accelerating hard and shift shock, is it unavoidable?

[DivideBYZero]

MJinZ = Casiotech spliced with fleabag

Great combo.

 

[EightySix Four]

MJinZ = Casiotech spliced with fleabag

Great combo.

I hate to say it, but stop calling him out without contributing to the thread. Yes he shows a certain lack of knowledge, but if you have nothing to add let it go so we don't derail a thread again.

 

[jlee]

I thought people called all Automatics slush boxes?

People also call BMW cars Beemers. Doesn't mean it's right.

 

[KIAman]

The shock is even worse if your upshit from redline is at or very near your engines peak torque output.

Even my slushbox (ZF 6HP19) produces a nice whack when upshifting full throttle in sport mode, where normal mode is smooth as butter.

 

[DivideBYZero]

I hate to say it, but stop calling him out without contributing to the thread. Yes he shows a certain lack of knowledge, but if you have nothing to add let it go so we don't derail a thread again.

There is pretty much nothing you can do to prevent that slamming feeling when shifting hard apart from shifting a little less hard. BMW fit clutch delay valves so that even if you drop the clutch like a bad habit it won't be as harsh as it would be without it. Not ideal though.

 

[ayabe]

Nope, I've only experienced M- Double clutches.

No you haven't because in any of the higher sport modes, the shift are very quick and very brutal.

 

[BlahBlahYouToo]

I thought people called all Automatics slush boxes?

you obviously have no knowledge of cars.
please get your learn on elsewhere and stop trolling the thread. this thread is not about automatics.

 

[EightySix Four]

There is pretty much nothing you can do to prevent that slamming feeling when shifting hard apart from shifting a little less hard. BMW fit clutch delay valves so that even if you drop the clutch like a bad habit it won't be as harsh as it would be without it. Not ideal though.

Yeah, I kinda like that feeling though

 

[BlahBlahYouToo]

No, you need to let the RPMs drop down to match the speed you're going for the next gear, though this is less efficient than power shifting through.

rev hang on hondas make this really difficult when driving hard.
drove a genesis coupe and it was pretty bad too, but they're known to have rev hang issues as well.

 

[EightySix Four]

rev hang on hondas make this really difficult when driving hard.
drove a genesis coupe and it was pretty bad too, but they're known to have rev hang issues as well.

Heavy flywheel or programmed to do so?

 

[RedRooster]

CVT is such a superior technology! Nissan has it all going on up in that business.

 

[BlahBlahYouToo]

Heavy flywheel or programmed to do so?

stock.
i believe it's for emission reasons.

 

[EightySix Four]

stock.
i believe it's for emission reasons.

I mean is the flywheel from the manufacturer the reason it hangs, or is it programmed into the PCM to do so?

 

[BlahBlahYouToo]

I mean is the flywheel from the manufacturer the reason it hangs, or is it programmed into the PCM to do so?

that's what i mean. it's stock so it's programmed into the ECU. everything is electronic throttle these days.

 

[EightySix Four]

that's what i mean. it's stock so it's programmed into the ECU. everything is electronic throttle these days.

... Yes, but if it has a heavy flywheel then you can't "fix" it from software, you have to physically replace the flywheel.

 

[alpineranger]

Doh.

The conventional torque-converter auto in your Camry has nothing to do with DCT/SMG, which are computer-controlled manual gearboxes with clutches (dual in the case of the DCT, obviously).

There is no slushbox M3, ditto the M5. The C63 does use something of a slushbox, but typical of Mercedes, it's engineered exceptionally well.

Just remember : slushbox =! DCT/SMG

EDIT : I was incorrect, the new Mercedes 7-speed autos are in fact DCTs from Getrag, they've done away with the slushbox (they were the lone holdouts when BMW and Audi went to SMG/DCT style autos for the high end).

Which mercedes 7 speed is this? The little I've read seems to indicate it's a traditional auto with a torque converter and not a dry clutch. Wikipedia agrees with me, although it could be wrong.
http://en.wikipedia.org/wiki/7G-Tronic

As far as I know the BMW gearboxes have torque converters too, except for the SMGs.
http://en.wikipedia.org/wiki/ZF_6HP26_transmission

 

[EightySix Four]

Which mercedes 7 speed is this? The little I've read seems to indicate it's a traditional auto with a torque converter and not a dry clutch. Wikipedia agrees with me, although it could be wrong.
http://en.wikipedia.org/wiki/7G-Tronic

As far as I know the BMW gearboxes have torque converters too, except for the SMGs.
http://en.wikipedia.org/wiki/ZF_6HP26_transmission

http://www.emercedesbenz.com/Nov08/..._Popular_Science_Best_Of_Whats_New_Award.html

Wet clutch, no torque converter.

 

[Viperoni]

... Yes, but if it has a heavy flywheel then you can't "fix" it from software, you have to physically replace the flywheel.

The computers tuning simulates an Idle Air Control valve.

 

[EightySix Four]

The computers tuning simulates an Idle Air Control valve.

I was asking because in the case like my car, where the PCM controls almost everything, it is still almost impossible to get rid of this lag because my flywheel weighs 55(!)lbs.

 

[punjabiplaya]

you can get a lighter flywheel for improved response, but then you can also stall it easier. Flywheels are supposed to be heavy.

 

[amdhunter]

you can get a lighter flywheel for improved response, but then you can also stall it easier. Flywheels are supposed to be heavy.

I was thinking about a lighter flywheel for my 8 so it can rev faster, but I also read somewhere that lighter flywheels can decrease torque at lower RPMs? Is that true? This car is pretty torqueless as is already.

 

[TraumaRN]

Any shifting in any car feels strange and rough to me especially since my car has an e-CVT/single planetary gearset...but I guess my car does away with shift stock so yes it's avoidable

 

[Arkaign]

Which mercedes 7 speed is this? The little I've read seems to indicate it's a traditional auto with a torque converter and not a dry clutch. Wikipedia agrees with me, although it could be wrong.
http://en.wikipedia.org/wiki/7G-Tronic

As far as I know the BMW gearboxes have torque converters too, except for the SMGs.
http://en.wikipedia.org/wiki/ZF_6HP26_transmission

Yep, the newest Merc C63 has the dual-clutch MCT7, dropping the torque converter slushbox design. Most Mercedes don't use the MCT7 though.

The BMW autos are still slushboxes, but the M cars have SMGs instead.

As the DCT/SMG design is a rougher, more performance-oriented solution, it doesn't have a place in replacing the conventional auto slushbox design in most passenger cars, particularly in pure luxury models that depend on smoothness/quietness as far more important than shifting in .00x MS.

 

[BlahBlahYouToo]

... Yes, but if it has a heavy flywheel then you can't "fix" it from software, you have to physically replace the flywheel.

how many manufacturers do you know that don't optimize clutch/flywheel operation for ease of use?
esp. pedestrian makes like honda and hyundai.

i thought it'd be pretty obvious.

 

[overst33r]

To avoid the drivetrain shock it causes, I just shift slow and wait for the revs to come down for the next gear. Unless you have a 2lb flywheel, you can't shift fast/smoothly at the same time.

I cringe on a hard 1-2 shift on most cars. A bit less when the wheels brake loose which alleviates some of the shock.