I lately had a Wavetrac limited-slip diff put in on my 6-speed M240i, which included a ratio change from the inventory 3.08 to three.46. Though the automotive drives fantastically after startup, I’ve ran right into a peculiar problem quickly after the automotive begins. It must be famous that the automotive is bone inventory apart from the diff and an consumption, and there is no check-engine gentle or warnings from iDrive. I all the time drive in DSC OFF, so it is possible not traction management associated.
When the automotive is first began, chilly or not, I lose acceleration in-gear after a couple of second. The turbo will begin spooling and the automotive will speed up usually for a second, however instantly reduce energy after, even when the fuel pedal is pressed to the ground. The automotive will nonetheless speed up, however at a painfully gradual price, virtually unsafely gradual. If I let off the fuel and ground it once more, you’ll be able to really feel a momentary blip of energy earlier than it cuts once more. When you look in Sport Shows on iDrive, it exhibits a really low energy quantity, indicated the ECU is aware of precisely what it is doing. If I shift gears, whether or not upshifting or downshifting, the automotive will behave usually once more for a second earlier than the identical conduct returns. I am unsure precisely what causes the conduct to go away, however the automotive will abruptly start behaving precisely as anticipated between 10-60 seconds after starting a drive.
I referred to as my mechanic who put in the diff, and described the conduct to him. He’s uncertain what induced this, as he mentioned the engine methods have been untouched, which is sensible. Our main idea is that the ECU is confused by the wheel pace not matching the anticipated RPM as a result of new axle ratio, and reducing energy in an try to diagnose the problem. I discover this very possible, as I’ve seen the ECU reducing energy if I’ve extreme clutch slip throughout an aggresive gear shift. Maybe the automotive is making an attempt to stop what it perceives as clutch slip? My different idea is that it has to do with some sensors within the suspension. To put in the diff, the store needed to disconnect your complete rear multilink suspension system, and so they changed a bent entrance management arm unrelated to the diff.
I would love to listen to from another discussion board members who could have had this problem, and the way they fastened it in the event that they managed to. I do know that, even amongst homeowners who swap in a limited-slip diff, the ratio change is rare, so I do not anticipate finding any stable conclusions.
