!!!!! M-DCT / M-DKG is here !!!!!

[Epacy]

Originally Posted by southlight

"you know there's always some truth in..." A saying I'd like to hear/read every single day


Best regards, south

That's a Swamp special.

[T Bone]

Originally Posted by footie

Sorry to burst your wet dream but the Veyron uses the same technology that when into my Golf, sure it's better/over engineered but then again it has to be, the facts are it's being subjected to 1200hp not 200.

By the way a Veyron gearbox cost in excess of 160K but regardless of this the technology in both is basically the same and the same goes for the M-DCT.

You have to come off your perch with this thing that Audi is all bad because it's not the case, each company do things differently that is all. I am level minded and grown up enough to see each for what they are which is a car, nothing more, nothing less.

You really need to get a grip on reality.

My bubble?? BMW is not the company being bought out by a small Stuttgart company because their products suck and they do wet dream projects like the Phaeton and Veyron.

Look at the BMW's press release, this is the first box that will take high torque and high rpms (read sports car / sedan). This is not the GTI grocery getter DSG. When Audi comes out with DSG2 designed to work with the R8 V10 or the new RS5 / RS4, I might be impressed.

I am level minded but I choose to antgonize you because you made a silly comment about DSG vs. DCT.

[T Bone]

I would like to debate a couple of things:

1 - "Pulling the paddle or tipping the gearshift lever only once therefore makes the transmission shift down either one or several gears, whatever is appropriate. The electronic control unit in command of the M double-clutch transmission automatically changes the gear currently in mesh to give the car optimum acceleration under its current driving conditions and at the speed at which it is travelling."

I am not sure if I am comfortable with the computer choosing the gear for me in downshift mode..... Not comfortable at all. Anyone else? Perhaps they use different algorithms for different shift settings?? Yuck! I prefer to choose my own gears at all times....not because I am faster or better than a computer but because I want to control my car's dynamics.

2 - 7 Speed Gearing

In one of the simulations that I ran. The software doesn't even use 7th gear for acceleration to top speed. In fact, the rear end on the MDCT is extremely tall. 7th gear just looks like a gear for fuel economy.

Did BMW favor economy over acceleration??? This would be very bad.

[GregW / Oregon]

Originally Posted by T Bone

I would like to debate a couple of things:

2 - 7 Speed Gearing

In one of the simulations that I ran. The software doesn't even use 7th gear for acceleration to top speed. In fact, the rear end on the MDCT is extremely tall. 7th gear just looks like a gear for fuel economy.

Did BMW favor economy over acceleration??? This would be very bad.

I don't know--the car is fast enough as is. The fuel economy has been taking a rap and to get at least a highway improvement would be nice. It might save some on the gas guzzler tax, as well.

[T Bone]

Originally Posted by GregW / Oregon

I don't know--the car is fast enough as is. The fuel economy has been taking a rap and to get at least a highway improvement would be nice. It might save some on the gas guzzler tax, as well.

Just imagine a shorter rear end and gears that are spaced out to reach the M3's terminal velocity? This car would be considerably faster.

Guessing at Cartest2000's acceleration agorithms, they would imply you are always going to get more torque to the rear wheels using 6th gear. This means BMW wasted 7th gear for cruising like the Z06 uses 6th gear for fuel economy.

That would blow chunks big time.

[enigma]

Originally Posted by footie

I wish I understood the technology that went into each of these gearboxes so I could understand why each companies choose the behaviour of each and how they pulled it off.

This torque overload you are talking about, does this mean the they have chosen to not match the turning of each shaft so that the shift is felt or is it a case there is a brief delay, the latter would surely make it's acceleration slower though ever so slightly and the other would surely place extra wear and tear.

What do you reckon South?

No it means exactly what I posted before. The extra energy in the cars rotational mass of the engine and flywheels is dumped to the rear tires as a brief torque spike when agressive shifting is selected. In the softer modes it soulds like theiy reduce the throttle and dissapate the energy as continued acceleration.

Question: If you know you don't know, why keep arguing with people that do?

[GregW / Oregon]

Originally Posted by T Bone

Just imagine a shorter rear end and gears that are spaced out to reach the M3's terminal velocity? This car would be considerably faster.

Guessing at Cartest2000's acceleration agorithms, they would imply you are always going to get more torque to the rear wheels using 6th gear. This means BMW wasted 7th gear for cruising like the Z06 uses 6th gear for fuel economy.

That would blow chunks big time.

All a matter of priorities. You are focusing only on acceleration. The M3 has always been a well-rounded car that compromises on some areas to achieve that balance. All I'm saying is that the economy of the E92 is disappointing compared to the performance. It is not "wasting" the gear if it improves that aspect of the all-around car.

