DCT vs 6AT (daily driving)

[Tag]

Hey guys, I posed this question on the 3 forum, but haven't gotten as many replies as I would like. So knowing there a lot more 1 Series cars then 3's that already have DCT I figured I would ask here to get a better response.

I'm about to get a great deal on a 335is and wanted to know from anyone that has driven both DCT and the 6AT how the DCT compares. I know it's awesome but what I'm looking for is more of the daily driving. Is it just as smooth as the automatic in normal driving? Is there any jerking or abrupt lurching forward with this transmission? Would I know it's DCT if no one told me? I'm planning on test driving one soon but want to hear what others have to say.

TIA

[oman135]

DCT all the way !
i have driven step and i have the DCT its very smooth when driving normal there is no jerking.

[jsublime]

You won't regret the DCT, it is very smooth in D mode. You'll be surprised how quickly you get to 7th even under light acceleration around town.

[MarkR171]

DCT is actually MORE smooth imo. I test drove a step 135 before getting my DCT.

You would know if it's a DCT if no one told you. The shifting is noticeably faster. Especially when driving spiritedly or at full throttle in sport/manual modes, it's a night and day difference no matter how much Step owners say "it's only .2 second difference!!!" You absolutely can tell.

The only time you won't be able to tell the difference between Step and DCT is when the DCT is set to it's most tame setting: D with no Sport button.

[GaryS]

I gave you my opinion on the e90 forum, but I will say it again here. I spent a day swapping between a 135i with DCT and a 335i with Step for autocross. DCT does manual downshifts much better than 6AT, but it does weird hesitations on launch even in Sport mode with DSC completely off. Except for the manual downshifts, I didn't notice any difference in smoothness, but I wasn't really thinking about it, so who knows.

[Tag]

What do you mean by launch? Are you saying when you are at a stand still with your foot on the brake and when you lift off it hesitates?

[JimmyT]

Test drove a 335is w/ DCT and it was fantastic! Bought a 1er with DCT and will never go back. Transmission keeps the engine on boost between shifts, and is much smoother shifting than my VW with DSG.

[MarkR171]

I think he means: if you're standing still, and floor the gas pedal. There's a slight delay, then the car goes. That has to do with the software, and it's really not a problem since I personally can't think of a time I need to floor the pedal from a stop like that without using launch control. I never even noticed it until someone pointed it out and I went out and tried it.

The only time you would ever need to do that is racing between stop lights, and well, that deserves a anyway

If you legitimately need to "launch," there is launch control, and I've already proven you really only need to drive less than a quarter mile before it's available again.

[Tag]

So this is not an issue if you use launch control? It only happens when your on your brake and then floor it and release the brake? Or does the hesitation happen when you are off the brake and floor it? So confused...

[MarkR171]

Basically, let's say you're stopped at a stop light in drive. Light turns green, you take your foot off the brake, and floor the accelerator. There will be a half second delay, then the car will accelerate at full throttle. I think this happens because the software isn't expecting the sudden full throttle.



What launch control does, is it let's you keep your foot on the brake and push the accelerator fully at the same time to raise the RPMs (to a set level) without moving. Then, when you release your foot from the brakes, your car launches forward at that rpm with no hesitation. Basically a racing launch.

[Tag]

OK, that makes sense. So it sounds like if I lift off the brake as normal (without WOT) it moves without any hesitation or jerkiness just like the regular AT. Only time it hesitates is when you floor it without launch control.

[MarkR171]

Right, every day driving, in D mode, it will drive exactly like an AT. You won't notice a difference.

D = feels just like a 6AT
Sport button = quicker shifting than step and higher rpm before shifts
S (Lever to the left) + Button = even quicker shifting and even higher rpms before shifts
M (Lever to the left and manual shifting) + Button = throttle does not lift on upshifts at all, it's that quick!

[Tag]

^ That's the answer I was looking for. Can't wait to test drive it. Thanks!

[GaryS]

^^ No, that's not what I meant. No matter what I or the other driver in the car with me tried, the 135i with DCT did weird hesitations around 5-10 mph, making the 335i Step significantly smoother and quicker to 30 mph. We drove these cars at the BMW Performance Center in SC, but it is still possible that something was wrong.

[MarkR171]

Possibly the self learning transmission, did you try resetting it? Mine has no hesitation when already in motion ~5-10mph.

[GaryS]

Haha, I don't know how to reset it. I also don't know how to do the launch control you mentioned. I tried flooring it with and without the brake and I tried modulating. But really, listening to me compare Step and DCT is like listening to someone compare BMW to Porsche MTs who doesn't know what heel-toe or double-clutch are.

[eleven11]

DCT is smooth in D - it will go to 7th gear @ 40mph with casual take offs. If you're in D mode, it will not jerk/jump (I know what you're referring to).

[supafly323]

You can tell the DCT is a manual at times, even in "D" mode. For example, my 135 has a tendency to roll back slightly when I release the brake from a stop on an uphill slope. My 06 E90 (Step) never did that. I also have to physically press the throttle in reverse to get the car moving from a stop. Again, a difference from my Step.

As far as "D" mode, I agree with other posters that it is similar to Step. I think D mode on the DCT has much better throttle response, however. I find that I can use the throttle to hold it in lower gear much better if I am trying to pass someone around town, and don't want to shift into M mode.

[sparoz]

When I test drove them back to back, DCT on 335i and Step on 135i, I felt the DCT was smooth at D and faster in M mode. I know some people still have issues with DCT and MDCT. Hopefully, they are going to put precog in their next gen like the MP4-12C.

[Tag]

^ What DCT issues are you referring to?

[Tag]

Saw this review of DCT which makes me weary of getting it. Is this really how it is taking off from a standstill or do you think it's driver error?

http://www.e90post.com/forums/showthread.php?t=433737

[CMSS2000]

Maybe DCT works better with N55. Maybe 135i is BETTER than 335is :>)