I'm wondering if the 4x4 system sends any power/traction to the rear wheels during driving in dry conditions. Is it 100% 2wd in the dry or is some power always sent to the back wheels, 5-10 % maybe?

If the spilt in the dry is let's say 90/10, then the car does have permanent 4wd one could argue. If 10% to the rear, then the system should be ready for slippery conditions without having to spin the front wheels first, before the rear wheels kicks in.

Presuming the Octi system is the same as the Yeti, then yes there is always a small percentage of drive to the rear axle.

 

The system is said to be "pro-active" not "re-active" so apparently can sense "slippage" before it happens. To be honest with the Haldex 4 system it is so fast you would never know, and although the 5 system is said to be marginally slower to react you are only talking microseconds.

 

Don't worry about it; it works, bloody well!

As far as I know in normal driving, dry conditions the ratio is 96% front :4% back. Should you floor your foot, the system will recognize the front wheels are losing traction and the back wheels will engage - up to 50:50.

 

In any case, if you want to spin your front wheels in the dry, you wil have to put some effort

There are a number of reports from the Scandinavian forums that the 5th generation is actually noticeably slower to react than previous generations and Borg Warner have stated that this unit was designed to reduce costs for them (and help increase mpg - not through how it operates but by the fact it's now lighter) but I'd be really surprised if you noticed the difference in normal driving circumstances. Gen 4 runs between 4-10% to the rear in normal dry road circumstances (no incline/gentle throttle use) and is ready to go from the off with drive to both axels. I think this got dropped from the gen 5 system (iirc it was noted on a Scandinavian Volvo forum where someone was comparing his 2013 XC60 against his 2012 XC60). Think the function was referred to 'instant' traction - think it was dropped to help co2 and mpg ratings and Infact if true, this is one feature I'd be sorry to loose as the generation 2 car I used to have used to have to experience wheel slippage at the front before it sent power to the rear. Having read of the issues however, I have to say that my 2nd gen car gave enough outright traction for any circumstance so it could all be considered a little irrelevant.

You get more rear drive than you might realise, as the system is reacting to all types of driving. For example driving up hill, then more power will go to the back wheels.

 

The following vid discribes the Golf VII system but it is the same set up as the Octy III;

 

http://www.youtube.com/watch?v=9apQu8lpPE4

 

 

TP