The Porsche Taycan's Two-Speed Gearbox • Hacker News Board

Re: The Porsche Taycan's Two-Speed Gearbox

#181

Post by Dylan16807 » Sat, Sep 07, 2019, 8:12 AM UTC

GhostVII wrote: post #162

Dylan16807 wrote: post #156

Earlier quoted context omitted.

> Are saying that Porsche--which is spending billions of dollars on the Taycan and its transmission--is doing this for no good reason? Yes, they are. They are saying that "better on a track" is a bad reason, and "it makes more money" is a bad reason. That is not a claim that Porsche is incorrectly engineering to reach their goal, or doing anything unprofitable. It's an opinion.

In what way is "better on track" a bad reason? Lots of cars have features which are only really useful on a track, are all of these cars needlessly complex?

A lot of people would say yes, and I would not call them objectively wrong to have that opinion.

Re: The Porsche Taycan's Two-Speed Gearbox

#182

Post by coribuci » Sat, Sep 07, 2019, 8:53 AM UTC

eigenloss wrote: post #159

solotronics wrote: post #150

Earlier quoted context omitted.

Another reason the Taycan can output near maximum power for a much extended time period is it operates at 800v vs 650v as compared to the Tesla.

Higher voltage alone does not magically give you longer sustained maximum power.

Higher voltage means less current for the same power. Since the power dissipated on the battery is proportional with the current you want to draw less current. What a lot of people do not understand is that the lack of a gearbox in an electric car is a big problem. When the motor is running suboptimally the excess energy taken from the battery will be transformed in heat.

Re: The Porsche Taycan's Two-Speed Gearbox

#183

Post by [deleted] » Sat, Sep 07, 2019, 9:22 AM UTC

ztjio wrote: post #178

adrianN wrote: post #164

Earlier quoted context omitted.

It's also unclear to me why a gearbox alone would give you longer sustained maximum power.

Alone it's probably not enough. In combination with other design decisions, it could be the key though. Take for example the smaller battery. Normally that would be a big limiting factor as battery size is somewhat indicative of maximum power output. But by shifting gears once through the acceleration curve, they can compensate for the lower max power. Furthermore, they could keep higher speeds with less constant pow…

[deleted]

Re: The Porsche Taycan's Two-Speed Gearbox

#184

Post by fgonzag » Sat, Sep 07, 2019, 9:30 AM UTC

rconti wrote: post #16

Mikeb85 wrote: post #14

Earlier quoted context omitted.

Porsches have never really been about straightline speed. Always about overall performance and a sports-car feeling. I'm guessing they optimized things like power, gearing and weight placement to offer good acceleration through a range of speeds with amazing handling and decent range at speed.

True, and the Taycan may well be a better car in many ways. But a discussion of the gearbox has nothing to do with handling or sports car feeling. I'm wondering what we're missing here. 5% efficiency improvement at high speeds isn't anything to write home about today. The transmission is a known quantity -- it's just gears, it won't get more efficient as they develop it. The efficiency of the whole system (battery/dr…

Tesla tried to use a two speed transmission back in its Roadster days. They scraped it due to reliability issues. So even Tesla thinks (or thought) that two speed transmissions had technical advantages.

Re: The Porsche Taycan's Two-Speed Gearbox

#185

Post by fgonzag » Sat, Sep 07, 2019, 9:32 AM UTC

gonehome wrote: post #37

rconti wrote: post #16

Earlier quoted context omitted.

True, and the Taycan may well be a better car in many ways. But a discussion of the gearbox has nothing to do with handling or sports car feeling. I'm wondering what we're missing here. 5% efficiency improvement at high speeds isn't anything to write home about today. The transmission is a known quantity -- it's just gears, it won't get more efficient as they develop it. The efficiency of the whole system (battery/dr…

I think the early versions of the original Tesla roadster had gearboxes with multiple speeds, but Elon eventually got rid of it and settled on just having one for later versions of the roadster (and all subsequent Tesla cars). I think they found it didn't give much of an advantage when it did work and that they generally just didn't work very well.

And anybody who has driven a Porsche knows what an immaculate steering and transmission feels like. I seriously doubt Porsche would release something that was not up to the standard of the regular vehicles.

Re: The Porsche Taycan's Two-Speed Gearbox

#186

Post by fgonzag » Sat, Sep 07, 2019, 9:42 AM UTC

davewritescode wrote: post #127

elonismycopilot wrote: post #30

Earlier quoted context omitted.

Well in terms of looks, charging network, city driving, autopilot, price and drag racing I'll take the Tesla. So far we've just seen a bunch of hand waving about how Taycan is better on the track... looks like there is a Model S being sent to Nurburgring to lay that to rest.

There’s almost no chance Tesla is going to get anywhere near the Taycan. There’s been a few professional drivers who’ve given it a shot and breaking 9 minutes has been a challenge. For context, that’s the same lap time as a Mazda MX-5. There’s almost zero chance Elon is going to find another 1:20 with the existing Model S. Just not going to happen. https://youtu.be/Dphw4km60m4

At the end of the video the dude was barely able to break the 170 kph on straights.... The performance degradation throughout 2/3rds of a lap was atrocious. The driver was pretty decent considering he was hauling around a massive sedan, the guy knew the ring very well.

