Newer P90DL makes 662 hp at the battery!!!

[sorka]

See my previous post, where I've 'suttly' shifted my argument to efficiency.

Ahh

I'll do some digging around to try and find it, but I have some graphs that plot KW from the battery with wheel horsepower using a vbox. They start out being perfectly parallel but as speed increases, they start to diverge. I surmised that that wind resistance was factoring into the horsepower measured at the wheels declining against the power at the battery. However, when I did a cost down from something like 100 MPH, the calculation was off. It was then that I discovered that the formula Racelogic uses to calculate horsepower had a typo in it which everyone here confirmed when I posted it.

After fixing that, the KW curve from the battery matched the wheel hp (minus a fixed drivetrain loss). I haven't measured it directly, but it's clear from other vbo files folks have sent me of their 1/4 mile runs, that motor efficiency is nearly flat to about 100 MPH and then starts dropping like a rock after 110 MPH.

Tesla really picked the right ratio based on their motor efficiency. Shorter gearing would have sacrificed too much efficiency at freeway+ speeds. Taller gearing would have resulted in more torque at the motor for every corresponding wheel RPM requiring bigger motor bearings/journals, motor shaft, and beefier diff.

 

[sorka]

Well at a fixed voltage the power is a function of the current, but I get your point if the power stays the same the current will also.

See my previous post, where I've 'suttly' shifted my argument to efficiency.

Keep in mind that on something like a P85 that isn't normally maxing out it's fuse, it's pretty much puts out about 375 KW at all SOCs down to the mid 30s.

So as the voltage drops, the software pulls more current from the battery to keep the power the same. This is why you won't notice any difference in performance on a P85 until the battery gets quite low vs a PD car where the power is dropping as the SOC drops because it's already pulling maximum current at all SOCs.

The P(85)(90)D(L) cars max out the fuse all the time, so the power simply drops as SOC drops because the voltage drops and the software can't pull more current as the voltage drops to keep the same power.

 

[commasign]

Instead of going back to their previous practices, Tesla is simply adding more wiggle room in their verbiage. Soon, we will be discussing what the meaning of is is when Tesla says the car is XYZ.

Lol. True. I guess my main point is that if the new disclaimer text was intentional (rather than just blanket get-out-of-jail-free text), it's further evidence that a P90D coming off the line today has higher performance than an older P90D. The disclaimer text literally says that if I have an older P90D and pay $10,000 for the Ludicrous Mode upgrade, it will NOT have the same performance as a brand new P90D.

 

[fiksegts]

I know someone who just picked up a refresh P90DL with no pano roof and this person doesn't weigh much, he'll be at the track soon...

 

[stopcrazypp]

Lol. True. I guess my main point is that if the new disclaimer text was intentional (rather than just blanket get-out-of-jail-free text), it's further evidence that a P90D coming off the line today has higher performance than an older P90D. The disclaimer text literally says that if I have an older P90D and pay $10,000 for the Ludicrous Mode upgrade, it will NOT have the same performance as a brand new P90D.

That's true, but that's something we already knew from the logs gathered so far. The key question is if the P90DL (older and new version) can possibly meet the 10.9 1/4 mile claim. If this is possible, then it doesn't particularly matter that the newer ones perform better for the subject of that discussion.

 

[FlatSix911]

I know someone who just picked up a refresh P90DL with no pano roof and this person doesn't weigh much, he'll be at the track soon...

Sounds like a 10.9 car ... keep us posted.

See my previous two posts, where I've 'suttly' shifted my argument to efficiency.

'suttly' ... Slutty or did you mean subtly?

 

[NOLA_Mike]

this person doesn't weigh much

And now they weigh about $130k less...

 

[P85DEE]

Anyone else notice the Model S and Model X P90D Ludicrous Mode upgrade pages have added the same disclaimer text as the P85D Ludicrous Mode upgrade page? Specifically "The retrofit will not be an exact equivalent performance spec as a new P90D." Previously only the P85D Ludicrous Mode upgrade page had this disclaimer. The plot thickens...

Tesla — Ludicrous Mode P90D
Tesla — Ludicrous Mode P90D
Tesla — LUDICROUS MODE ONLY (P85D) - PRE ORDER DEPOSIT

Wow.

People make an issue of it when Tesla doesn't lower expectations, .....and now when Tesla does lower expectations it's still an issue.

They can't do a damned thing right.

 

[lolachampcar]

Yep....
We just bad peeeople P85DEE.

