[gsfent]

Unless BMW is making up special ring and pinions or has a bunch of 2.93's laying around (what car takes a 2.93?), 3.62 makes sense. I assume (but do not know) they are using the same diff housing.

Since it is clear the gearing has been played with, a little stiffer 1st and a little taller top, it doesn't make much sense to also dramatically change the ring and pinion also.

I suspect C&D is right on this one and someone in the PR department didn't catch the typo on the brochure. Maybe next time they will run the PR past the engineering department!:grinyes:
Regards,
Jerry

 

[gsfent]

Just another couple of thoughts on this. Gear ratios are fixed and "should be known" numbers. Tire math is approximate because of variations in tire size even given same specs and tire pressure variation. Analog tachometers are not precise. Our individual interpretation of a tachometer reading is variable (eyesight, parallax).

We do the best we can

Well, assuming 27 inch diameter tires, 3.62 ring and pinion and top gear of .87for 6 sp and .83 for SMG, you get 26 mph per 1000 rpm and 27 mph per 1000 rpm. At 3000, 6 sp is at 77, SMG at 80.
I can do any speed and any set of variables to confirm gps speeds. 4th in 6 sp (1.19) is real close to 5th in SMG (1.16), so maybe someone can make runs in those gears and compare. They should be very close if both cars have the same ring and pinion.
Regards,
Jerry