Relative handling of 85, 85D, P85, P85D

with a couple of comments about torque steer on the 85D after the latest update (probably s/w tunable in future) and leaving outright power aside, what is the user experience of handling between the models?

P85/S85
RWD
no front motor
weight bias to rear


85D/70D
AWD 50:50 split
front/rear motors
weight balanced


P85D
AWD 30:70 split
front/rear motors
weight to rear

sorka said:

The P85D is 50/50, not to the rear.

Click to expand...

221 front; 470 rear.
That's rear biased power in my book.

AWDtsla said:

No there is no bias. That's maximum achievable power. There is no center diff to have said bias. Actual wheel torque depends entirely on software.

Click to expand...

THe 470hp rear motor deliivers much higher torque than the 221hp motor. That is rear biased drive. That will affect how the car handles.

AWDtsla said:

Torque steer is generated from differential drive masses, usually unequal length half shafts. They seem symmetrical all the way around on the Model S, at least from any pictures I can find. Is this not true?

Click to expand...

Yes.
However torque steer is also generated when the tire on one side loses traction before the other, usually due to localised variation in the ashphalt, which is likely the case in the S85D and is easily sorted by Tesla traction control algorithm if they deem it necessary.

- - - Updated - - -

Seem to be struggling to get the question out simply.

Two factors at play with the different models.

1. Weight

• the rear motor only models have a rear weight bias and a lighter front as there is no motor there.
• the P85D has a heavier motor at the back and some weight at the front with the smaller motor.
• the 70/85D have the same motors front and back.

Typically in a car with heavier front axle, the understeer is more difficult to control.
So does the P85 have the sharpest turn in?
Has anyone observed this?
The reality may be that the car is just so heavy due to the battery that the differences are too small to observe.

2. Power
A RWD car is typically very different to a FWD car to drive.
AWD is different again. (Modern ICE espcially Audi are using electronic trickery to modify the performance of the diffs and brakes to send torque all over the place to generate dynamic handling.

The P85 is a RWD car.
The P85D is an AWD car with a more powerful/higher torque motor a the rear
The 70/85D has same power/torque front and rear.
So it should be the case that the P85 is most RWD, then the P85D, then the 70/85D which should feel neutral.

Has anyone observed this, or again is the electronics/weight masking it so much that it cannot be observed.

(fwiw I test drove a P85+ yesterday and is felt nicely rwd, with the traction breaking occasionally on hard aceeleration leading to a nice catch by the t/c.)

AWDtsla said:

Torque steer is generated from differential drive masses...

Click to expand...

No it isn't

AWDtsla said:

...usually unequal length half shafts...

Click to expand...

Comonly the case on transverse engined fwd ICE cars. But mass is not the issue, it is the different angles involved leading to different torque vectors, (and a momentary potential effect of drive shaft twist from unequal length shafts).
Torque steer is generally when the driver perceives the car pulling to left or right under hard acceleration, traction clearly is a major part of this.

The focus of handling really isnt so much about torque steer anyway.

More whether addition of a front motor weight increases or decreases understeer into a corner as the centre of gravity has moved forward, and how willing the car is to push the tail wide when exiting a corner espcially the models with the big rear motor. Yes, the are a gazillion other aspects too but mostly they are the same across the model range so neutralised relatively.

bored now

and interested again, thanks lolachampcar ... Lola (used) to be made in my home town btw, sad to see the factory empty these days.

This is exactly the kind of info I was looking for, having driven a P85+ at the weekend, I was quite concerned about the behaviour of the front end, not unruly but definitely unsettled with a hard prod of the accelerator, very much as you describe, setting the air suspension to low did help a bit. Nowhere near BMW or even MB levels of front end bite and stability to my (limited so far) experience.
That the AWD helps with some electronic trickery no doubt helps control this is good to hear. But you are never going to get away from the fact this is one heavy car, nimble it isn't.

So the question for me now is (power aside)
S85D - same power front an rear, so probably tidy but a bit like a skateboard, or P85D and a lighter wallet, but still a more enjoyable rear biased drive?

Just wish they would release the P85D update to increase the overall performance distance between them, as currently above 30mph the gap seems not so big as the outright 0-60 would suggest.
Only got a week or so to update my order!