Raven doesn't add up

[sandpiper]

Faster performance means things break more. Sure, the components may be capable of more, but it has to be able to do it safely. Heck, they may have limited the model 3 a bit just so 1 out of 100 launches don't melt the wiring harness or break a half shaft. That really doesn't mean it was "nerfed"

You can buy after market chips for many cars that increase the performance. Some make significant increases. But those chips also void the warranty if the increased power caused the problem.

Exactly. There's more to it than just the motor. The rest of the components need to be able to carry the additional load without damage. You can make pretty much any car go faster, at the cost of more repairs.

 

[Saghost]

So, after looking around trying to find more info, it seems that the most accurate measurement for comparison is the combined torque the cars can produce. Doesn't fully answer why, but if you look at the torque and the weight of the cars, the 0-60 speeds fall into place. All of these cars are limited by their batteries as there is not enough power to drive both motors to their maximum, which points out how Tesla dynamically manages power in these cars.

Model 3 AWD - 376 lb-ft (4.4 sec)
Model 3 P - 471 ib-ft (3.2 sec)
Model S LR - 487 lb-ft (3.6 sec)
Model S P - 687 lb-ft (2.2 sec)

A short section of JB Straubel's blog post on dual motors, batteries and inverters from 2015 which explains why it is useful that the motor power exceeds the battery power:


With the shaft horsepower coming out of the motors the situation is not always as simple as front + rear. As we have pushed the combined motor horsepower higher and higher, the amount of times where the battery chemical horsepower is lower than the combined motor horsepower has increased.

Also, the all wheel drive system in the dual-motor cars distributes available electrical horsepower to maximize torque (and power) in response to road grip conditions and weight transfer in the vehicle. For instance, during hard acceleration, weight transfers to the rear of the vehicle. The front motor must reduce torque and power in order to prevent the front wheels from spinning. That power is fed to the rear motor where it can be used immediately. The opposite happens when braking, when the front motor can accept more regenerative braking torque and power.

Combined torques is challenging to use, because the different motors have different gear ratios to the wheels, and it's only the torque at the wheels that matters.

Tesla didn't give us convenient real time torque data, but looking at the video I linked above, you'll notice that the peak power delivered to the rear motor is 360 kW, while the peak power delivered to the front motor is 177.5 kW.

That front motor we believe is basically the same as the model 3 rear motors. It's likely that the Performance can accept somewhat more than that 177.5 kW - but there's no way it can handle anything close to the 360 kW of the induction motor that's three times the size and weight, and weight transfer prevents them from making up the difference with a bigger front motor on those cars.

 

[jdw]

Combined torques is challenging to use, because the different motors have different gear ratios to the wheels, and it's only the torque at the wheels that matters.

Tesla didn't give us convenient real time torque data, but looking at the video I linked above, you'll notice that the peak power delivered to the rear motor is 360 kW, while the peak power delivered to the front motor is 177.5 kW.

Agree. It was really tough to find anything that was measured the same way between the two models. There was a lot more on the S, largly because of the whole P85D HP fiasco, but nothing corresponding for the 3. In the end, I just went with the Wikipedia numbers, but I wouldn't go to the bank with any numbers I've found so far.

The blog post I linked to was indicative of the problem - power is dynamically allocated, which makes a real world static measurement of a dual motor car tricky. You can figure out the power the battery can deliver, you can find the rated motor powers, but very little as to which motor gets what when and as a result, dyno or wheel hub measurments that are hard to qualify.

 

[Saghost]

Agree. It was really tough to find anything that was measured the same way between the two models. There was a lot more on the S, largly because of the whole P85D HP fiasco, but nothing corresponding for the 3. In the end, I just went with the Wikipedia numbers, but I wouldn't go to the bank with any numbers I've found so far.

The blog post I linked to was indicative of the problem - power is dynamically allocated, which makes a real world static measurement of a dual motor car tricky. You can figure out the power the battery can deliver, you can find the rated motor powers, but very little as to which motor gets what when and as a result, dyno or wheel hub measurments that are hard to qualify.

The frustrating part is the car knows all that data in real time - I'm pretty certain that actual torque values at each motor are being passed back and forth on the CANBus throughout the drive, but we can't see it.

The only cars that give any sort of a detailed numeric output are the Ludicrous cars, and then only when in Ludicrous plus and fully warmed up - I'd love to have both that Stats page and the L+ battery pack temperature gauge available all the time.

 

[TIppy]

The model s manual provides torque and final drive ratios.

Rear performance motor:
650 Nm * 9.734 = 6327 Nm (4667 lb-ft) at the rear wheels

Front motor
330 Nm * 9.325 = 3077 Nm (2269 lb-ft) at the front wheels

For a total of 9404 Nm (6936 lb-ft).

The wheels are about 27 inches in diameter, thus have a 1.125 ft radius.

6936 lb-ft / 1.125 ft = 6165 lb of thrust from the tires on the road.
The s weighs about 4941 lbs + 150 lbs for driver, so the accleration is 6165 / 5091 = 1.21 gs.

The video shows max acceleration of 11.8 m / s^2 which is about 1.2 gs.

 

[Simon21]

So let's say from 0-60, how much faster is Raven?

 

[Saghost]

So let's say from 0-60, how much faster is Raven?

Compared to like model recent Pre-Raven S/X, Tesla claims 0.1 second on both I believe. An improvement, but a small one.

The big Raven improvements are in ride/handling and efficiency.

 

[Trunk Gap]

Had a P90DL just took delivery of loaded raven performance.

- quieter inside
- smoother ride - sport is like the old suspension, standard is, maybe 30%softer. Not Lexus, but noticeably smoother ride
- noticeably faster than my p90dl
- AP much much better
- Screen is way faster....everything generally displays much faster with zero lag, makes the old screen feel ancient
- minor tweaks (Alcantara in door pocket, full leather dash vs Alcantara and leather, different graphics on the cluster (ludicrous performance mode); seats more cushiony and stronger bolsters, etc.