[Proper Motion LLC]

Car....................E90/92 Automatic....E90/92 Manual
Final Drive............3.46.....................3.08
1st......................4.17..................... 4.06
2nd......................2.34..................... 2.40
3rd......................1.52..................... .1.58
4th......................1.14..................... .1.19
5th........................87..................... ..1.00
6th........................69..................... ....87

Steptronic Automatic Shorter Gear Ratios ?

[demosthenes]

Originally Posted by 09AlpineTTSedan

Car....................E90/92 Automatic....E90/92 Manual
Final Drive............3.46.....................3.08
1st......................4.17..................... 4.06
2nd......................2.34..................... 2.40
3rd......................1.52..................... .1.58
4th......................1.14..................... .1.19
5th........................87..................... ..1.00
6th........................69..................... ....87

Steptronic Automatic Shorter Gear Ratios ?

The combined ratios for the 335 are:
....... Auto... Manual
1st.. 14.43.. 12.50
2nd... 8.10... 7.39
3rd.... 5.26... 4.87
4th.... 3.94... 3.67
5th.... 3.01... 3.08
6th.... 2.39... 2.68

The stick does 0-60 in 5.4 and the auto in 5.6 even though the auto has shorter gearing.

Doesn't this prove that the manual is more efficient at transferring power?

[alq80]

Originally Posted by demosthenes

The combined ratios for the 335 are:
....... Auto... Manual
1st.. 14.43.. 12.50
2nd... 8.10... 7.39
3rd.... 5.26... 4.87
4th.... 3.94... 3.67
5th.... 3.01... 3.08
6th.... 2.39... 2.68

The stick does 0-60 in 5.4 and the auto in 5.6 even though the auto has shorter gearing.

Doesn't this prove that the manual is more efficient at transferring power?

im pretty sure both get to 60 in < 5 seconds.. maybe compare two of those results?

[demosthenes]

The 0-60 times are BMW's numbers from the USA web site.

[markinva]

Well, if you believe Car and Driver, then the steptronic is faster... albeit slightly

http://www.caranddriver.com/reviews/...fs+page-5.html

[demosthenes]

To compare straight line performance between auto and stick, we need standardized tests across multiple stock vehicles. The only one in the position to do that is BMW.

[Blue Streak]

Originally Posted by markinva

Well, if you believe Car and Driver, then the steptronic is faster... albeit slightly

http://www.caranddriver.com/reviews/...fs+page-5.html

This is a touchy issue because lots of Steptronic drivers get all worked up and emotional about it. I think BMW is advertising the capability of the transmissions, while Car and Driver is advetising the results from actual driver tests. The big variable there is the driver, of course. It's much easier to operate an automatic transmission than it is to operate a manual transmission effeciently. However, I believe a skilled driver with experience on this BMW manual transmission should be able to shift and put the power down at least just as quickly, but the important message is that those skilled drivers are very few and far between.

[demosthenes]

I agree that this is a loaded issue. I've been reading auto vs manual threads for years. I don't believe there is a right or wrong choice. If you like the manual buy it; if you like the auto buy it.

But I'm curious to find out why the auto has shorter gearing yet it is slightly slower.

[cstavaru]

Originally Posted by demosthenes

But I'm curious to find out why the auto has shorter gearing yet it is slightly slower.

Probably because the torque converter which loses power ? But the combined final gearing (gearbox plus the differential) is shorter for manual from what I see ?

[Proper Motion LLC]

Originally Posted by demosthenes

I agree that this is a loaded issue. I've been reading auto vs manual threads for years. I don't believe there is a right or wrong choice. If you like the manual buy it; if you like the auto buy it.



But I'm curious to find out why the auto has shorter gearing yet it is slightly slower.

I take those numbers with a grain of salt. BMW also says the 335i only makes 300HP...

[Kbueno]

Originally Posted by Blue Streak

This is a touchy issue because lots of Steptronic drivers get all worked up and emotional about it. I think BMW is advertising the capability of the transmissions, while Car and Driver is advetising the results from actual driver tests. The big variable there is the driver, of course. It's much easier to operate an automatic transmission than it is to operate a manual transmission effeciently. However, I believe a skilled driver with experience on this BMW manual transmission should be able to shift and put the power down at least just as quickly, but the important message is that those skilled drivers are very few and far between.

