Here is some responses to questions on Outerlimits4x4 that were put to the developer of this system a couple of years back. It should give you a pretty good idea about the system.
I guess the biggest question is how well does our electronic traction control work? Is it as good as lockers in terms of making a vehicle able to drive over stuff?
Let me state first off that in terms of getting the most amount of traction possible you can never do any better than a 100% locking differential.
So looking at hardcore type wheeling (like competition type stuff etc) - I would guess that in well over 90% of situations that requires twin lockers to get through you will get exactly the same result with our traction control. Now in the last 10% of situations you will definately notice that the traction control behaves differently to the lockers. The most common situation for me would be a steep rocky climb with offset ledges - something that you need to drive with throttle and momentum (whether lockers or ETC) - with the ETC you will start to notice the time delay and extra wheelspin that the traction control needs to operate. If the climb is difficult enough then you may find that a rig with lockers will be able to drive it and one with ETC wont. That being said I have never found an obstacle that I could drive with double lockers (ARB) that I couldnt drive totally open diffed with the traction control (this was back in the day when I ran ARB'd dana 44s as well as the traction control on the blue rover with 36in tyres and then 42in tyres)
These last 10% of situations are also the places that you really risk breaking something (like CVs or crownwheels for instance). The traction control is just so much easier on axle components. I would guess that an ARBed axle with 35in tyres would be about the same strength as a traction controlled axle with 42s - and Im totally serious on this point. The traction control is just that much easier on axles it isnt funny. Out of the hard core rigs that I wheel with that run hilux front CVs which is basically myself on 38s, Adrian on 38s and Rob on 42s that run front traction control compared with Tony on 38s and Beebee on 38s with front lockers the difference is amazing. Myself, Adrian and Rob drive the arse out of our rigs with absolutely no concern with front axle breakage and we rearly break CVs. Tony, who really drives carefully with his front locker breaks more CVs than the 3 of us combined and Beebee, who drives the arse out of his rig with his front locker breaks more than Tony again.
So it really depends on how strong your axles are. If you got axles that you carnt break then the lockers are the perfect choice - you could never do better than that but if you are worried about breaking stuff (particularly the front axle) and you find yourself turning off the front locker on the difficult throttling climbs or only use the front locker as an absolutely last resort then the traction control will probably make the rig more capable.
At the moment in my tube buggy which runs hilux limited slips and traction control (no lockers at all which is why its called the Lockless) there is nothing that this rig hasnt been able to drive that has been driven by Tony (twin lockers), Adrian (rear locker and front traction control) the Mogrover (twin lockers), Beebee (twin lockers), or Rob (rear locker and front traction control). In fact there is one new climb that so far only the Lockless had managed to drive and nobody else has. Tony has been out there a couple of times and he has broken both times and has yet to drive it. It took me a few tries to get it (cause its a bit offcamber) and I actually rolled completely over back onto my wheels before i drove it on my next attempt.
In the non hard core type wheeling, the sort of wheeling that you are going to do with your wife and kids in the car, I couldnt imagine there will be a situation where the traction control wont work as well as the lockers. It will probably work better because its totally automatic - you just turn it on and forget about it whether you are driving uphill, downhill, corning or on the flat. The traction control wont do a thing until you need it. The second big plus for this type of rig that again the traction control is just so much easier on the axles and CVs. And the traction control will fit any vehicle - its only the bracketry that will be different.
So if you are going to build a full on comp rig. Is the traction control something you should look at? I would say definately yes especially on the front axle. Most modern rear axles are strong enough to handle a rear locker so a locker there is the best way to go but in the front if you got some bigger tyres and reasonable horsepower then the traction control without a locker will probably make a better rig simple because you will be able to drive it harder without breaking it. On a full comp rig I probably wouldnt run it in the rear because there are times when the time delay of the traction control might slow you down - the lockless doesent have a rear locker and I do notice that its not locked although this hasnt ever stopped me driving anywhere that a rear locked rid has driven (like Tony or Adrian). Most modern rigs do have factory rear limited slip diffs and the traction control working on a limited slip diff is very, very close to a 100% locker. If you are running 35 spline cro mo shafts and CTMs on a Dana 60 then lockers will be best
Sam
But here is a quick run down on how it operates:
We put speed sensors on each wheel which normally consists of a thin steel disc with lots of 12mm holes in it that the speed sensor looks at. This disc just sits in behind the wheel over the studs. The latest way that we are doing this is to place a band of thin steel with the holes in it over the disc brake hub and have the sensor looking at that. The sensor normally mounts off the brake caliper mount bolts. For a drum brake the sensor plate sits on the inside of the drum and so does the speed sensor itself.
The sensors (4 of them) are connect back to a computer that makes decisions about whether it should apply brakes to any wheel.
