recently i went for stage 1 on my b48 pre lci , we achieved quite good numbers for the age of the car , but i observed during dyno , the car starts with front wheels spinning then afterwhile rear engage , is that normal ? i scanned the ecu full all modules , no faults at all or differential issues . did also after all the rear differential servicing with fresh oil .

any suggestion ?

 

Yes, that is normal. The All4 system is "on demand", meaning that the rear wheels provide traction as required and based on input from the drivertain computer. Various inputs go into the equation including yaw, acceleration, and differing traction between the wheels as measured by the wheel speed sensors. It's a sophisticated system!

 

oh that is perfect mate , i was thinking exactly the same , but the guy who did the tune and at the dyno later , told me maybe there is a haldex issue , but i think he wasn't so familiar with this kind of differential , anyway checked the differential through obd no faults and full servicing the rear one , probably need to do the hung on clutch also ...
at the end of the day , when i floor it , i got full traction that means the rear one engage normal when need it .
i remember at my golf R previous models , used to clean the haldex filter and remove the pump , for peace in mind

 

I also have an Audi TTS, which has the same drivetrain as the Golf R. I’m of the opinion that the All4 system is more sophisticated than the Haldex-based Quattro system on my Audi.

 

nice one mate , photo is good and full of snow proper conditions for the all4 .
dont know its my first experience with the bmw all4 , to be fair system differential underneath it looks quite robust !! compare to VW and for that age of car no leaks , drivewise i can't see anything important for moment , i haven't tried yet on snowy condition.
BUT i heard the Audi VW haldex is more effective generally , but again i cant confirm !