a061444

Why is it that the 530i SMG transmission car is .3 sec faster than the Step. transmission car? The both weigh the same. Is it in the speed of the shifting of the SMG is similar to the manual?

From www.bmwusa.com:


Weight 1 Unladen

Manual transmission 3461 lbs Unladen
Sequential Manual Gearbox (SMG) 3483 lbs Unladen
Automatic transmission 3483 lbs

Weight distribution, front/rear
Manual transmission 50.4/49.6 % Weight distribution, front/rear
Sequential Manual Gearbox (SMG) 50.4/49.6 % Weight distribution, front/rear
Automatic transmission 50.9/49.1 %

Acceleration 0-60 mph - Manual Transmission or SMG 6.6 sec
Acceleration 0-60 mph - Automatic Transmission 6.9 sec

heezy545i

speed of shifts and torque converter?

Rmart

Automatics must tap engine power to operate. They sap some of the available HP that a manual does not use. I guess the SMG does not use much or any engine HP to operate. Could be different transmission and rear end gearing also.

a061444

What's also puzzeling is that the weight of the SMG is identical to the Step. but the weight distribution is the same as the manual trans?

Rudy

It's all about the torque converter. Manuals (no torque converter) transmit more of the available power to the driveshaft. Automatics (with torque converter) always rob you of some of the power. It's the nature of an automatic.

Remember that the SMG gearbox is identical to that of the 6-speed manual. It's the clutch that's different...

a061444

But, how do you explain the weight distribution? Where did the weight go up, front and rear?

Rudy

Maybe the automatic transmission weighs more? Maybe it's all the fluid? Hell, maybe the specs from BMW are wrong?

JDN

Hell, maybe Rudy missed his coffee!

skaffa

...or got too much?

Skaffa

Jimbo

probably faster shifts.