Absolutely correct.
Also, FWIW, please note that the car & driver tests were performed at different dates at different tracks.

[Staszek]

Originally Posted by 09AlpineTTSedan

Car....................E90/92 Automatic....E90/92 Manual
Final Drive............3.46.....................3.08
1st......................4.17..................... 4.06
2nd......................2.34..................... 2.40
3rd......................1.52..................... .1.58
4th......................1.14..................... .1.19
5th........................87..................... ..1.00
6th........................69..................... ....87

Steptronic Automatic Shorter Gear Ratios ?

The Step has shorter gear ratios to make up for the loss of power due to the tq converter as well as the additional weight.

A common practice on the E46 boards was to take the 3.46 diff out of the automatics and put them in 325 manuals to give them better off the line acceleration.

What this does is give you a faster jump off the line but you lose top end power. Its also reduces gas mileage. But it does make a difference. I have a friend who had the 3.46 in his manual 325 and you could tell a big difference driving it around town.

Bmw tends to give a shorter gear ratio to all their autos.

[Insider]

Originally Posted by demosthenes

To compare straight line performance between auto and stick, we need standardized tests across multiple stock vehicles. The only one in the position to do that is BMW.

Very true. And here is BMW showing http://www.bmw.co.uk/bmwuk/pricesand...-bmwuk,00.html that the 335i auto is faster 0-62 (5.4) versus 5.5 for the manual

[alq80]

Originally Posted by Blue Streak

This is a touchy issue because lots of Steptronic drivers get all worked up and emotional about it. I think BMW is advertising the capability of the transmissions, while Car and Driver is advetising the results from actual driver tests. The big variable there is the driver, of course. It's much easier to operate an automatic transmission than it is to operate a manual transmission effeciently. However, I believe a skilled driver with experience on this BMW manual transmission should be able to shift and put the power down at least just as quickly, but the important message is that those skilled drivers are very few and far between.

lool you make the debate between at and mt comparable to a race issue :P funny!

[markinva]

Originally Posted by demosthenes

To compare straight line performance between auto and stick, we need standardized tests across multiple stock vehicles. The only one in the position to do that is BMW.

would you have easily dismissed the C&D article if it had shown the automatic was slower?

well, with all due respect, car and driver has a pretty standardized test procedure- and they correct all data for atmospheric conditions to maintain comparability between different test conditions. I would venture to say that the amount of effort that C&D takes to get acceleration times is vastly greater than what BMW does. manufacturer acceleration times are almost always a token, nominal statistic that is slower than the real time that can be achieved.

Certainly the bmw steptronic that C&D tested may have been a fluke, and BMW may have tested several and found the manual to be slightly faster with their bmw test drivers across several cars. BUT, I believe a FAR more likely reason is that Car and driver brake torques their automatics to the stall rpm when they do their testing while BMW probably doesn't. that's how they got a 4.9 second time, which is much better than BMW's claim.

And about either BMW's claim or C&D's claim, keep in mind we are debating about .2 seconds between manual and step, so really, that's nothing.

now, I'd also note that BMW shows that the xdrive 335 is faster to 60 than the rwd 335i, which is also very misleading.

[Proper Motion LLC]

Originally Posted by markinva

now, I'd also note that BMW shows that the xdrive 335 is faster to 60 than the rwd 335i, which is also very misleading.

Exactly BMW is just telling each driver what they want to hear..

A 6MT Driver wants to hear that his car is faster than the 6AT
A 6AT Driver wants to hear that his car is as fast or nearly as fast as the 6MT.
The 335xi driver wants to hear that his car will get the jump because of AWD.

[Turbomatic]

Originally Posted by Staszek

What this does is give you a faster jump off the line but you lose top end power.

The shorter final gear ratio gives the car more mechanical leverage and puts the rpms higher at a given speed. There is no loss of top end, I think you mean loss of top speed as the car will run out of gearing more quickly. The advantage is that you will be higher in the rpms quicker and therefore take better advantage of the power output in those rpm range(most hp output peaks at higher rpms).

