Next gen Roadster

[AnOutsider]

What exactly is the GEN 3 platform, does anyone know? Seems like it's just a smaller wheelbase and battery pack? Not a car engineer, so not sure what else would be different. If they're keeping with the skateboard thing, then just build a smaller skateboard. I suppose they could be ditching it for Gen 3 if it makes manufacturing cheaper tho?

 

[Grendal]

Tesla has announced a GEN III crossover, will that push back the Roadster 2.0 even further? My guess would be yes. What do you think?

 

[dsm363]

I think they'll need a halo car again at some point and I'm hoping it's around 2015-2016 after Model X launch. It would be such a small volume and if based on the Gen III platform, could serve as a test bed for that prior to rollout. I wonder if they'll go further into supercar territory than the Roadster already is ($150k with sub 3 second 0-60 times) or go more for a Porsche fighter and around $100k in a 2+2 seater.

 

[Grendal]

I think they'll need a halo car again at some point. I wonder if they'll go further into supercar territory than the Roadster already is ($150k with sub 3 second 0-60 times) or go more for a Porsche fighter and around $100k in a 2+2 seater.

My guess would be the latter. With the skateboard design you gain a lot of space. Tesla will have learned how to do the four wheel drive right with the Model X. My guess would be sub 3 second, 2+2 seater, and four wheel drive for the performance version. Interestingly, I don't see them focusing on range with the new Roadster. There will plenty of Teslas that can go the distance and it won't be as necessary to drive a sporty roadster for long commutes. I'd say the starting pack for the new Roadster is 150 miles. Why not?

 

[AnOutsider]

No way. 200 min, likely 250 to match the old roadster. It's an expensive car, so a lot of battery cost can be absorbed into that.

 

[frequencydip]

Any new roadster has to have better range than the old roadster or no one will buy it... People expect upgrades not steps backwards... 300 mile plus min...

 

[richkae]

The Roadster is a great car but it has many deficiencies when compared to other sports cars that are actually used as sports cars.
That means sport driving them on a race track or autocross - things people who really love sports cars want to do.

The air cooled motor gets hot and limits your power. Solved with a water cooled motor.
The big battery box makes for a high CG which hurts the handling. Solved with the Model S battery under the floor design.
The little tires and tiny brakes hurt real performance. Solved by designing the car from the ground up and not starting with an Elise and adding 800 pounds.
The limited battery makes it difficult to use as a track car. Solvable with supercharging or battery swapping.
No control over regen and power characteristics limit tuning and driving styles. Easy software-only fixes.
Acceleration drops off quickly at the high end because of the single gear and low top speed. Not sure how they solve this.
It's a black box and people want to tinker. Again, no idea.

Fixing most of those things makes the next Roadster a dramatically better sports car. I want those things before worrying about improving the 0-60.

 

[TEG]

Nice summary, Richkae...

 

[7racer]

I use to race my RX-7 more and only occasionally now the GT-R.

I would say for an all electric sports car....I would rather see Tesla "do it differently".

I don't care as much about little tires. You just want tires that can fit cheap sticky rubber. Some of the fastest cars on the track have small wheels. Also most real racers swap out large wheels for smaller ones to save weight. 17's weigh less than the 20" on my GT-R. Also, I love regen. Brake fade is a big problem in auto racing. Many times you spend time ducting air or even the new "in" thing of spraying water to cool the brakes. If the regen could take that away that would be a huge advantage on a twisty course. Also, I think the brakes could be easily made better with a bigger brake and ceramic (to keep weight down).

About top speed...couldn't gearing fix that?

 

[TEG]

...About top speed...couldn't gearing fix that?

Electric motors are great at providing gobs of low end torque for good off the line acceleration.
I think top speed can be limited by the power output capability of the battery pack.
Electric cars tend to be extremely efficient (compared to ICE vehicles) at low speeds, so get decent range around town even with a (relatively) small amount of on-board stored energy.
As wind resistance (at high speed) starts to become a more dominant factor, the limit energy stored on-board starts to become more noticeable.
(In other words, and EV traveling at 150MPH is likely to run out of juice rather quickly.)
Basically, if you start adding gears in an effort to get higher top speed I think you will run into other limitations.

 

[richkae]

I use to race my RX-7 more and only occasionally now the GT-R.

I would say for an all electric sports car....I would rather see Tesla "do it differently".

I don't care as much about little tires. You just want tires that can fit cheap sticky rubber. Some of the fastest cars on the track have small wheels. Also most real racers swap out large wheels for smaller ones to save weight. 17's weigh less than the 20" on my GT-R. Also, I love regen. Brake fade is a big problem in auto racing. Many times you spend time ducting air or even the new "in" thing of spraying water to cool the brakes. If the regen could take that away that would be a huge advantage on a twisty course. Also, I think the brakes could be easily made better with a bigger brake and ceramic (to keep weight down).

About top speed...couldn't gearing fix that?

I am not talking about tire diameter, I am talking about width. The roadster has 175s in the front ( 195s on the sport ) and 225s in the back.
It's just not enough rubber.
I totally agree about picking a diameter that allows for race rubber and lightness - not looks.

I don't want to turn off or reduce the regen always, just sometimes. Motor heat may still trump brake fade sometimes, and then you want regen off.
Yes it's an easy fix to make the brakes bigger.

 

[richkae]

Electric motors are great at providing gobs of low end torque for good off the line acceleration.
I think top speed can be limited by the power output capability of the battery pack.
Electric cars tend to be extremely efficient (compared to ICE vehicles) at low speeds, so get decent range around town even with a (relatively) small amount of on-board stored energy.
As wind resistance (at high speed) starts to become a more dominant factor, the limit energy stored on-board starts to become more noticeable.
(In other words, and EV traveling at 150MPH is likely to run out of juice rather quickly.)
Basically, if you start adding gears in an effort to get higher top speed I think you will run into other limitations.