 

[TIppy]

@sorka, do you agree that the front motor because of its taller gearing is being forced to run at higher current and less efficiently? If so, I think it still makes sense to make as much power with the rear motor as possible since it does so more efficiently. This is what I'm trying to determine. What is the probable power split between the front and rear motors? Is it just in the ratio of there hp ratings, or is there something else that would alter this relationship? Since power in equals power out minus the conversion losses, it seems like efficiency is the only determining factor.

 

[P85DEE]

Yep....
We just bad peeeople P85DEE.

That's a bit harsh. I wouldn't say that.

But a bit too animated over .01517 seconds short of a 10.9999 well yeah.

But that doesn't make anyone a "bad" person.

 

[bhzmark]

And now they weigh about $130k less...

ha, that made me look: The lightest/fastest P90DL, one optioned only with Ludi and the weightless autopilot is $120k pre tax credit.

Although now they have a beefier center console. The fastest and lightest P90DL would be after the battery hardware upgrade but before the new center console -- if there was such car.

 

[sorka]

@sorka, do you agree that the front motor because of its taller gearing is being forced to run at higher current and less efficiently? If so, I think it still makes sense to make as much power with the rear motor as possible since it does so more efficiently. This is what I'm trying to determine. What is the probable power split between the front and rear motors? Is it just in the ratio of there hp ratings, or is there something else that would alter this relationship? Since power in equals power out minus the conversion losses, it seems like efficiency is the only determining factor.

If that were true, Tesla wouldn't be running only the front motor during "torque sleep" where they suspend the rear motor because the front motor is more efficient which is why the D cars get better wh / miles than the rear drive only cars.

 

[TIppy]

If that were true, Tesla wouldn't be running only the front motor during "torque sleep" where they suspend the rear motor because the front motor is more efficient which is why the D cars get better wh / miles than the rear drive only cars.

I think the difference there is that the beefier rear motor is not forcing the taller geared front motor to run at higher torque and current.

 

[sorka]

@sorka, do you agree that the front motor because of its taller gearing is being forced to run at higher current and less efficiently? If so, I think it still makes sense to make as much power with the rear motor as possible since it does so more efficiently. This is what I'm trying to determine. What is the probable power split between the front and rear motors? Is it just in the ratio of there hp ratings, or is there something else that would alter this relationship? Since power in equals power out minus the conversion losses, it seems like efficiency is the only determining factor.

Sorry. I realized I hadn't read the rest of your comment. I think the split all depends on what's happening.

When the car is cruising steady state on the freeway with range mode on, a feature called torque sleep activates under just the right conditions and puts the rear motor to sleep essentially leaving the car a front wheel drive car. The smaller motor is more efficient at highway speeds than the larger rear motor.

Under maximum acceleration, the torque is going to be split to increase maximum traction, i.e. as much torque in each motor that is possible before traction on either axle is broken.....at least up to about 45 MPH. Up to 45 MPH, the car is traction limited, not power limited. After 45 MPH, it's hard to say what it does at that point. I would imagine the acceleration for some period of time would be more biased towards the back. But if you're accelerating out of a corner, then it's going put as much power into the front as possible without compromising traction or stability. Unless someone can log the inverter power for each inverter I don't think anyone can say.

Any of you CANBUS loggers out there know if one of the busses breaks down power from front to rear? I vaguely remember someone posting a graph showing as such.

I guess it's time to get off my but and put my cable together for TM-Spy.

 

[Johan]

I think the difference there is that the beefier rear motor is not forcing the taller geared front motor to run at higher torque and current.

The rear and front motor likely have different RPM/speed/power bands/parts of the curve where they reach optimal efficiency. The front motor is likely more efficient at higher speeds than the rear motor.

 

[TIppy]

Sounds like a 10.9 car ... keep us posted.



'suttly' ... Slutty or did you mean subtly?

suttle
(ˈsʌtəl)
adj
an obsolete variant of subtle

I'm just very old.

 

[TIppy]

If that were true, Tesla wouldn't be running only the front motor during "torque sleep" where they suspend the rear motor because the front motor is more efficient which is why the D cars get better wh / miles than the rear drive only cars.

I've read that at highway cruise the model s requires only 14 hp. That's 2.8% of the rear motor hp and 5.4% of the front. Both are way over on the left of this efficiency plot. Because the rear motor makes so much more hp than the front, it is further to the left. This is probably why they just use the front motor for cruise. But this doesn't necessarily mean that when both motors are making max power that the smaller one is more efficient.

 

[lolachampcar]

P85DEE,
Humor my friend
Humor

 

[P85DEE]

P85DEE,
Humor my friend
Humor

Likewise my friend. Likewise.