Re: The Porsche Taycan's Two-Speed Gearbox

#187

Post by rukuu001 » Sat, Sep 07, 2019, 11:06 AM UTC

I'm amazed they spent all that R&D loot and then called it 'Taycan' - I can't decide if it sounds more like 'toucan' or 'trashcan'.

FWIW the Wikipedia article[0] on the car has this to say about the name:

> The name Taycan, roughly translates from Turkish as "lively young horse" in reference to the steed of the Stuttgart coat of arms on the Porsche crest.

[0] https://en.wikipedia.org/wiki/Porsche_Taycan

Re: The Porsche Taycan's Two-Speed Gearbox

#188

Post by fluffything » Sat, Sep 07, 2019, 11:46 AM UTC

userbinator wrote: post #147

Mikeb85 wrote: post #14

Earlier quoted context omitted.

Porsches have never really been about straightline speed. Always about overall performance and a sports-car feeling. I'm guessing they optimized things like power, gearing and weight placement to offer good acceleration through a range of speeds with amazing handling and decent range at speed.

Comparing Porsche and Tesla shows that the perception of performance applies to EVs too: European performance is more about the handling, while American performance is more about straightline acceleration. The reason for this difference becomes obvious if you compare what the roads are typically like between the two regions.

Live in Germany, and I care about handling, breaking power, and acceleration at rarely >50km/h, and often at >100-130km/h. Acceleration at 0-100km/h makes no sense for any meaningful use of a car here.

When I'm driving at >250km/h on the highway and one truck tries to overtake another at 80-90km/h, people driving 130 on the middle lane end up switching to the fast lane, so I have to break down to 100-130 km/h, and re-accelerate back up to >250km/h afterwards. The faster that happens, the less my average speed falls.

In Germany at least, one never lands into the highway merging lane at lestt than 60-70km/h, and the normal thing is to be at 50km/h and slowly move towards 80km/h for merging once you are on the merging lane and merge carefully. By the time you finish merging you are already at 120km/h in the slow lane.

If you are driving curvy roads, you want good handling so that you don't have to break down to less than 50-60km/h most of the time, and then you want good acceleration from 50-60 up to 100 km/h, and good breaking. You can't drive curvy roads here faster than 100km/h anyways.

Nurburgring is a mixture between highway and track-curvy roads (realistic curvy roads in germany are not like that), where a skilled driver with a car with good handling rarely drops below 130km/h in the curves, and is at about 250 km/h on all straight segments except for the very last one. Being able to reach 300km/h in the last segment is nice, but it only makes a dent in the overall lap time and doesn't really help if your car has bad handling. Also, its the last segment of the lap, so if your EV is overheating you'll fail miserably there.

The only situation I can imagine in which 0-60 matters is if you are drag racing, and for that, I have a 9.000 EUR BMW S1000R that beats pretty much every single car. Why would anyone pay >80.000 EUR for a drag racing car escapes my comprehension. Why would anyone care about Nurburgring times escapes my comprehension as well. I was once there with the bike, and I almost shit my pants. There is a huge difference between smoothly cruising at 250 km/h in a Germany highway, and driving at 250km/h on Nurburgring. People driving there are insane.

Re: The Porsche Taycan's Two-Speed Gearbox

#189

Post by giobox » Sat, Sep 07, 2019, 12:27 PM UTC

kenhwang wrote: post #134

adrr wrote: post #42

Earlier quoted context omitted.

Model 3 performance needs ceramic brakes for the ring. Car is too heavy for the Brembos and it is at the limit for brake size.

The Taycan currently only comes with two brake options: carbon surface coated brakes or full carbon ceramic brakes.

Porsche have said in many interviews the coating is for cosmetics rather than performance.

Like most electric cars, when driving “normally” you don’t really ever touch the brakes as the energy regen that kicks in when you step off the accelerator pedal slows the car down so effectively. Porsche were worried the discs would develop unsightly surface corrosion from lack of use for some drivers - the coating keeps them looking good.

Re: The Porsche Taycan's Two-Speed Gearbox

#190

Post by giobox » Sat, Sep 07, 2019, 12:32 PM UTC

eldenbishop wrote: post #112

lutorm wrote: post #110

Earlier quoted context omitted.

What's the turbo doing?

I (lol)ed because "turbo" and "turbo-s" are a naming convention from their conventional cars that is fairly non-sensical on an electric car given that they don't have turbochargers. Eg. Macan Of course, the two non-turbo Macan models above both turbochargers so the moniker really just means "the fastest model" in Porsche speak.

I’m surprised people are getting so pedantic about using the Turbo moniker on an electric car. Sure, historically in cars it has typically referred to a type of forced induction commonly used on combustion engines, but it’s also been generally used to mean “FAST” in virtually every other marketing field for decades. I love cars, regardless of the means by which they generate forward motion, and couldn’t care less Porsche called this one a Turbo - it’s performance characteristics are entirely in keeping with what one expects from a Porsche with the Turbo branding.