If you look at the horsepower required to go a certain speed from the efficiency spreadsheet, it is clear that the Roadster could go faster.
Range will be a problem, but if you are trying to lap the racetrack with your friends in the ICE cars, they are going to blow past you on the straightaway every time. 200 mph is not necessary, but at the local car club track days, people will hit 150mph on the straights.

At a track day, you quite often only get 15-20 minutes to drive and then wait for an equal or longer amount of time. Plugging in at 20kW lets you extend your playtime, plugging in at 90kW would let you extend your playtime a lot.
Battery swapping would let those with ridiculously deep pockets road race in a manner very similar to ICE cars.

 

[TEG]

If you look at the horsepower required to go a certain speed from the efficiency spreadsheet, it is clear that the Roadster could go faster...

I think there is a difference between peak horsepower and sustainable horsepower. Top speed requires constant output. The Roadster may be able to generate high horsepower for a limited time to do blasts of acceleration, but could start to overheat things if you try to keep it at max HP too long. The battery cells probably don't like having high output for too long either.

 

[daniel]

I like my Roadster. I DON'T want gears. That's just something else to go wrong. But then, I don't race and might never take it on a track. I like the acceleration and handling, but don't need it to be a race car.

The things that need fixing are minor:

--> The seats are very uncomfortable. They could be improved (softer).
--> Needs a way to recover change and other small items that fall out of my pockets and wind up under the seat.
--> Needs a few places to put stuff. Anything put in that little cubbyhole to the left of the steering wheel falls out every time I accelerate. Needs a change cup.
--> The Alpine unit is lousy. But I'm sure they'll never go back to that. Plenty of negative feedback already.

I don't need 245 miles of range, but I like it because it's a buffer against eventual aging of the pack. And the fact that other Teslas will have long range does not mean that Roadster doesn't need range. Plenty of people will own one EV. If I owned an S and the Roadster I'd take the S on longer trips, but I don't. 245 miles is ideal. Plenty for an enjoyable afternoon in the country.

They tried a two-speed transmission and it kept breaking. Stick with one speed! But I like the idea of all-wheel drive.

I gather that the Taylor mesh top would not exist were it not for the Lotus. The Roadster Mk II won't have that advantage. They should offer a mesh top. I cannot deal with top off on the freeway. Too much wind. With the mesh top it's perfect, but were it not for that, I'd need to have the top on at freeway speeds.

 

[richkae]

I think there is a difference between peak horsepower and sustainable horsepower. Top speed requires constant output. The Roadster may be able to generate high horsepower for a limited time to do blasts of acceleration, but could start to overheat things if you try to keep it at max HP too long. The battery cells probably don't like having high output for too long either.

Agreed. They will need to improve the sustainable power as well. The current Roadster wasn't designed with the racetrack in mind.

I am trying to enumerate the things that need to improve so that when you show up at a club day at the local racetrack with your Gen III Roadster, that everybody there says "I have to get me one of those".

The current Tesla Roadster accelerates great, corners ok, brakes below average and gets toasted on the straights - and it only does it for 3 laps because the motor gets hot.
If the Gen III Roadster turns the fastest laps for 20 minutes ( which it could easily do by winning acceleration, and being close or equal in the other aspects ) a lot of sports car guys will want one - even if it will need to spend time plugged in to a supercharger after every session.
If you dominate when you are on the track, downtime is forgiven.

 

[vfx]

At the 2012 Stockholders meeting Elon started to call the Gen III the "Model..." and then changed to Gen3. Not sure if the car will be another Model, ("T") or if he was simply correcting staring to say Model S or X.

Just name it already!

 

[TEG]

I think with a transmission they could actually improve the off the line performance a bit even if they don't try to raise the top speed.
The Roadster doesn't seem to accelerate as well in the 0-10MPH range as it does in the 10-60MPH range.
Even the gobs of low end motor torque are muted off the line due to the tall gearing.
But I am NOT voting for them to do a transmission. It is great that it is so simple and direct without the added complexity and expense of a variable ratio.

I bet next gen Roadster could have higher peak 'C-rate' cells, higher motor RPM, and better cooling all which could lead to a slight increase in top speed.

 

[AnOutsider]

At the 2012 Stockholders meeting Elon started to call the Gen III the "Model..." and then changed to Gen3. Not sure if the car will be another Model, ("T") or if he was simply correcting staring to say Model S or X.

Just name it already!

I caught that too, but I think he was talking about the sedan in any case (would make sense to keep with the "Model" nomenclature). Many have spoken up on here that a new roadster as described (2+2, possibly not convertible) wouldn't be a TRUE Roadster, so I could see them leaving the Roadster name in the past and calling it Model R or something. It's also possible there will be a Gen III coupe with a performance package that could be the Model R and Tesla will keep the "Roadster" for halo cars going forward.

 

[frequencydip]

The next gen roadster doesn't need a transmission just 4 wheel drive with different gearing on each axel, rear axel is a low gear for high torque off the line 0-60 and front axel is geared towards a tall gear for 60mph to 150+

 

[AnOutsider]

The next gen roadster doesn't need a transmission just 4 wheel drive with different gearing on each axel, rear axel is a low gear for high torque off the line 0-60 and front axel is geared towards a tall gear for 60mph to 150+

I thought someone else here mentioned that as well. Is that what they're doing on the X?