The fuel consumption is a given since your are in essence always reving the car slightly higher than before at a given speed. In many cars the speedo may also be off slightly as the stock speedo is calibrated to the stock final gear. Don't know if this is the case with the BMW.

Final gear changes will place more stress on the engine and trans due to consistently higher rpms and its related issues such as heat and wear on the spinning parts.

0-60 can be affected by many factors so a .2 difference during a particular test isn't really worth getting worked up over. That difference can be caused by colder air versus a warmer day, tire condition, better prepped track surface, Altitude, Humidity, grocery in the trunk, poor maintenance, fat driver, etc.

[Proper Motion LLC]

It's pretty cool that BMW uses shorter gearing (1-4th gear) for the steptronic.

And without the ECU limiting top speed, the steptronic would theoretically be capable of higher top speeds too, correct?

[demosthenes]

Originally Posted by markinva

would you have easily dismissed the C&D article if it had shown the automatic was slower?

well, with all due respect, car and driver has a pretty standardized test procedure- and they correct all data for atmospheric conditions to maintain comparability between different test conditions. I would venture to say that the amount of effort that C&D takes to get acceleration times is vastly greater than what BMW does. manufacturer acceleration times are almost always a token, nominal statistic that is slower than the real time that can be achieved.

Certainly the bmw steptronic that C&D tested may have been a fluke, and BMW may have tested several and found the manual to be slightly faster with their bmw test drivers across several cars. BUT, I believe a FAR more likely reason is that Car and driver brake torques their automatics to the stall rpm when they do their testing while BMW probably doesn't. that's how they got a 4.9 second time, which is much better than BMW's claim.

And about either BMW's claim or C&D's claim, keep in mind we are debating about .2 seconds between manual and step, so really, that's nothing.

now, I'd also note that BMW shows that the xdrive 335 is faster to 60 than the rwd 335i, which is also very misleading.

Even though I drive a manual, I have nothing against the steptronic in the 335i. It seems like a great tranny. Some of us aren't interested in proving that our choices (auto vs. manual, coupe vs sedan, 335 vs 328, leather vs leatherette, jet black vs black sapphire, etc.) are superior. We want to learn more about our cars and share our enthusiasm, not engage in conflict.

I've subscribed to Road&Track and Car&Driver for decades and I like them both. I believe their test results. If they tested "identical" pairs 335i sedans or coupes, some with step and some with manual, on the same day, I'd believe the results.

I think your explanation that C&D revs the steptronic before launch might explain the difference.

But the question remains, if there is no slippage in the step once it's locked up at 15 mph and the shifts are superior to what most manual drivers can pull off, why does BMW put shorter gearing in the steps for first through fourth?

[DrGP]

BMW advertizes that the 6MT is faster than the Step. But hey are using professional drivers. In the real world, the Steps are recording faster times since most drivers cannot shift fast enough to turn optimal times with the 6MT. ALSO, the X drive models are faster than the 2wd models since they have better traction off the line, even though they amy be slightly heavier.

[Blue Streak]

Originally Posted by demosthenes

But the question remains, if there is no slippage in the step once it's locked up at 15 mph and the shifts are superior to what most manual drivers can pull off, why does BMW put shorter gearing in the steps for first through fourth?

Good question...
There are great advantages to both transmissions for different applications. I just like shifting my own gears and using a manual clutch... whether it's faster or slower by less than .2 seconds to 60 doesn't even matter to me. I like the manual. Others like the auto and are very pleased with how well BMW's Steptronic operates and how close or even "better" it may be than BMW's manual. I do like the fact that the 335i's manual is the same one used in the M3 and M5 though.... (from what I've read) which shows that it's pretty strong and should be fairly reliable over time as long as the clutch isn't abused.

[Insider]

Originally Posted by DrGP

BMW advertizes that the 6MT is faster than the Step. But hey are using professional drivers. In the real world, the Steps are recording faster times since most drivers cannot shift fast enough to turn optimal times with the 6MT. ALSO, the X drive models are faster than the 2wd models since they have better traction off the line, even though they amy be slightly heavier.

Except on the BMW UK site http://www.bmw.co.uk/bmwuk/pricesand...-bmwuk,00.html in which case they state the auto 335i is faster than the manual. A bit strange if I do say so myself.