"Lag" on acceleration

[fullmetalbaal]

I’m asking Porsche what they’re doing. Because they’re doing such a terrible job. As illustrated by my examples.

You’re confusing the statement for “what are you even doing in a Porsche”, which is not what I said.

Yup. Acknowledged. I clearly can't read. I'm sorry.

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[Jhenson29]

Yup. Acknowledged. I clearly can't read. I'm sorry.

You don’t have to apologize. I was making fun of you, for sure.

Damnit…now the moderators are gonna come…

 

[fullmetalbaal]

You don’t have to apologize. I was making fun of you, for sure.

Damnit…now the moderators are gonna come…

Hey, a bit of humor and good natured ribbing is fun. I can take it - and I like dishing it out as well.

I just don't appreciate it when it turns into "you shouldn't even own XYZ product/do XYZ activity if you don't agree with this". (which you didn't say) The reason being that in my experience that kind of behavior quickly shuts down any kind of dissent/criticism/different voices, and a handful of loud people end up dominating an echo chamber.

 

[Jhenson29]

What I want is 2 modes:
- linear, clean and instant acceleration
- linear, clean, instant and aggressive acceleration.

BMW did that pretty well on their naturally aspirated M3s and M5s.
Porsche NA 911s do this well as well IMHO.

In all seriousness, every automatic I’ve ever driven had a lag and then jerk to some degree when stomping on the accelerator (assuming it’s in automatic).

It’s one of the reasons I want a manual 992 instead of a PDK. I really can’t stand that reactive nature of the transmission. Bleh.

I think the biggest difference on the Taycan is that it’s electric and the motor has different characteristics. (As well as possibly the clutch type.)

People always talk about the low end torque or acceleration…but more than those, I think, it’s the jerk rate. The rate of change of torque on an electric motor is ridiculous.

When I trend motor current at 10-20ms, the change can be instantaneous (when the demands calls for it). I have some multi-drive torque control loops that have to run at 250 microseconds (4000 times a second).

That (the high rate of change of torque) , to me is the characterization of an electric motor that makes it feel different to drive.

So, that is at least some of what is felt. It’s well within Porsche’s control to smooth it out, but I think then we’d have threads about how lazy the car is when you slam the accelerator in normal, even after the gear change.

Can’t make everyone happy.

The other possible factor that I alluded to earlier is the clutch type. It’s possible that the dog clutch for first takes slightly more precision and thus time to engage. I don’t know for sure or have any data, but that’s my thought.

Really though, at the end of the day, to me…it just feels like any other lazy automatic. There might be differences, but it’s reactive just the same.

So, I leave it in sport. And there’s no issue.

FWIW, my wife only drove in normal and doesn’t complain, but I’m also not sure she’s aware the accelerator pedal has more than a quarter inch of travel.

 

[fullmetalbaal]

In all seriousness, every automatic I’ve ever driven had a lag and then jerk to some degree when stomping on the accelerator (assuming it’s in automatic).

It’s one of the reasons I want a manual 992 instead of a PDK. I really can’t stand that reactive nature of the transmission. Bleh.

I think the biggest difference on the Taycan is that it’s electric and the motor has different characteristics. (As well as possibly the clutch type.)

People always talk about the low end torque or acceleration…but more than those, I think, it’s the jerk rate. The rate of change of torque on an electric motor is ridiculous.

When I trend motor current at 10-20ms, the change can be instantaneous (when the demands calls for it). I have some multi-drive torque control loops that have to run at 250 microseconds (4000 times a second).

That (the high rate of change of torque) , to me is the characterization of an electric motor that makes it feel different to drive.

So, that is at least some of what is felt. It’s well within Porsche’s control to smooth it out, but I think then we’d have threads about how lazy the car is when you slam the accelerator in normal, even after the gear change.

Can’t make everyone happy.

The other possible factor that I alluded to earlier is the clutch type. It’s possible that the dog clutch for first takes slightly more precision and thus time to engage. I don’t know for sure or have any data, but that’s my thought.

Really though, at the end of the day, to me…it just feels like any other lazy automatic. There might be differences, but it’s reactive just the same.

So, I leave it in sport. And there’s no issue.

FWIW, my wife only drove in normal and doesn’t complain, but I’m also not sure she’s aware the accelerator pedal has more than a quarter inch of travel.

Agreed on the problem on even PDK, and I too would spec a manual transmission.
And IMHO the turbo engines, for all their fancy tech, still don't have the immediacy of a naturally aspirated car. But even a PDK turbo is WAY WAY smoother than whatever thing they plonked into the taycan.

Whether or not this is actually faster, who knows. But since most of us are not professionally racing these cars, this is really more about perceived performance than actual.

