a with Ashcrofts.

Big advantage of TC/Terrain Response is the speed with which it can react to differing conditions, as opposed to the binary and relatively slow operation of manual lockers.

Filip

[FridgeFreezer]

The way (LR) TC works is by braking the spinning wheel (the later stuff also controls engine/gearbox/suspension) so by definition it will be limited in some ways compared to mechanically locking everything - in some situations you have to keep your foot down to generate enough "spare" power so it can then "waste" it by applying the brakes.

TC can't see what's coming either.

What TC CAN do is give you the control of having the diffs open whilst preventing wheelspin. It can also save you from bad situations and keep you pointed in the right direction.

As I said, the combination in the newer stuff where they have mechanical lockers AND terrain response is about the ultimate.

[Escape]

As I said, the combination in the newer stuff where they have mechanical lockers AND terrain response is about the ultimate.

I'd agree, if only you'd have the possibility to use the lockers on command, instead of relying on the computer to decide wether it's needed or not.

[dirtydiesel]

The ultimate combo is detroit trutracs front and rear and traction control.

They perfectly compliment each other.

I wonder what a freelander would be like with a quaiffe atb in the back?

[BogMonster]

I wonder what a freelander would be like with a quaiffe atb in the back?

Hung up in a different place?

[RangeyRover]

I can only compare cdl to disco ii with tc.

In my experience tc is very capable. It takes some getting used to, especially the noise, and I do wonder if the constant braking, especially in sand will overheat the brakes.

As I have cdl in my disco, which cuts off the tc I can make a direct comparison in the same car. And I want the tc on. Contrary to.popular opinion in aus, the disco is improved in my experience by the tc being active in the sand. It really makes a difference to the car. To the point of making me think of Ashcroft LSD rather than full lockers for the disco.

Anyone have any thoughts on that combo? Or should I get full lockers and let the tc work on them open and lock up if really in trouble?

Edit: I see Dan has said practically the same thing above, care to add any more Dan?

[dirtydiesel]

Edit: I see Dan has said practically the same thing above, care to add any more Dan?

A guy I knew had a 110 td5 with TC worked very well up to its limits, he then wanted lockers I pushed him toward arb but he took some advice (I believe from Ashcroft) to go for a pair of Detroit true tracs.

These came shimmed differently front and rear, i fitted them for him, and we went out for a play, I was feeling quite smug and told him a few times how they were all going to fight each other and tie them selves in a knot.

I had to eat my words, I had a stock swb gwagon on bfg muds he was on bfg at's and he followed me everywhere. (Dry day at kirton quarry)

They seemed to work at there best with the anti-stall function on the td5.

Normally when you watch a TC equipped car drive to the limits of it's traction, there is a momentary pause while the TC redirects power, this momentary pause normally breaks the momentum and causes a failed hill climb or such, the soft lockers seemed to bridge this pause and give him seamless traction.

[Aragorn]

Torsen style LSD's like the Truetracs effectively amplify the braking effect of the traction control, and make it work a lot better. Instead of the brakes fighting the engine alone, the brakes help the diff to do its job.

[Bowie69]

Have to say, for a point and shoot, no switches/compressor or extra plumbing to get ripped off, torque biasing diffs like the ATB and Truetrac really are a good thing to have.

It's a shame that the RRC only came with TC on the rear, but I suppose if you want it anywhere it should be there

[Escape]

As I have cdl in my disco, which cuts off the tc I can make a direct comparison in the same car. And I want the tc on.

I didn't know the TC was turned off when you engage the CDL. Seems a bit counter-productive, as you'd want all the traction you can get when engaging CDL.

On the Defender TD5 it certainly keeps on working with CDL engaged...

[Theo disco]

I didn't know the TC was turned off when you engage the CDL. Seems a bit counter-productive, as you'd want all the traction you can get when engaging CDL.

On the Defender TD5 it certainly keeps on working with CDL engaged...

I didn't know as welll. I had a disco II and had a manual controle fitted to the CDL meself. This way I had the TC AND CDL when I wanted. CDL did not turn my TC of. I only installed a Boden cable to the small lever on top of the central diff lock shaft.

[RangeyRover]

The cdl does not disengage tc when you engage it still running. If you stop and restart with cdl in, then tc doesn't work, at least on mine!

Bearing in mind it was not supposed to have cdl, mine is fitted with a homemade lever.

[Escape]

The cdl does not disengage tc when you engage it still running. If you stop and restart with cdl in, then tc doesn't work, at least on mine!

Bearing in mind it was not supposed to have cdl, mine is fitted with a homemade lever.

Strange. Is there a difflock light on the dash? If so, that signal would have to be used by the TC as well. So you could intercept it, giving you CDL and TC.

Edit: just looked in the electrical library, there is indeed a wire going from the CDL switch to pin 9 of the SLABS. But no reference to what is does.

[Tanuki]

The thing I really dislike about all forms of mechanically 'hard' locked diffs is the horrid and unpredictable effect they have on the steering, specially in sharp corners where at least one wheel is obliged to lose traction and slip to get round the curve.

[Theo disco]

I am in the race for the Truetrac type to replace the front and rear diff. This will not lock 100% but together with the central difflock it will do most. On more than one occasion it will work fine and good. There are only a fue extrem situations were this setup has it limits.

Overall I think it is relailable, simple and effective

On grass and wet land you dont have the "slip/slide" of the locked wheels from a 100% difflocker but all wheels will do there work well. Also when driving a curve, the truetrac type of locker works. as a locker cant do this without sliding/slipping wheels.

Even on tarmac you have 4x4 where you beter not use 100% lockers.

Ashcroft makes a Truetrac type one as well now. Only not for the Sallsbury.

[Escape]

The thing I really dislike about all forms of mechanically 'hard' locked diffs is the horrid and unpredictable effect they have on the steering, specially in sharp corners where at least one wheel is obliged to lose traction and slip to get round the curve.

Agreed, which is why I don't like Detroit and other no-spins (apart from the fact that on road you can only hope they will unlock when needed).

With selectable lockers, it's up to the driver to judge if there is enough traction in the corner to disengage or that wheelspin will occur anyway and you'll have to power through with the lockers. I must admit a torsen type in the front would be a benefit in such situations. But I still prefer to play with the buttons.

[RangeyRover]

Strange. Is there a difflock light on the dash? If so, that signal would have to be used by the TC as well. So you could intercept it, giving you CDL and TC.

Edit: just looked in the electrical library, there is indeed a wire going from the CDL switch to pin 9 of the SLABS. But no reference to what is does.

I'm sure that's the pin you put a switch into to disable the tc. This page talks a lot about it http://www.discovery2.co.uk/diff_lock.html