[Hotter]

Hi, I am thinking on getting 335is with 7DCT (GS7D36SG), but I was wondering is it really faster than 6AT (ZF6HP21)?

• Lets say if you are driving regularly in 4th gear (I assume DCT will prepare next higher gear?) and then you floor it, so it would need to lower instead of increasing gear, would 6AT (ZF6HP21) react faster in such case?
• Lets say if you are cruising in 7th gear low RPM and then you floor it, so it would need to lower more than one gear, would 6AT (ZF6HP21) react faster in such case?

Is DCT only faster if you drive 0-60, but not when you suddenly decide to overtake and kickdown is needed?

[whyzee125]

Originally Posted by Hotter

Hi, I am thinking on getting 335is with 7DCT (GS7D36SG), but I was wondering is it really faster than 6AT (ZF6HP21)?

• Lets say if you are driving regularly in 4th gear (I assume DCT will prepare next higher gear?) and then you floor it, so it would need to lower instead of increasing gear, would 6AT (ZF6HP21) react faster in such case?
• Lets say if you are cruising in 7th gear low RPM and then you floor it, so it would need to lower more than one gear, would 6AT (ZF6HP21) react faster in such case?

Is DCT only faster if you drive 0-60, but not when you suddenly decide to overtake and kickdown is needed?

DCT shifts significantly faster than the auto, it's very noticeable. I would think that even in the weird case that you're describing if you had to drop 2 gears, the DCT will still be in the lower gear and accelerating before the auto would.

[CarAbuser]

Yeh it's really next level with the DCT. It's not only a lot faster and more efficient and putting the power down it also has the benefit of making some great noises durihg shift.

It's pretty fast stock and gets a little better with xHP stage3 but I've been using the M3 GTS flash on it recently and that steps things up to another level.

[iqraceworks]

My 6HP21 shifts pretty fast with the XHP stage 3 tune. Knocked out a 10.90 in the 1/4mile.

You are talking about fractions of a second as far as shift speed goes..... it's probably more a matter of power and "driver mod" as far as what's faster....the HP21 vs DCT...

[rjahl]

Originally Posted by iqraceworks

My 6HP21 shifts pretty fast with the XHP stage 3 tune. Knocked out a 10.90 in the 1/4mile.

You are talking about fractions of a second as far as shift speed goes..... it's probably more a matter of power and "driver mod" as far as what's faster....the HP21 vs DCT...

Depends on how you measure fast. I don't race but the DCT is phenomenal.

Best way to learn the difference is to drive the two back to back. I recently drove my Z4 35is to a dealer to test drive a new z4 340 with the 8 speed ZF. The auto is fast but just not in the same league as the DCT. My humble opinion.

I'm not talking about 1/4 mike speed, just driver engagement and fun.

[iqraceworks]

If you want driver engagement and fun....go with a manual. 👍

[Hotter]

I got worried of switching to DCT after reading xHP wiki:

While its raw up-shift performance is unparalleled, it has its drawbacks regarding daily driving, compared to the 6 and 8-Speed Torque Converter transmissions. For instance, spontaneous downshifts over multiple gears in a cruising situation are much quicker on 6HP and 8HP

https://rbttuning.atlassian.net/wiki...Custom+Options

I hope DCT is faster in all scenarios including spontaneous downshifts when overtaking as transmission lag in such situations is most annoying.

[Saif2018]

Originally Posted by Hotter

I got worried of switching to DCT after reading xHP wiki:



https://rbttuning.atlassian.net/wiki...Custom+Options

I hope DCT is faster in all scenarios including spontaneous downshifts when overtaking as transmission lag in such situations is most annoying.

https://www.thedrive.com/news/38715/...even-in-m-cars

There's pros and cons to all transmissions,

The ZF8 used in the M cars is pretty much as fast as the DCT, its smoother and more efficient and probably handle more torque

Saying that a tuned DCT is the next best thing to a manual transmission for driver engagement.

[sbmws]

Originally Posted by Saif2018

https://www.thedrive.com/news/38715/...even-in-m-cars

There's pros and cons to all transmissions,

The ZF8 used in the M cars is pretty much as fast as the DCT, its smoother and more efficient and probably handle more torque

Saying that a tuned DCT is the next best thing to a manual transmission for driver engagement.

This but it also comes down to the type of driving you want to do

If you just want to go fast in a straight line then I dont think you will notice the difference between the 2 as much but if the road is a twisty back or mountain road or you want to track the car then the DCT is going to win hands down for driving enjoyment and feel (with a proper manual being better still)

Ive got a 335 Auto with XHP Stg 3 and a TTS with a stock DCT, I wish the 335 had a DCT

[NoGuru]

Having flashed several tunes to my DCT I can say it is a lot of fun.
The downside for me having lots of mods is the cost of the DCT. I have changed the fluid in mine twice in the last 30K miles and the first time I had a shop do it. The bill was $2000 for the filter and fluid change.
Also I am at about the max for power on stock clutches, around 600whp even with the increased line pressure.

So for me, I only drive this car on nice days or to race and the DCT wins there.
If I was to daily the car or go for really big power, I would want the Auto or manual.

[CarAbuser]

Originally Posted by NoGuru

Having flashed several tunes to my DCT I can say it is a lot of fun.
The downside for me having lots of mods is the cost of the DCT. I have changed the fluid in mine twice in the last 30K miles and the first time I had a shop do it. The bill was $2000 for the filter and fluid change.
Also I am at about the max for power on stock clutches, around 600whp even with the increased line pressure.

So for me, I only drive this car on nice days or to race and the DCT wins there.
If I was to daily the car or go for really big power, I would want the Auto or manual.

People holding 1000whp on stock clutches. Higher potential than the 6HP by a long shot.