PaoChe

Thank you for clearing that up. Not many people realize how advanced the ZF transmission in our cars is, especially when you realize that the 7 series was using it in 2001 (might have been 2002, not sure)and it was the first 6spd AT ever used in a mass production car. It uses multiple gearsets, planetary and ravigneaux, with about half the moving parts of a standard automatic, and is able to achieve complete torque converter lock up in all forward gears and has shift times on the order of 200 milliseconds. That's fast.

hooch999

Thank you for that. Based on the response I got it right about auto trans.

hooch999

torque converter lockup clutches have been used since 80's by GM and now standard on all modern slush-boxes. The clutch(es) is actually the root of most problems with bmw slush-boxes due to poor design by ZF they tend to burn out rather quickly causing that famous transmission jerkiness and gear slip.
BTW torque converter lock is only for cruising, once you step on the gas even slightly there is no lock any more otherwise slush-box will not be able to accelerate.

jasperxli

HELL F*CKING YEA!!! JDM IN MY ROOTS!!! i come from an evo 8 and acura cl-s6

tonyscoots84

i tend not to drive step at all. I dont want to mess anything up with the tranny or engine so i keep it in auto. when i get a loaner thats when i use the step.

Blue Magic

1 out of 6 questions answered and the joke was the 1 haha, any more help boys?

Richr8

Ever driven one hooked to the 535 or 550? They're quick. Not quite the slushbox of yester year. I would like to see a comparison.

Razz

Does anyone know where I can find detailed information on the steptronic transmission? IE Diagrams, specs, and all that good jaz would make me much more familier with what I am working with.

On another note, I went the the Tail of the Dragon last weekend and my steptronic transmission did not skip a beat! I was in M mode and constantly shifting and gear braking between 2nd, 3rd, and 4th gears and drove my 550i at constant rpm's of about 3500 rpms. Driving in the mountains of TN and NC with my 550i, using the power ban and the faithful steptronic transmission was nothing less than intoxicating! I truly used the full potential of my car, with DSC on... Have you ever seen those roads?! Granted I would like to have an SAT or MT and I will eventually be playing with the ideah of trading my car for an e90 M3 with a Double Clutch transmission! In my opinion, the only AT's in BMW should be Double Clutch ones but what do I know?

I will be posting pics of my trip to "The Dragon" as soon as I get them in the mail! If anyone could give me a refrence for the details on the Steptronic that would be sweet!

Stay Classy!

Darron.Lowe

Hi John,

I'll try to answer your questions based on my experiences and will attempt to not get caught up in the Manual / Auto argument or who can shift the quickest (Auto with SAT... Damn, couldn't help it )

"So it always starts on M2" - you don't mention the car you have but assume a V8 as I believe they tend not to use M1 (may be wrong!!!)

"on easy days I'll shift it at 2000rpms, when I rip it, 3000 to 3500rpms" - if you are shifting at 2000rpm then there is no point in using the selector... just let the auto do its stuff. Also, 3500rpm is not 'ripping' it! A petrol car has its highest BHP at high revs therefore you are not using anywhere near the full power of the engine.

"when slowing down I just let the computer shift to lower gears" - you can do this, but again you may as well let the auto do its thing. if you are 'driving with enthusiasm' then as you slow down you up shift to keep the engine revs in the sweet spot where the power is. If your car revs to 7000rpm then downshifting at 5000rpm will keep the car at full power (the revs depend on your car)

"Do you start on M1 or just leave it on M2?" - the car selects M2 for a reason so I would personally avoid M1. Others may disagree here though... There are also those who say that pulling away in M2 is no slower than M1, but that could depend on the car. Regardless I doubt there is little difference unless you are pushing the car to its limits.

"What rpm is ideal to shift at?" - for normal driving keep the revs low to keep the engine under as little stress as possible and to save fuel, but for 'spirited' driving then keep in the power band - again this depends on the car you have, but expect this to be at the top 2000rpm (5000 to 7000 for example) - others with your same engine will be able to give more feedback than I can.

"Is it ok to take it all the way to M6 and just cruise?" - If the car doesn't like it, it will change gear so you will not hurt the car by doing this.

"Is it ok to let the computer shift to lower gears?" - as above, just i see little point and would let the auto do its thing!

"Is it ok to shift to lower gears while still stepping on the pedal" - no problem with this, except...

"for instance taking a turn ending up going slower than current gear?" - if you are pushing the car hard, then change gear before a corner. when a car its at its limits of traction, a gear change could be enough to loose traction. Although, I suspect that your driving style will not have this problem

Without wanting to offend, if you do not know when the car has the most power (and i may be misunderstanding you from the above) and when to change gear, then forget the manual shifting and just use the auto. To beat the Corolla, move the lever into D/S (which is it in to allow you to manually change gear) and just plant the right foot hard on the floor and do not lot up until there is a small Corolla shaped dot in the rear view mirror!

I hope this helps!
D

sleeper50

Uh, like an automatic. But always in Sport. Automatic feels like a K car off the line...way too much lag.

hmmmmm, maybe it's time for a sprintbooster......