New Mod

[MVF4Rrider]

Originally Posted by epbrown

Here's a comparison chart I made after doing the 3.91 swap on my Z4M (left out the decimal on drag coefficeints). The Z4M is already a pretty good performance bargain, but the gears put you in some pretty exalted company in terms of acceleration, if not handling and top speed. I agree with MV about the flywheel, which seems really heavy in these, but I'll wait to do that when I have to go in for something else:

I would add to your comparison... 1) High average whp (average whp from mid rev to redline). 2) power to weight ratio based on the high average whp value. For example, the high average whp for the Z4 M is 271.2 whp. For the E92 M3, it's 329.9. Whp to weight for the Z4 M is 98.0 whp per 1,000 lbs. The M3 is only 100.6 whp per 1,000 lbs. This shows that a Z4 M's power (across the upper rev range--averaged) to weight is not far off from a new M3. Building revs quicker (ie, 3.91 gearing) will make up the acclereration gap and then some as you well know.

[Dammmittt]

Originally Posted by O-cha

And I thought the car was short as it is.

Top speed with 3.91 gears should be about 186 in 6th...seems long enough to me.

http://www.bimmerfest.com/forums/sho...74&postcount=8