Thread: 1M or M2C
View Single Post
      06-13-2018, 03:22 AM   #20
10"
Colonel
10"'s Avatar
No_Country
4946
Rep
2,260
Posts

Drives: orange BMW 1M.
Join Date: Jun 2018
Location: world

iTrader: (0)

Quote:
Originally Posted by T1M View Post
My main issue with the 1M is the unpredictable VLSD. It is not a normal plated clutch type LSD and it's ability to lock depends on the viscous section first shearing a fluid by differential wheel speeds across the rear axle. This causes the fluid to expand and force a piston against the plates, locking the diff. However once locked, the fluid contracts and the diff unlocks, then a wheel speed difference again must exist to re-lock the diff.

This locking/unlocking characteristic being based purely on wheel speed difference is appropriate for traction on variable friction surfaces like patches of snow or ice but is unpredictable and inconsistent when driving spiritedly. Usually a plated LSD works by locking more or less based on torque applied to the diff, either acceleration (1-way) or deceleration (1.5-way or a more aggressive 2-way).

To me, despite the analogue feel and design of the 1M, the unpredictable diff is a very poor match for a short wheelbase car with a high-torque 3L turbo engine. It makes it a fun ride/wild/angry car but in actual performance/handling terms it's lacking vs the newer BMW M's using the new active LSD's.
Quote:
Originally Posted by T1M View Post
My main issue with the 1M is the unpredictable VLSD. It is not a normal plated clutch type LSD and it's ability to lock depends on the viscous section first shearing a fluid by differential wheel speeds across the rear axle. This causes the fluid to expand and force a piston against the plates, locking the diff. However once locked, the fluid contracts and the diff unlocks, then a wheel speed difference again must exist to re-lock the diff.

This locking/unlocking characteristic being based purely on wheel speed difference is appropriate for traction on variable friction surfaces like patches of snow or ice but is unpredictable and inconsistent when driving spiritedly. Usually a plated LSD works by locking more or less based on torque applied to the diff, either acceleration (1-way) or deceleration (1.5-way or a more aggressive 2-way).

To me, despite the analogue feel and design of the 1M, the unpredictable diff is a very poor match for a short wheelbase car with a high-torque 3L turbo engine. It makes it a fun ride/wild/angry car but in actual performance/handling terms it's lacking vs the newer BMW M's using the new active LSD's.
What you've described as a possible weakness is exactly what some of us want!! things like this are exactly one of the reasons why the 1M is such an engaging car to drive. If people are after the "latest tech" then it's not the car for them. If they're after a classic driving experience closer to older M cars then it's absolutely for them...
__________________
don't read this. too late...
Appreciate 0