Thread: CDL wire cut - Finally!

Pics mate?

Cheers

Originally Posted by Alex 110

Since I got my D2 with a Davis CDL activator I've been doing the "CDL Shuffle" when using low range (activator only locks in low range) but I've now cowboyed up & cut the wire to the SLABS ECU. Its great being able to keep TC after turning the engine off without having to play around to get it back.
Best mod so far (by me)

Of course, a SRD500070 would have been a real improvement. I keep trying to tell people...

Mate aside from not having to cut a wire (pretty simple to do) what is the advantage of this - especially if the ealier unit was more aggressive on biting the brakes...you would want that even with CDL to assist traction I would have thought?

Cheers

Originally Posted by ozscott

Mate aside from not having to cut a wire (pretty simple to do) what is the advantage of this - especially if the ealier unit was more aggressive on biting the brakes...you would want that even with CDL to assist traction I would have thought?

Cheers

You mean apart from improved abs programming, better tolerance of low abs sensor output (which elimates a fairly common cause of the amigos), improved etc programming in both high and low range?

Wabco's docs indicate that higher wheel slip allowances (ie less aggressive etc) improves traction in low grip conditions. I'm guessing for most use that is when you really need etc.

Originally Posted by OffTrack

...

Wabco's docs indicate that higher wheel slip allowances (ie less aggressive etc) improves traction in low grip conditions. I'm guessing for most use that is when you really need etc.

Thanks mate - Im not sure i understand how allowing more wheelspin, for eg climbing a slippery clay slope where say 2 wheels are really not getting any grip allows for more forward motion compared to the situation where they are braked aggressively to throw drive over.

Cheers

It's perhaps not quite as straight forward as that. I don't think anyone knows for sure exactly how it has been changed, except for LR engineers, but the ETC does kick in less on loose surfaces that it did with the old SRD000070 ECU. I don't notice any additional wheel spin. I have noticed the ABS performance improvements which seem a bit less scary on loose surfaces. The brake pedal feel improved also.

I think one of the issues that had been raised by a forum member is that loose surfaces don't necessarily have uniform grip. If you have forward momentum it is entirely possible for a wheel to have moved from a having no grip to a surface with some grip before the ETC applies brakes. This potentially results in wheel being braked when it has grip, reducing momentum. Raising the slip threshold by a few percent might help a little in these situations - but that is speculation.

The programming for an unlocked CDL attempts to balance torque between front and rear axles and treats wheel slip on any single wheel as if it has the potential to stop forward motion, applying braking accordingly. The cdl locked programming on the later ECU's changes this behaviour and only monitors for wheel slip across axle pairs. With the CDL locked a single wheel losing traction is not a serious of a problem as you obviously have grip on the other axle.

In the case of a wheel spinning on each axle ETC will act in the same way as it always has. In the grand scheme we are likely talking about a change of at very most 5-10% difference in slip. Putting this in perspective if the threshold with the wire cut is a wheel spinning at 10kph, the revised programming might raise the threshold to between 10.5-11kph.

TBH you don't see too many D2a owners bemoaning the appalling ETC in their cars and demanding the system be to switched back to pre-facelift behaviour.

cheers
Paul