World Premiere: 2025 Taycan Turbo GT and Taycan Turbo GT with Weissach Package

[whitex]

Weight is indeed a downward force, but in car engineering the vertical force due to mass is just called weight, if the word “downforce” is used it is referring to massless aerodynamic forces.

Somebody in the business may refer to weight as downforce but if so I’ve never heard of it and don’t know anybody who has ever referred to weight as downforce until you did.

Think whatever you like though.

Ok, let me rephrase my question using this terminology. Is downforce always helpful on a vehicle regardless of the vehicle weight. Would a 300 ton locomotive benefit from any downforce at all?

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[f1eng]

Ok, let me rephrase my question using this terminology. Is downforce always helpful on a vehicle regardless of the vehicle weight. Would a 300 ton locomotive benefit from any downforce at all?

A locomotive is on rails so gets almost none of its lateral grip or stability from the vertical force on its steel tyres so downforce is irrelevant to train dynamics.

 

[whitex]

A locomotive is on rails so gets almost none of its lateral grip or stability from the vertical force on its steel tyres so downforce is irrelevant to train dynamics.

Actually, the wheels are conical so if the locomotive does in fact lift up, it will derail easier on turns. However, let me try another way of asking, is there a weight for a road car or truck at which downforce would be completely irrelevant? 5 ton, 10 ton, 20 ton?

 

[rs38]

Can you think of an example from the past ICE age when you could you get a new, comparable (same number of doors, seats, size), non-Porsche production car for about a 3rd of the price, but matching the performance or a top end Porsche car on the track and drag strip?

yes of course:
Porsche GT2(RS) vs. Corvette Z06 and Nissan GTR.
Man, we had tons of discussions in trackday forums 15-20 years ago. Even the price multiplyer was very much the same as now. And the issue was also close to today: you had to mod both Z06 and GTR a lot to gain constant track performance.

 

[MissionE]

That would definitely be a nice addition, and make the Turbo GT somewhat more exotic relative to rest of the line-up.

Not gonna happen in a sedan/suv world

 

[WasserGKuehlt]

Actually, the wheels are conical so if the locomotive does in fact lift up, it will derail easier on turns. However, let me try another way of asking, is there a weight for a road car or truck at which downforce would be completely irrelevant? 5 ton, 10 ton, 20 ton?

I think another way to state your question would be: at which points (tuple) of {mass, speed, aerodynamic coefficient} does lift become significant? (And we’d need to find a way to quantify “significant”. I’ll settle for “weight on an axle reduced by a couple-to-5 percent.”)

Planes fly, no? And weigh significantly more than 20t. Takeoff speed is not very high, either.

The example of the flying Mercedes given above was really scary, and I’ve been wondering for years how they got it so wrong.

 

[f1eng]

The example of the flying Mercedes given above was really scary, and I’ve been wondering for years how they got it so wrong.

A lot of the sportscar teams were not using a wind tunnel much and few (maybe none) with rotating wheels and moving ground.
The general opinion amongst those who had never evaluated it was that it couldn’t make much difference but it did, a vast one.

I started writing too much detail and deleted it but in summary I did a study between prototype car, same car in conventional tunnel, ¼ scale model in conventional tunnel and the same model in my tunnel with moving ground and rotating wheels. The only good correlation was between actual car and ¼ scale model with rotating wheels. With wheels stopped the flowfield is wrong so the results aren’t correctable by a fudge factor.

I was a member of the FIA commision and technical working group for Formula 1 and the FIA asked me to do the same for sportscars. I was shocked how blasé yet ignorant they were about wind tunnel testing back then.
I upset the Mercedes technical boss when I said that the Mercedes looked to me like it was designed to take off - which it did to me and did in fact. He had no idea.

The level of aero ignorance in sports car racing was surprising.

They may have caught up now, certainly the Toyota aero engineers know what they are doing and more companies use wind tunnels appropriate for vehicles nowadays.

Edit to point out the Porsche 919 has very obviously been thoroughly tested in a moving ground tunnel.

 

[rs38]

anyone has seen a leaked PDF similar to the one at the day of the facelift premiere?

 

[Chris8536]

Sounds like you missed the news on the Macan EV? It's true that Porsche are dragging the Taycan upmarket, but that's to create room for the lower models. A full-spec Macan EV turbo would spank a base Taycan anywhere at any time, and cost less or about the same. That's, IMO, "delivering more" (and not the kind that is "less").

They want 90k for the base Macan... did you entirely miss my point?

 

[WasserGKuehlt]

They want 90k for the base Macan... did you entirely miss my point?

The “base” Macan outspanks a 40k$-dearer Taycan, so not sure who missed what.

 

[Chris8536]

The “base” Macan outspanks a 40k$-dearer Taycan, so not sure who missed what.

I like how the dumbest people here always confidently spout their stupidity and don’t even notice.

 

[whitex]

yes of course:
Porsche GT2(RS) vs. Corvette Z06 and Nissan GTR.
Man, we had tons of discussions in trackday forums 15-20 years ago. Even the price multiplyer was very much the same as now. And the issue was also close to today: you had to mod both Z06 and GTR a lot to gain constant track performance.

You could always mod a Honda Civic to beat a stock 911 in a drag race, but today an unmodded Plaid beats a Turbo S in a drag race and around a track, and near matches a stripped down GT version around a track. I always thought Porsche wanted a larger margin of performance between stock cars to help justify the price margin.

 

[snstevens]

Louvres over tyres reduce the lift of the top wheelarch surface and being careful at the front - the Mercedes that did back-flips at Le Mans wasn't tested properly in a suitable wind tunnel and had a big lifting surface 1m ahead of the front axle and only stayed on the ground because of the ground effect under surface, one big enough disturbance raising the front a bit and takeoff.

In case you haven't searched for "Mercedes that did back-flips at Le Mans", I want to share this article. There is an excellent video in the article that clarifies how the design of the Mercedes caused the car to do back flips. One frame from the video is shown below. The video also does a lot to clarify how lift and down forces are affected by design decisions such as wheel base, pitch, etc.

 

[f1eng]

In case you haven't searched for "Mercedes that did back-flips at Le Mans", I want to share this article. There is an excellent video in the article that clarifies how the design of the Mercedes caused the car to do back flips. One frame from the video is shown below. The video also does a lot to clarify how lift and down forces are affected by design decisions such as wheel base, pitch, etc.

Thanks but I am aware what they told the public and I am also aware of what they didn't know at the time about wind tunnel testing.

 

[f1eng]

The “base” Macan outspanks a 40k$-dearer Taycan, so not sure who missed what.

In what respects?

As a dragster we don't know, but maybe, and in every other respect other than passenger volume it will probably be inferior.

Whether the superiority of the Taycan will be worth the money to a potential customer will vary on their requirements.

Tha Macan doesn't look worth the money for me personally.

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