84E24
Well-Known Member
What are some of the advantages and disavantages of
each transmission. Which is most prefered and why?
New E9 owner looking for info.
each transmission. Which is most prefered and why?
New E9 owner looking for info.
265 CR vs 265/6
- Thread starter 84E24
- Start date
As configured for European use, the CR box came with a tall (like 3.07:1) final drive, so it worked well for the high cruising speeds possible on European highways. This reduced low speed acceleration a little, and fuel economy was not a concern on cars so equipped.
In the US, we don't get to drive 100 mph all day. Lower speed acceleration is more useful (and fun). Mating an overdrive 5 speed to a shorter final drive, like a 3.64, gives you better acceleration and lower cruising speed revs for better fuel economy on the highway. It also lets you lug along in 3rd or 4th gear at any speed between 20 mph and 45 mph, reducing the need to shift constantly in surface street traffic.
A CR box with a short final drive gives you a constant workout stirring gears, and you're still stuck with the 1:1 top gear of the 4 speed you removed. With the wide torque band of the M30, it doesn't make much sense.
Other CR issues -- the "holy grail" factor leads to silly prices. It has a reputation for being weaker than the OD, but that's likely not true -- the CR boxes came behind higher-performance engines, get shifted more, and probably also get abused more.
For my money, the OD box is a better option.
In the US, we don't get to drive 100 mph all day. Lower speed acceleration is more useful (and fun). Mating an overdrive 5 speed to a shorter final drive, like a 3.64, gives you better acceleration and lower cruising speed revs for better fuel economy on the highway. It also lets you lug along in 3rd or 4th gear at any speed between 20 mph and 45 mph, reducing the need to shift constantly in surface street traffic.
A CR box with a short final drive gives you a constant workout stirring gears, and you're still stuck with the 1:1 top gear of the 4 speed you removed. With the wide torque band of the M30, it doesn't make much sense.
Other CR issues -- the "holy grail" factor leads to silly prices. It has a reputation for being weaker than the OD, but that's likely not true -- the CR boxes came behind higher-performance engines, get shifted more, and probably also get abused more.
For my money, the OD box is a better option.
ScottAndrews
Well-Known Member
I run a 265 in front of a 3.07 (as Velocewest noted) on my Euro 635. This was stock fare, but it was pushed by an M90 motor, which ad a lor more power and torque than the 3.5 lter M30, and WAY more grunt than a 3 liter M30.
In this car it works fine. It goes 93 MPH at 3K RPM in 5th, but around town at 35, you find yourself lugging along at 1500 RPM in 3rd, or scaring the bejesus out of your roadmates by whining along at 3.5K in 2nd. The 2-3 gap is pretty wide.
I would not recommentd the 3.07 with a 265 in a 3 liter car. The 3.64 is probably a better bet, and you are not, I assume, planning on tooling along at 130+...
S
In this car it works fine. It goes 93 MPH at 3K RPM in 5th, but around town at 35, you find yourself lugging along at 1500 RPM in 3rd, or scaring the bejesus out of your roadmates by whining along at 3.5K in 2nd. The 2-3 gap is pretty wide.
I would not recommentd the 3.07 with a 265 in a 3 liter car. The 3.64 is probably a better bet, and you are not, I assume, planning on tooling along at 130+...
S
pj
Well-Known Member
I have a cr box in my coupe with a 3.25 lsd ,I am pretty pleased with the performance. The only weakness is the shifter breaking at the weld point. But we seem to have fixed that problem.
PJ
PJ