[enigma]

Originally Posted by footie

I doubt it's faster because if that was the case then the Bugatti would have offered a similar setting, but one thing is for sure it will add wear and tear to the gearbox inners and when a DSG for a GTi Golf cost I believe £6500 to replace I doubt I would use setting S5-6 too often.

You still making things up?

It doesn't add massive wear and tear. It simply recovers the stored energy in the engine that was spinning at ~8400rpm and will need to slow down to ~600- or so.

The other options are to cut the throtle and retreive the energy to substitute for its acceleration. Or, have a much smaller spike over a longer period of time. Ironically, this 2nd option is the worst for the clutch packs.

[T Bone]

Originally Posted by GregW / Oregon

All a matter of priorities. You are focusing only on acceleration. The M3 has always been a well-rounded car that compromises on some areas to achieve that balance. All I'm saying is that the economy of the E92 is disappointing compared to the performance. It is not "wasting" the gear if it improves that aspect of the all-around car.

I understand your perspective but I disagree with BMW's apparent choice.

If you look at the M5 / M6, they reach terminal velocity at the top of the rpm band in top gear. This means the 7 gears are well spaced.

With the M3 M DCT, the car's performance is very much like a 6MT. Why have a 7 speed? I don't understand why BMW would waste 7th gear for economy.....

In many ways, the M3 is a mixed bag of intolerable tradeoffs for me....the engine is not peaky and loses torque in the upper rpm band and now with the spacing on the gears.....the performance is not significant over a 6MT!!!

I guess, this is a setup for the M3 CSL.

[GregW / Oregon]

Originally Posted by T Bone

I understand your perspective but I disagree with BMW's apparent choice.

I guess, this is a setup for the M3 CSL.

That would make sense for ultimate performance.

[enigma]

Originally Posted by T Bone

2 - 7 Speed Gearing

In one of the simulations that I ran. The software doesn't even use 7th gear for acceleration to top speed. In fact, the rear end on the MDCT is extremely tall. 7th gear just looks like a gear for fuel economy.

Did BMW favor economy over acceleration??? This would be very bad.

I view this as a good thing. The first 6 gears are spaced for performance. Much better than the manual. 7th is setup as an overdrive.

In practice in the 0-160 range the DCT car is much better geared. One thing that anoyed me about my other car is 6th was not usefull at the track or on the street. At the track it did't have enough power to ever need it. On the street the car was buzzing so much that I was going nuts on the drives to and from the track. I would have prefered having the taller 6th from the OD version of the manual in that car.

In practice at most tracks the DCT car is going to use 1-5 and the 6mt car 1-4. So you do get to use an extra gear, just not like you first expect.

[southlight]

Originally Posted by T Bone

I would like to debate a couple of things:

2 - 7 Speed Gearing

In one of the simulations that I ran. The software doesn't even use 7th gear for acceleration to top speed. In fact, the rear end on the MDCT is extremely tall. 7th gear just looks like a gear for fuel economy.

Did BMW favor economy over acceleration??? This would be very bad.

It's not different than 6MT, which reaches the limited topspeed in 5th gear. You also have to think of the possibility that someone's delimiting the car. Maximum speed in 6th gear (DCT) is some 270 kph, so for going 300kph you need the 7th gear. 300 kph are at 7800rpm in 7th gear, so I don't think it could be much shorter...


Best regards, south

[footie]

Originally Posted by T Bone

My bubble?? BMW is not the company being bought out by a small Stuttgart company because their products suck and they do wet dream projects like the Phaeton and Veyron.

Porsche are extremely profitable and could have bought BMW if they weren't a privately owned company. You seem to be threaten by Audi for some reason or another and always seem to bring them up in the conversation, especially to me and I don't know for why. Remember I HAVE an M3 on order and I am changing from Audi to BMW, when are you going to get it that I am soon to be part of the team. South, Bruce, Swamp etc don't have a problem with my owning and S5 so why do you and E90Rice have a problem.

Originally Posted by T Bone

Look at the BMW's press release, this is the first box that will take high torque and high rpms (read sports car / sedan). This is not the GTI grocery getter DSG. When Audi comes out with DSG2 designed to work with the R8 V10 or the new RS5 / RS4, I might be impressed.

I don't see the relevance in this statement just because I am comparing one with the other but in reply to you question about DSG2, the S-Tronic with 7 gears I believe will be shown with either the new S4 or Q5 ( this is what I have found out on other sites) and this gearbox is designed to cope with in excess of 500Nm (maybe even more some say) so you can argue that BMW beat Audi to having a 7sp dual clutch gearbox but always remember that it was Audi who designed and introduce it first, more than several years ago.

Originally Posted by T Bone

I am level minded but I choose to antgonize you because you made a silly comment about DSG vs. DCT.

