Edmunds DCT review

[mashit]

Positive DCT review by Edmunds.

http://www.edmunds.com/insideline/do...hotopanel..1.*

We're on final approach into a tight corner, and our left index finger stretches for the minus paddle behind the 2008 BMW M3 Convertible's small, fat-rimmed steering wheel. All we want is a quick, rev-matched, 3-2 downshift from the car's seven-speed dual-clutch transmission.

Our downshift arrives in a violent, noisy spasm, a come-on to every sport biker in the canyon. Yet it still feels like one of the most precise gearchanges we've ever been able to take credit for. It also makes the BMW M3's 4.0-liter V8 very happy. Back down in 2nd gear, the free-revving engine howls to the bikers, and even through gusts of wind and gnats, we hear it tell us how much it hates neutral throttle. If you're not working this V8, you're killing it softly.

But there's nothing messy or emotional about BMW's new dual-clutch gearbox (abbreviated as M DCT, or M DKG if you're German), which is all business in all of its 11 shift modes. It's also such an effective replacement for the 2008 BMW M3's conventional manual transmission that we wonder if it's not a greater threat to M-division purists than a bulky retractable hardtop.

Perhaps "threat" is too strong a word. But unlike the E46 M3's SMG transmission, the dual-clutch transmission in the 2008 BMW M3 Convertible weans you off the third pedal with disturbing ease.

It works like the dual-clutch gearboxes in the Nissan GT-R, Mitsubishi Lancer Evolution MR and Volkswagen R32. But BMW's transmission is as smooth as a real automatic in city traffic, and with five settings for shift speed available in "D," the transition from one gear to another doesn't have to be aggressive unless you want it to be. The M DCT even allows you to creep a bit while parking your M3.

And while the M3's dual-clutch gearbox separates you from the physical involvement that comes with shifting a true manual transmission, it denies you none of the drivetrain performance. Shifts are superhumanly quick and sledgehammer firm in the sequential M5 and M6 modes, and the ergonomically designed shift paddles (upshifts on the right and downshifts on the left) are always in reach if you keep your hands near nine and three on the steering wheel.

The M DCT is even geared like a real manual transmission, with a short-ratio 4.78 1st gear (compared to the 4.055 gear in the six-speed manual) and closely spaced ratios for 2nd through 6th gears. Seventh is a direct 1.00:1 gear — there's no overdrive for this dual-clutch gearbox. At the same time, the DCT car has a taller final-drive ratio than the manual-transmission car (3.154 versus 3.846), so the effective rpm at cruising speed is much the same.

[JEllis]

Great review...thanks for posting it

[skierman64]

Good review...where can I find one of those?

Oh yeah, my garage

[rai]

the DCT won't be available on the coupe or sedan until 2009, and this 2008 BMW M3 Convertible outweighs those cars by an average of 500 pounds. With its complete plate of options, our $81,970 test car also takes M3 pricing to a whole new level. The M5, you'll note, starts at $83,900.

getting expensive.

the DCT won't be available on the coupe or sedan until 2009?

[arr0gant]

Guess the 'vert is OUT for serious enthusiasts....however, not surprised.

[RealSanaii]

Originally Posted by rai

getting expensive.

the DCT won't be available on the coupe or sedan until 2009?

Just love these so-called 'car experts'.

[MADM4]

I love how he says 4.4 liter v8

[Dascamel]

Originally Posted by RealSanaii

Just love these so-called 'car experts'.

+ 1, they need to do more research...

[NYSPEM3]

So are you saying somehow my DCT M3 sedan traveled to my garage... from the future?

Very un-Edmundslike. Their articles are usually factually accurate and well-written.

[arr0gant]

I haven't driven a convertible DCT, but I trust them when they say what they say, comparing the heavy-ass 'vert to the sedan/coupe. We ALL know the rigidity suffers, as well as handling/power/performance from all those Xtra lbs.

[swamp2]

Interesting read. I agree completely with their criticism of the launch control being a bit finicky. Mostly all I have ever done is melt my rear tires.

Also quite interesting to note the widespread and dramatic performance hit the convertible takes. It gets hit everywhere, acceleration, braking, skidpad, slalom, etc. The .95g to .86g skidpad hit is huge. Mostly the weight is the enemy here but the less stiff chassis is contributing as well.

[arr0gant]

I think the metal roof adds a couple hundred more lbs than a cloth roof would. These 200/250 more pounds just KILL what the M3 is supposed to do so well. This is why you'll NEVER EVER see Porsche make metal roofs.

[e46e92love]

Originally Posted by skierman64

Good review...where can I find one of those?

Oh yeah, my garage

Dick

[e46e92love]

Originally Posted by swamp2

Interesting read. I agree completely with their criticism of the launch control being a bit finicky. Mostly all I have ever done is melt my rear tires.

Also quite interesting to note the widespread and dramatic performance hit the convertible takes. It gets hit everywhere, acceleration, braking, skidpad, slalom, etc. The .95g to .86g skidpad hit is huge. Mostly the weight is the enemy here but the less stiff chassis is contributing as well.

Proving once again why you would buy a M//, any M// in convertible form is beyond me....something I will never understand.

[rai]

got the be the heaviest M-car of all time (?) previous gen LS430 were 4100 lbs.

I'm sure it's fine but as they say spending $80K you want something better than fine you want something magical like the M3 coupe/sedan.

I don't want to start a flame war (first words spoken at the start of a flame war I know) but holy mother of god 4140 lbs for an M3?

[valeram]

Did I miss something? I must have slept for almost a year and it is already 2009. That means that I got 1 less year to pay off my M3 DCT.

[nusevad]

Nice review, but wow, their demo car is expensive!!

[Wads]

Originally Posted by arr0gant

I think the metal roof adds a couple hundred more lbs than a cloth roof would. These 200/250 more pounds just KILL what the M3 is supposed to do so well. This is why you'll NEVER EVER see Porsche make metal roofs.

The CLK63 and RS4 Cabs are both cloth tops and both weight as much or more than the M3 vert.

[AZ-BMW]

Originally Posted by e46e92love

Proving once again why you would buy a M//, any M// in convertible form is beyond me....something I will never understand.

Hardtop in the trunk in 22 seconds, back up again in 23 seconds
Those of us who live in sunny, warm weather states really enjoy our verts

[Hans Delbruck]

LOL, it takes the author 2 paragraphs to explain how to use launch control.... then at the end of the article she has the nerve to say "eradicate those evil three-pedal cars altogether"

Does anyone else see the irony in this?

And, getting the facts wrong just shows it was written by someone who is NOT an enthusiast.

I applied for a writing gig at Edmunds once....

[Jack28]

Yeah for sure a Great Review!

Thanks for the Post!

-Jack

[Voltigeur]

Originally Posted by mashit

Positive DCT review by Edmunds.
Yet it still feels like one of the most precise gearchanges we've ever been able to take credit for .

Nice review: thanks for posting it.

Minor quibble: the Bimmer engineers, I am certain, don't believe that any design "credit" is due to the Edmunds' editors No aspersions on mashit mind - bad grammar on Edmunds' part!