Based on this I am guessing that if you have the AWD model you would have to swap both diffs, if that's possible?ken in az wrote: ↑Wed Mar 11, 2020 2:50 pmI did this with my old M45 except it was with a g37 rear diff that had VLSD.
Made a huge difference in acceleration and actually increased my fuel economy in city driving. Highway mpg dropped pretty significantly 2-3mpg.
No codes tripped, car drove great. Traction Control and stability control still worked with no problems. Speedometer on dash read the same accurate mph.
Only problem I had was with the cruise control. It would not set any higher than 64mph. My reasoning for this is because the cruise control works off the output shaft speed sensor in the transmission, which would read that the car is traveling much faster than wheel speed.
At the time cruise control was more important to me than ETs at the drag strip, I swapped back in the stock diff.
If I were you i would look for a g37 diff with LSD. The LSD would be the only reason I change gear ratios going forward. Made such a large impact on driving fun.
PS - I haven't updated my sig in a while, I have a 2011 M56 S now
That's not a g37 diff. The g37 has 4 bolt holes.ken in az wrote: ↑Mon Mar 23, 2020 4:13 pm
This one is 3 bolt like ours. I'm trying to find out how many teeth are on the Tone Ring of the axle stub and to see if the sensor is compatible with our car. I'm 99% sure it is, but if the tone ring has a different number of teeth, then it will throw off the Stability Control/ABS/HICAS all kinds of stuff.
Anyone have access to a G37 axle stub to count the tone ring?
Nah, i checked both coupe and sedan. The MT is 4 bolts and AT is 3 bolts for both types.
After looking closely at this, I don't have the right garage setup to pull this off without getting crazy. Looks like it's gonna be you amigo! I'm very curious how this goes and will be following. I'm a bit confused though, are you using the M37 rear diff or the G37 rear diff. Both have been discussed but it looks like you are putting a G37 diffy into the M56. Correct?