View Single Post
      09-09-2014, 03:05 AM   #18
dcaron9999
Major
dcaron9999's Avatar
Canada
157
Rep
1,409
Posts

Drives: 2011 135i M package
Join Date: Jan 2010
Location: Mirabel, Quebec

iTrader: (0)

Quote:
Originally Posted by flinchy View Post
There's even more than what wanganstyle said

the torque/power curve of a high boost small turbo N54 means you don't shift at redline for max acceleration in gears 3+... more like 6100/6200

by shortening the effective gear ratio of the car, you're increasing how often you need to shift, and reducing the width of your (limited) power band..

there's calculators you can use to simulate it.. but basically, a stock frame (besides the upcoming SUPERRB/VTT2+) at max boost/power will get better acceleration with a 2.56 ratio over a 3.08 or 3.46

however it will FEEL faster going the shorter gearing, even though the reality it's several tenths slower and much harder to control.
Im still loving my Quaife 3.46 diff, and its very smooth and predictable at the track. I assume the MFactory 3.46 LSD is similar. You do have to be smoother with your throttle inputs when turning. If you apply a little too much pedal, you just need to "lift" - its very easy to get it back under control with the LSD ...

Im getting a custom tune done for my Cobb AP3. PTF (protuningfreaks.com) tailors a map specific to your Diff ratio, tire category and tire size. This is interesting and may address what you mentioned about turbo load ...

Im pretty impressed with the way the power is delivered and handled with my Quaife at the track currently, but allways looking for that extra gain and even smoother delivery if possible. Will see how well PTF addresses this for my setup versus OTS maps ...
__________________
2011 X3 35i with M pack + 2011 135i w/6SPMT | 255 square tire setup | Quaife 3.46 LSD | Diff lock down bracket | Bilstein B8+Swift SpecR springs+H&R FSB | CDV delete | BMS Oil Tstat bypass | ER FMIC & CP | N54Tuning DP | GC Street Camber Plates | M3 FCA +guide rods+RSFB's+Tranny mounts | Manzo toe arms | Cobb Stg2 agressive tune | Hawk DTC70 brake pads | RB SS brake pistons | Goodridge SS brake lines | Custom brake cooling ducts
Appreciate 0