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The Porsche Taycan's Two-Speed Gearbox

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Re: The Porsche Taycan's Two-Speed Gearbox

#171

Post by simonsquiff »

jm1234567890 wrote: post #169
reitzensteinm wrote: post #168

Earlier quoted context omitted.

Which makes Elon's promise of sending the Model S round the ring a bit confusing. Presumably it would be a suicide run to match the Taycan, which to my understanding would involve modifications and not be eligible for the same category. Either it was an idle boast, or we're about to see the launch of the 21700 Model S.

The new raven model S has the same battery chemistry as model 3

It does not. Raven altered the motor and suspension, battery is same as it ever was for MS (18650) M3 uses 27100, which is taller so can’t just be dropped into the current MS

Re: The Porsche Taycan's Two-Speed Gearbox

#172

Post by paganel »

phkahler wrote: post #89

Aside from not providing much of any performance benefit, this will introduce difficulty coordinating regenerative braking through the shift point. One of my former employers had a group trying really hard to make a 2-speed for EVs make sense. It just doesn't. If there is an efficiency gain, it's probably better to throw the extra money and weight into the motor. An exception might be if you want to cruise at 120+ mp…

Cruising at 120+ mph on long distances happens a lot on German autobahns, one of Porsche’s main markets.

Re: The Porsche Taycan's Two-Speed Gearbox

#173

Post by CamperBob2 »

dragontamer wrote: post #80
Zanni wrote: post #70

Earlier quoted context omitted.

Serious question: how is this antisocial behavior? I understand wanting to stick with the flow of traffic when you're part of the pack, but if you're in front of the pack, what's the advantage (to anyone) of hanging back?

1. By accelerating dramatically off the line, you're telling the other cars that they are driving too slowly. 2. Alternatively: you may be sending a signal that you want to drag-race with someone. And nobody likes it when drag-racers start playing on public roads. Keep that stuff off the streets and on the track only. Now sure, if the cars next to me are driving slowly, I'll leave them in the dust. But its not someth…

1. By accelerating dramatically off the line, you're telling the other cars that they are driving too slowly.

Which they often are. No fuel or pollution is saved when you creep away from a light so slowly that it keeps several cars behind you from making it through until the next cycle.

Re: The Porsche Taycan's Two-Speed Gearbox

#174

Post by elihu »

adrianN wrote: post #164
eigenloss wrote: post #159

Earlier quoted context omitted.

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

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

Most electric motors are most efficient and can generate the most power within a certain RPM range. (It's a lot wider than gas engines, but beyond a certain speed the torque falls off.) If you can drive at high speeds at a more efficient motor RPM, then that's less excess heat for the motor and inverter to deal with, and less current draw from the batteries.

Re: The Porsche Taycan's Two-Speed Gearbox

#175

Post by URSpider94 »

adrianN wrote: post #164
eigenloss wrote: post #159

Earlier quoted context omitted.

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

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

For single-speed EV’s, the motors are operating very far away from their maximum efficiency point at high speeds. By upshifting, you can reduce the number of revs required at top speed, which should improve efficiency and reduce heating of the motors.

Re: The Porsche Taycan's Two-Speed Gearbox

#176

Post by ztjio »

zaroth wrote: post #160
ztjio wrote: post #136

Earlier quoted context omitted.

So, I'll just hop in here and lay out the spoiler. There is a major performance difference in the Taycan, it's endurance, and it's highly likely this transmission is a key element to achieving it. For those that don't know, Tesla's cars can not keep their maximum performance up for a very long time. The battery gets hot and lowers power output until it cools back down. The Taycan, while not having as impressive max s…

This is more of a function of battery chemistry on the S/X - the Model 3 does not have the same power restriction under load.

You're super 100% wrong. The model 3 absolutely does have the same restriction under load. I have no idea where you're getting your ideas.

I am a Model 3 owner, I assure you it will reduce power after a time. No need to take my word for it though you can find plenty of autobahn demo videos showing it. It's not terrible but it is a thing and it's "worse" with track mode.

Numerous "sporty" car reviews also mention this fact. It's just the way it is. Not an impact to most drivers. Absolutely critical to someone who loves the track.

Re: The Porsche Taycan's Two-Speed Gearbox

#177

Post by ztjio »

reitzensteinm wrote: post #168
zaroth wrote: post #160

Earlier quoted context omitted.

This is more of a function of battery chemistry on the S/X - the Model 3 does not have the same power restriction under load.

Which makes Elon's promise of sending the Model S round the ring a bit confusing. Presumably it would be a suicide run to match the Taycan, which to my understanding would involve modifications and not be eligible for the same category. Either it was an idle boast, or we're about to see the launch of the 21700 Model S.

Once around the ring is not an issue. It's a day at the track that's a problem, not one lap. And not an issue at all if you're fine with waiting periodically while the battery temp comes back to optimal.

Re: The Porsche Taycan's Two-Speed Gearbox

#178

Post by ztjio »

adrianN wrote: post #164
eigenloss wrote: post #159

Earlier quoted context omitted.

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

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 power output.

The reason this matters is because a smaller battery will produce less heat overall, which will be easier to cool, and so on.

Anyway it's just a theory. The facts remain: the Taycan can do something the Teslas can't and this gearbox is the biggest single meaningful difference in design of the powertrain. It stands to reason they are related facts to some degree or another.

Re: The Porsche Taycan's Two-Speed Gearbox

#179

Post by lazyjones »

_ea1k wrote: post #55
gleglegle wrote: post #5

It's a little surprising that even with a two-speed Gearbox the Taycan has neither better range nor low range 0-60 acceleration than the Tesla P100D (which has the same size battery). Obviously spec comparisons aren't the whole story and the handling and high-range acceleration may be better on the Taycan. Looking forward to seeing more comparisons and already glad to see more EV models in this category. Edited incor…

I think this is a benefit only at higher speeds, tbh. The Tesla single speed setup seems to be really tuned towards low end acceleration, which admittedly is a logical thing to tune for in a premium family sedan. We've already seen some pretty good hints that the next Tesla Roadster may have at least a two speed gearbox, probably for similar reasons.

> The Tesla single speed setup seems to be really tuned towards low end acceleration, which admittedly is a logical thing to tune for in a premium family sedan.

It's probably actually tuned for range/consumption. The Taycan gets roughly 2/3 the range of a Model S despite better aerodynamics and almost the same battery size.

We'll see what EV drivers value more, track performance or range.

Re: The Porsche Taycan's Two-Speed Gearbox

#180

Post by lazyjones »

youeseh wrote: post #91
phkahler wrote: post #89

Aside from not providing much of any performance benefit, this will introduce difficulty coordinating regenerative braking through the shift point. One of my former employers had a group trying really hard to make a 2-speed for EVs make sense. It just doesn't. If there is an efficiency gain, it's probably better to throw the extra money and weight into the motor. An exception might be if you want to cruise at 120+ mp…

Which part of cruising at 120+ mph for long distances is not realistic?

I eagerly await to see the Taycan's range at 120+ mph. evcalc.ch suggests it would be around 164 Km for 200 Km/h (Turbo S).
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