The way it applies the brakes is by controlling air soleniod valves (like the ARB locker valves). The valves apply air pressure into 4 individual air chambers that apply force to the 4 brake master cylinder that apply the brakes to the 4 individual wheels via the existing wheel brakes. So this is why you need an air compressor to run the system. Also you can see that the individual master cylinder must have an individual brake line running to each wheel brake which is why you need "4 channel" brakes. If you only got 3 or 2 channel brakes (or 1 channel for that matter) then it doesent matter cause you just run extra brake lines and flex lines if needed.
The whole setup is totally tested and ADR compliant and is totally certifiable although at this point each vehicle that the setup is installed on has to be certified individually.
The installation will have to be carried out by trained personel it probably isnt something that you could do by yourselves (although you probably could). In the future it may be because we will make kits for the individual makes so that everything will be a bolt in affair but we arnt there yet.
Sam
When we start selling the traction control setup we arnt going to be trying to compete with the ARB setups on price. Ours is basically going to be priced similarly to the ARBs and we will try to sell it on its performance alone.
Now we may start the pricing a few hundred dollars cheaper than a pair of ARBs to get people looking at the product but I really dont think anybody should buy this just because you are going to save a few hundred bucks. Our traction control has benefits that ARBs carnt offer and it is these features that we will sell it on.
Just as a thought - if our traction control worked identically to a set of ARBs in every situation there wouldnt be any contest because our setup is just so much easier on axles and is so much easier to use. So basically our traction control trades a little bit of top end performance for alot more reliability and strength and ease of use.
So what does this mean in terms of which is better at different levels of wheeling. Heres what i think:
On the mild stuff the performance will be identical - the advantage of the ETC is that you can leave it on all the time and it doesnt effect your turning ability.
As the obstacles get harder there will become a point where you will notice that the full lockers start to work better. This wont necessarily mean that something with traction control wont drive an obstacle that a fully locked rig will but the traction controlled rig will definately have more wheelspin. On an abstacle that can be totally crawled with zero momentum the results would be almost identical in all situations. The lockers may have an advantage in certain situations where you want absolutely no wheelspin where the traction control will let a wheel spin a bit and this will push you off line (and you will fall off a rock and diff out for example) And the traction control will have an advantage in situations where the lockers bind the wheels up and they fight each other (like stuff where you need articulation or really sharp or undercut ledges) With the ETC the drive train will load up less (cause there isnt any binding loads) and the rig will crawl more easily.
As the obstacles get harder again the advantage definately swings back to the traction control simply because its just so much easier on axle components. This lets you drive harder without breaking. When we talk about this sort of wheeling the major application of the traction control is in the front axle because the rear axle will generally be able to handle a locker. That being said the Lockless doesent have any lockers at all and there are only a very small number of situations where a rear locker would make it better - and again there isnt an obstacle anywhere that the Lockless hant been able to drive that a fully locked rig has. This strength issue is the reason why Adrian (POS) runs the traction control on his front axle and not a locker. We have talked about it many times whether or not he would be better off with a locker in the front and he has never done it simply because he knows that his front axle just wouldnt be able to handle it. Basically his rig is more capable without a front locker - and if he can sort out a way to keep his rear end from breaking he would be unstoppable (he has now broken both rear toyota 60 series axles - so I think thats 2 front CVs and 2 rear axles he has broken since it was built which really demonstrates how strong his front combo really is). The other example is the climb that the Lockless has driven Tony has broken twice on and has yet to drive it. For me the climb isnt really all that hard (Im not sure if this is how I should describe it cause it took me about 10 goes to get it and I did roll completely over at one point although I was being fairly stupid on that attempt). Its got a tough ledge at the bottom and it is steep and a bit loose and off camber as you go up. For me its just a matter picking a line and holding the throttle flat. For Tony he just basically has trouble breaking the front end becuse its locked -its happned twice now. Im sure he will be able to drive the climb but each time he tries he is really risking breaking his front end. It wouldnt supprise that i would be able to drive up there 10 times without breaking and Tony would probably break 5 times - I dont know he may not ever be able to drive it without breaking. If he had the same front setup as me I dont think he would have any trouble. Now as our tracks become harder and harder this is going to become a greater concern to Tony - trying to drive stuff and trying to keep the front from breaking. For me and Adrian we dont worry about the strength of the front axle - we do break stuff eventually but it happens over a period of time that we can live with. For Tony if he is not carefull he could break a brand new CV every time he goes out.
So who do I think should buy traction control instead of lockers?
- somebody who isnt into the hard core stuff that wants something that is easy to use and gentle on drive train components.
- somebody that carnt get ARBs for their vehicle.
- somebody that has independent front suspension and doesent want to break it.
- somebody that is really into the hardcore stuff and is having strength issues (espesially the front end)
And who do I think should stay with the lockers?
- somebody that doesent run big tyres that doesent really drive that hard.
- somebody that doesent mind fixing broken CVs.
Sam
