Haldex droning / vibration

[vanvan]

Hi,

New member in the forum and looking for some help

I own a 2017 FL DAZA with the performance pack (noisy exhaust + reverse staggered wheel size). The car has some awful droning from behind, not the exhaust, something in the drivetrain. The sound is very similar to one associated with cheap exhaust droning, but I'm sure it's not the exhaust in my case, because it is related to cornering.
I think it is something in the haldex or rear diff, because it is emphasized when driving in "slalom" under light acceleration and with 30-70 kph speed. Also, when the car is equipped with four identical tires (my winter setup) the problem is gone. The current tires are the Pirelli Pzero with R02 index, so it should be fine, no?

p.s. The car has been ECU modified, I wonder if that could also contribute?
p.s.2 When I remove the fuse for the all-wheel drive module (incl. haldex) the problem is also gone, but so is my traction

Any ideas?

 

[flybynite]

First of all get the oils changed, front and rear diffs, haldex (clean the gauze filter) and DSG. Check the quantity and colour of oil coming out. Any VCDS/OBD11 codes?

Do you know the history? not first time rear diff oil been drained by mistake on a haldex service.

RO2 tyres are correct but if they are worn more than the backs the difference may be too much but normally that generates traction control warnings.

As it goes away on winters, it might be the tyres saw-toothed, you can tell that by rubbing your hands down the tyres each direction. Have you dried swapping the staggered tyres side to side and run them in reverse? They are sided but non directional so will be fine but offset the saw-tooth.

ECU/TCU flash should not matter but if it has had a haldex controller fitted locked to 50/50 or been launched to within an inch of its life then that will make a difference.

Everything is just better on square setup tyres, it's what I run summer and winter

 

[vanvan]

Thanks for the reply!

I have already changed oils of DSG, Diff and Haldex, the service history also mentions 2 changes in Haldex oil, so in total the oil have been changed 3 times. And yes, the filter on top of the pump was cleaned last time. VCDS scan shows no errors, values of Haldex pump adaptation are within the normal boundaries according to the Haldex specialists website.
RO2 tyres are brand new, I ended bying them since I thought the previous set (Conti Sport 7) were the root cause of the problem.

I've also restored the original ECU maps since last post - no change unfortunately (except now car is slower, due to only 400bhp being delivered )

I'll change to winter tires just to be absolutely sure that squared setup is going to cure the problem. If that is the case then what summer tires to look for for squared setup on the staggered rims?

 

[flybynite]

If the winter tyres cure the problem swap the summers from side to side see if that changes things too. How worn are the rears?

Many use/have used the standard 235/35/19 all round on staggered wheels with no issue. You could use 245/35 as a happy medium.

I turned 2 staggered sets into 2 square sets (4x 8" winter with 235/35 4x 8.5" summer 245/35)

255/30 do fit all round on 8.5" on a saloon but I think they are tight on a SB especially if you go Michelin