The two are basically using the same technology, how is that a silly comment. IT'S A FACT.

[T Bone]

Originally Posted by southlight

It's not different than 6MT, which reaches the limited topspeed in 5th gear. You also have to think of the possibility that someone's delimiting the car. Maximum speed in 6th gear (DCT) is some 270 kph, so for going 300kph you need the 7th gear. 300 kph are at 7800rpm in 7th gear, so I don't think it could be much shorter...


Best regards, south

The simulator doesn't have a speed limiter. So it goes until it hits an aerodynamic limit vs. power. It shows a vmax of 177 / 178 mph for both cars with an assume Cd of 0.29. (BMW only provides Cd X A so I just took a swag at the Cd).

Is there another value that I should use for Cd?

Also even before Vmax, the MDCT comes out faster but then the differences to speed / distance level off. The effect would be the the MDCT car coming out 1-2 car lengths at the 1/4 mile and then the distance between the cars remaining the same until Vmax.

Here is a chart that the software generated. #1 is 6MT and #2 is MDCT.

[T Bone]

Originally Posted by footie

Remember I HAVE an M3 on order and I am changing from Audi to BMW, when are you going to get it that I am soon to be part of the team. South, Bruce, Swamp etc don't have a problem with my owning and S5 so why do you and E90Rice have a problem.


The two are basically using the same technology, how is that a silly comment. IT'S A FACT.

I really don't have a problem with people making a poor and wrong decision with going with Audi, it is a mistake that they need to deal with

This whole little mini-war stemmed from you making a comment DSG > DCT because you didn't like the programmability.

[southlight]

Originally Posted by T Bone

The simulator doesn't have a speed limiter. So it goes until it hits an aerodynamic limit vs. power. It shows a vmax of 177 / 178 mph for both cars with an assume Cd of 0.29. (BMW only provides Cd X A so I just took a swag at the Cd).

Is there another value that I should use for Cd?

Also even before Vmax, the MDCT comes out faster but then the differences to speed / distance level off. The effect would be the the MDCT car coming out 1-2 car lengths at the 1/4 mile and then the distance between the cars remaining the same until Vmax.

Sportauto measured Cx and Cx x A for their supertest:
Cx: 0.33 - Cx x A: 0.71

I'm not sure how reliable the top speed Cartest calculated is, but I'd tend to claim that top speed should be higher than 177mph (284 kph), rather 185mph.
What rpm did you calculate for the topspeed in 7th, how much shorter could it be?


Best regards, south

[T Bone]

Originally Posted by southlight

Sportauto measured Cx and Cx x A for their supertest:
Cx: 0.33 - Cx x A: 0.71

I'm not sure how reliable the top speed Cartest calculated is, but I'd tend to claim that top speed should be higher than 177mph (284 kph), rather 185mph.
What rpm did you calculate for the topspeed in 7th, how much shorter could it be?


Best regards, south

Here is the thread with the sim that I ran.... http://www.m3post.com/forums/showthread.php?t=107681

With Sportauto's tested Cd of 0.33, the sim using 0.29 should have yield better results for the sim.

Car Assumptions:


M3 6MT


M3 M DCT

[southlight]

I'm not sure if I read your data correctly, does it say that 6MT reaches 177mph in 5th gear and DCT 178 mph in 6th gear? If so that'd be wrong.


Best regards, south

[GregW / Oregon]

Originally Posted by southlight

I'm not sure if I read your data correctly, does it say that 6MT reaches 177mph in 5th gear and DCT 178 mph in 6th gear? If so that'd be wrong.

Best regards, south

You sure--I always heard top speed on the manual was achieved in 5th because of drag limitation in 6th.

[southlight]

Originally Posted by GregW / Oregon

You sure--I always heard top speed on the manual was achieved in 5th because of drag limitation in 6th.

The limited top speed of 155mph is being reached in 5th gear. The M3 can go faster and needs the 6th gear (7th for DCT) to do so since 5th only reaches till 164mph.


Best regards, south

[GregW / Oregon]

Originally Posted by southlight

The limited top speed of 155mph is being reached in 5th gear. The M3 can go faster and needs the 6th gear (7th for DCT) to do so since 5th only reaches till 164mph.

Best regards, south

Guess that was the E46 I was thinking of. thanks

[footie]

Originally Posted by southlight

Sportauto measured Cx and Cx x A for their supertest:
Cx: 0.33 - Cx x A: 0.71

I'm not sure how reliable the top speed Cartest calculated is, but I'd tend to claim that top speed should be higher than 177mph (284 kph), rather 185mph.
What rpm did you calculate for the topspeed in 7th, how much shorter could it be?


Best regards, south

South I agree with your opinion, the Audi R8 has a worse Drag Co than the M3 yet with the same power it WILL reach 186mph.