Steptronic ratios and 1st gear use vs DCTs? - BMW 3-Series (E90 E92) Forum

Fun w/N54 · 01-18-2013, 01:23 PM

I had a 08 135 with 6MT for 4 years and loved it. Spent the last year with my 09 335 xdrive 6AT and has been 'almost' as equally rewarding. Except that it is effectively a 5AT since it starts out in 2nd gear. I know this unit is used in few other non-BMW applications and can only assume the ratios were not selected by BMW? I recall reading that the 6AT cars get a higher rear gear (or is it those with xdrive) vs MT cars as well? Seems odd as 1st gear is basically useless with 6AT.

Anyway so my question is...is 1st gear a useable gear with the DCTs?

Thanks.

themyst · 01-18-2013, 02:01 PM

Not quite sure why you think 1st gear is useless on an xdrive. You should hook lovely.

Fun w/N54 · 01-18-2013, 08:52 PM

Yes I get your point but how often are takeoffs like that needed. N54 w/Cobb can take most cars if needed with 2nd gear start.

Fun w/N54 · 01-22-2013, 01:20 PM

So no one has input on the ratio differences between the two units? Or if the DCT starts in 1st (or 2nd gear like the steptronic) without driver input.

Thanks.

BuraQ · 01-22-2013, 04:00 PM

The DCT N54 does not allow launching in 2nd. You have to launch in 1st and yes the gearing is different from the regular N54.

All 200+ launches that I have done were all in 1st gear with a best 60' of 1.84

Keep in mind the DCT N54 does not have a torque converter

BEAR-AvHistory · 01-22-2013, 06:01 PM

Could be a wording issue with the word “Launch”. The DCT has a launch control capability which as BuraQ states only works in 1st gear. You can however do standing start runs beginning in 2nd gear by selecting it with the paddles or stick when you are stopped.

These starts do not use the “launch control” program which means all the feathering has to be done with the throttle. There is no torque converter you can’t power brake like a true automatic.

In normal driving the DCT starts in first gear all the time unless you pick a different one with the paddles or stick.

335is DCT 4:78 + 2:56 = 7.34
335i coupe 4:17 + 3:46 = 7:63
335i sedan 4:71 + 3:15 = 7:86

Sedan is an 8spd Coupe is 7spd auto

Fun w/N54 · 01-22-2013, 06:22 PM

Makes sense...thank you both for the info.

01-18-2013, 01:23 PM	#1
Fun w/N54 Second Lieutenant Drives: E92 335i X-Drive Join Date: Apr 2011 Location: WI Posts: 214 iTrader: (0)	Steptronic ratios and 1st gear use vs DCTs? I had a 08 135 with 6MT for 4 years and loved it. Spent the last year with my 09 335 xdrive 6AT and has been 'almost' as equally rewarding. Except that it is effectively a 5AT since it starts out in 2nd gear. I know this unit is used in few other non-BMW applications and can only assume the ratios were not selected by BMW? I recall reading that the 6AT cars get a higher rear gear (or is it those with xdrive) vs MT cars as well? Seems odd as 1st gear is basically useless with 6AT. Anyway so my question is...is 1st gear a useable gear with the DCTs? Thanks.
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01-18-2013, 02:01 PM	#2
themyst Major General Drives: E90 335i LCI Join Date: Feb 2009 Location: NYC Posts: 6,326 iTrader: (8)	Not quite sure why you think 1st gear is useless on an xdrive. You should hook lovely. __________________ E90 LCI N54 6AT

01-22-2013, 04:00 PM	#5
BuraQ Colonel Drives: 11" E92 335is Join Date: Nov 2010 Location: Florida Posts: 2,289 iTrader: (0) Garage List 2011 BMW 335is [3.27]	The DCT N54 does not allow launching in 2nd. You have to launch in 1st and yes the gearing is different from the regular N54. All 200+ launches that I have done were all in 1st gear with a best 60' of 1.84 Keep in mind the DCT N54 does not have a torque converter __________________ ET 11.78 @ 116 Mph, RENNtech tuning, aFe Stage 2 Elite intake (open cover), cP-e Downpipes w/ High Flow Catts, Dinan FMIC, Dinan Axle Back Exhaust, Full Weight, No meth, No DRs YouTube

01-22-2013, 06:01 PM	#6
BEAR-AvHistory 335is 7DCT/JB4-G5/ISO Drives: 2011 335is/JB4-G5/ISO Coupe Join Date: Jun 2011 Location: NC - USA Posts: 1,345 iTrader: (0)	Could be a wording issue with the word “Launch”. The DCT has a launch control capability which as BuraQ states only works in 1st gear. You can however do standing start runs beginning in 2nd gear by selecting it with the paddles or stick when you are stopped. These starts do not use the “launch control” program which means all the feathering has to be done with the throttle. There is no torque converter you can’t power brake like a true automatic. In normal driving the DCT starts in first gear all the time unless you pick a different one with the paddles or stick. 335is DCT 4:78 + 2:56 = 7.34 335i coupe 4:17 + 3:46 = 7:63 335i sedan 4:71 + 3:15 = 7:86 Sedan is an 8spd Coupe is 7spd auto __________________ Kevin 2013 135is Cab 6MT - 2011 335is JB4/ISO - 2010 BMW X3 - 2009 V-Star 2009 Ford Expedition EL 4X4 - 2003 Xterra 4X4 - 1998 Ranger 4X4 Last edited by BEAR-AvHistory; 01-22-2013 at 06:26 PM.

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01-18-2013, 08:52 PM	#3
Fun w/N54 Second Lieutenant Drives: E92 335i X-Drive Join Date: Apr 2011 Location: WI Posts: 214 iTrader: (0)	Yes I get your point but how often are takeoffs like that needed. N54 w/Cobb can take most cars if needed with 2nd gear start.

01-22-2013, 01:20 PM	#4
Fun w/N54 Second Lieutenant Drives: E92 335i X-Drive Join Date: Apr 2011 Location: WI Posts: 214 iTrader: (0)	So no one has input on the ratio differences between the two units? Or if the DCT starts in 1st (or 2nd gear like the steptronic) without driver input. Thanks.

01-22-2013, 06:22 PM	#7
Fun w/N54 Second Lieutenant Drives: E92 335i X-Drive Join Date: Apr 2011 Location: WI Posts: 214 iTrader: (0)	Makes sense...thank you both for the info.