crouzer

Has anyone discussed this yet?

Audi says its new sequential transmission is faster than its six speed (0.06 I think).

With a high RPM engine would there be programming for the SMT that could bring your RPMs up when pulling off from a stop similar to doing this with a manual transmission?

Or will the SMT transmission lag from a stand still?

Clue me in! :D Thanks!

tribal azn2

bmw's smg2 is faster then its "regular" manual

crouzer

But don't the power bands on BMWs start in the lower RPM range?

babylou

The SMG2 shifts are faster but acceleration from a standstill is almost always not as fast. The reason is the BMW has programmed in an aggressive launch control for European cars but one is only allowed to use it twenty times over the life of the car or the warranty is voided. How does BMW know? The ECU records each each instance. I guess BMW is trying to reduce driveline stresses.

I like these SMT's but they need more development. All but BMW shift in a minimum 0.2-0.3 seconds which is slower than shifting manually. In addition, without launch control these cars are about 0.4 sec slower to 60 mph.

crouzer

Ahh.. ok, so that is one way they are labeling this type of programming "launch control". Haha

Its good to know that this exist, I agree it would be "slow" without it. Should be required equipment on a high RPM car IMO.

I can see it being hard on a clutch but thats about it. Wonder what the status of aftermarket high performance clutches for SMTs are.

Gord96BRG

Nope, not Audi's new DSG (stands for Dual Shaft Gearbox, with two clutches) - it's faster shifting than anyone's, including BMW's. Also smoother and has less clutch wear, and is faster than the equivalent manual gearbox.

Regards,
Gordon

babylou

I haven't seen any data on shift times for the Audi yet. I do know the concept has good potential because of the preselecting gears but I think there might be a problem with this setup. For instance, when accelerating in say 3rd gear the tranny has preselected 4th gear. Right? Well what happens if while in 3rd gear you approach a 2nd gear corner and 4th gear is preselected? Are the downshifts real laggy or what? Also, how does the tranny reduce clutch wear? Finally, what about standing starts? Is there launch control?

varchild

I thought this might be a problem but then I saw how it is set up each Drive shaft (one nexted inside the other) has three gears one does the odds 1,3,5 and one the evens 2,4,6. So basically if you are in 3rd then whether you are shifting into 2nd or 4th you are still switching to the 2nd drive shaft with only a minor change in selection time slowing down to normal smg-like times but still quite fast and smooth. all of the auto magazines did test drives on the new TT with this gearbox a few months back and noone noticed any lag in sudden downshifts.

Oh and DSG stands for Direct Shift Gearbox not dual shaft gearbox.

DijabutiA

yes, you can do an "F1" start on the DSG gearbox ; you stop and put the car into first, hold the brake and press the gas... the tranny automatically recognizes the stopped car with brake and gas and it will let you launch at 3-4k rpm