SMG vs DCT

[cringle]

Hi guys, I previously owned an E46 M3 SMG, and have put my name down for the forthcoming M4. I think I'll go for the DCT option, its going to be the same 7 speed dual clutch gearbox in the E9X carried over. I've never driven the E9X DCT, just wanted to ask about its characteristics...ie does it give complete control and hold the gear like the smg without automatically changing up? Or does it act like VAG DSG gearboxes and do what it likes?

[martin mrt]

No it's not like the DSG, it will hold a gear all the way to the limiter, and stay in gear

I love the DCT in my M3, I wouldn't want a manual after trying one

[cringle]

Thanks pal. DCT it is then!

[HoHoHo]

However, in my 335i it would change at the limiter rather than simply bounce off it as PDK does in a 991 for example.

My point being it's still thinking for you to some degree rather than PDK which can be totally controlled by the driver.

[cringle]

Ok now i'm confused. Are the gearboxes programmed differently in the 335i and M3? Does the M3 bounce off the limiter or change up for you?

[djtex]

cringle said:

Ok now i'm confused. Are the gearboxes programmed differently in the 335i and M3? Does the M3 bounce off the limiter or change up for you?

You are correct, they are configured differently. DCT in my M3 will bounce off limiter in manual mode, also it gives perfect rev-matched downshifts which I don't think it does in the 335i either.

It's a great gearbox.

[Babw]

DCT changes gear effortlessly with no drama at any road speed. No delays, no thumps just foot flat changes or smooth auto, in town etc

You know what the SMG is like.

Which is the better gearbox....that's debatable.

[JapFreak786]

DCT is a million times better than SMG imo, had SMG in my E60 M5 and it was ok at the time I thought.

Now i have an E93 M3 with DCT,brother has an E46 M3 with SMG and they are night and day apart, DCT all the way IMO,manual wouldn't even cross my mind.
I find myself getting frustrated to an extent in his M3 when I drive it, gear changes feel like an eternity

[waremark]

My DCT E92 M3 will bounce of the rev limiter - has only happened about once in 64k miles! The DCT box is very similar to the PDK - but it has two control advantages in my opinion, you get paddles as well as a multi-function wheel (in Porsche's you have to choose one or the other) and the lever in the centre of the car is forward down, backward up, which is opposite from all Porsche's except the new GT3. Perhaps Porsche have decided they were wrong about the way that worked!

The DCT is brilliant, but I rather miss the satisfaction of using a clutch pedal and making accurately rev matched gear changes without a computer to help, and managing to fit manual gear changes into the drive without damaging the flow of the drive.

[MerseaBoy]

djtex said:

cringle said:

Ok now i'm confused. Are the gearboxes programmed differently in the 335i and M3? Does the M3 bounce off the limiter or change up for you?

You are correct, they are configured differently. DCT in my M3 will bounce off limiter in manual mode, also it gives perfect rev-matched downshifts which I don't think it does in the 335i either.

It's a great gearbox.

I think the M3 and the 335 have different boxes. Only the M3 has DCT, the 335 is a full autobox i believe.

[HoHoHo]

MerseaBoy said:

djtex said:

cringle said:

Ok now i'm confused. Are the gearboxes programmed differently in the 335i and M3? Does the M3 bounce off the limiter or change up for you?

You are correct, they are configured differently. DCT in my M3 will bounce off limiter in manual mode, also it gives perfect rev-matched downshifts which I don't think it does in the 335i either.

It's a great gearbox.

I think the M3 and the 335 have different boxes. Only the M3 has DCT, the 335 is a full autobox i believe.

My 2011 335i had a DCT box (7 speed), but clearly not programmed as the M3.

Previous E9X's had autos with paddles.

[Robert Burns]

I was always put of my the smg box in the e46. Due to a knee problem its hard for me to drive a manual.

I then got the chance of a e92 at knockhill with DCT. My god it was amazing.

Ended up getting myself one the following day and loving it so far.

The only thing I don't like is the yellow angel eyes with the xenons which is a easy fix and also the exhaust note so ended up have the exhaust mod done. Fantastic sound now so much better and worth it.

[cringle]

Once again, DCT it is then! I've heard ppl have booked test drives in the M4, despite me being no.1 on the unofficial list for the M4 at the dealer, nobodys bloody contacted me. A stern phone call beckons methinks

[Wills2]

cringle said:

Hi guys, I previously owned an E46 M3 SMG, and have put my name down for the forthcoming M4. I think I'll go for the DCT option, its going to be the same 7 speed dual clutch gearbox in the E9X carried over. I've never driven the E9X DCT, just wanted to ask about its characteristics...ie does it give complete control and hold the gear like the smg without automatically changing up? Or does it act like VAG DSG gearboxes and do what it likes?

I've had SMG in my e46 and now DCT in the e92 a few points:

1. DCT will thump in S5 or S6 it's great and gives you a bit of old skool fun.
2. DCT will not change up for you in manual mode although it will change down to stop you labouring the engine.
3. In manual mode, if you push the pedal flat to the floor and flick the - paddle once the gearbox will drop into the lowest available gear (so it will go from 7th to 2nd with one touch)
4. Launch control is just as bad as your SMG (giving neither a launch or control)
5. In auto mode the gearbox lacks the PDK race gearshift strategy, it trys to adapt to you but never quite makes it happen.
6. Throttle blips on change down are cool and allow for mid corner down shifts but watch mid corner up shifts in S5/S6 due to the thump if you've got your foot down (not good practise anyway)
7. The box can be a pain when doing 3 point turns as it is slow to engage 1st and reverse (and vice versa) and leaves you pressing thin air if you don't pause between shifts, and once you've pressed the throttle before the gear in engaged it won't engage so you'll just role back (despite it having hill hold) minor issue though.

As for the f82/80 having the same gearbox the software will be different and updated so things might/will be different.