And this kind of lag, especially when one wants to quickly just jet over an intersection that's flipping to yellow/red, is exactly the opposite.

I would leave it in sport, but I don't want the harsh suspension setting (the roads are just not there quality wise around here). AFAIK there's no way to set sport mode transmission but normal suspension and leave it as default - is there?

 

[Jhenson29]

AFAIK there's no way to set sport mode transmission but normal suspension and leave it as default - is there?

I don’t know. I leave suspension in sport plus all of the time. I can check sometime, but someone else will probably chime in before I get to it. It’s not my DD so it could be a few days.

 

[Jhenson29]

Whether or not this is actually faster, who knows. But since most of us are not professionally racing these cars, this is really more about perceived performance than actual.

I think what I was suggesting is that the Taycan has potential reasons for both more lag (clutch type) and more jerk (electric motor) which could both contribute to a more noticeable difference. Highly speculating on the clutch on my part though.

 

[fullmetalbaal]

I think what I was suggesting is that the Taycan has potential reasons for both more lag (clutch type) and more jerk (electric motor) which could both contribute to a more noticeable difference. Highly speculating on the clutch on my part though.

Personally, I have less trouble with the "jerk", and more with the lag.
I am tempted to actually measure it, it feels so pronounced that I bet you can pick that up with an accelerometer.

 

[buruburu]

You do NOT want a clutch based transmission in the Taycan or any EV cars in general. It will be shredded into tiny bits of metal and carbon fiber material on the first shift.

Porsche probably could of done a more instantaneous shift, but man oh man the shock to the entire would probably be massive and terrible for the longevity of the car.

 

[Doc Sportello]

Really useful responses on here - many thanks!

I have to say I thought I was well read on the car before I took my CT4 home but the 'normal' experience surprised me, and it's interesting to read the explanations provided above.

I knew the sport settings were more engaging from the PEC day that allowed me to explore each drive mode, but I didn't appreciate the compromises involved in trying to coax a more spirited driving response out of the car in normal mode. Or maybe I just have a heavy foot?!

And to the question about combining sport throttle with 'comfortable' suspension, I thought I had set this up already under the individual drive mode. Feels fine to me, but I'll have to check.

 

[Archimedes]

This is why the transmission is by far my least favorite "feature" of this car.
Absolutely criminal how janky performance is in normal and range.

Janky? The car is silky smooth in normal. The software assumes that you’re driving ‘normally’ and reacts accordingly. You’ll notice that if you put it in sport, it reacts more ‘sporty’.

 

[fullmetalbaal]

Janky? The car is silky smooth in normal. The software assumes that you’re driving ‘normally’ and reacts accordingly. You’ll notice that if you put it in sport, it reacts more ‘sporty’.

Pretty simple to trigger in normal driving behavior...

Putter around at 20-30 mph, then push down the accelerator ~5-6/10.
This isn't unusual for "normal" driving: making a traffic light, speeding up to match speed for a highway on-ramp, etc.

When the car down-shifts, you will feel it. Whether or not that's an issue or completely irrelevant is of course a matter of taste, but "silky smooth" it is definitely not.

 

[Jhenson29]

You do NOT want a clutch based transmission in the Taycan

The Taycan transmission has two clutches. One for each gear. Plus the lsd.

 

[buruburu]

The Taycan transmission has two clutches. One for each gear. Plus the lsd.

Yes, you are correct, the Taycan uses a dog clutch to change gears.

For clarification, what I meant to impart is that you do not want to have a friction based clutch which is in 99% of consumer manual cars. Given the complexity of the a DCT clutch and how fast a EV motor spins, I would be very surprised a DCT can handle it and not shatter itself into pieces over the life of the vehicle.

 

[Archimedes]

Pretty simple to trigger in normal driving behavior...

Putter around at 20-30 mph, then push down the accelerator ~5-6/10.
This isn't unusual for "normal" driving: making a traffic light, speeding up to match speed for a highway on-ramp, etc.

When the car down-shifts, you will feel it. Whether or not that's an issue or completely irrelevant is of course a matter of taste, but "silky smooth" it is definitely not.

Sorry, but if you do that and go to half throttle i.e., 5-6, it does not downshift. Rather it takes off smoothly and rapidly in second gear. Of course, if you slam the loud pedal or put it to the floor, you're going to get a downshift and tiny delay. Even then it ain't janky, and if you're just smooth with the pedal you can get this car to fly off without downshifting to first. I just did it multiple times on way back from the practice range.

I drive like a nutter in my 4S and find the car to be remarkably quick and smooth, as do all the people that ride with me. They constantly comment on how smooth the car is when accelerating hard. And I drive in normal mode about 80 percent of the time.

Also, you do know there is an Individual mode where you can customize things and always start in first gear, right?

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