Elon Musk deletes twitter posts about P85D/85D efficiency increases

[jerjozwik]

that blog post and subsequent update to the "how far i can go" have been very helpful. look forward to you all getting your software update.

see what happens when a bunch of people have too much time [holidays] and not enough information?

 

[3mp_kwh]

Well, with the blog post we have some rules.

"The software update to implement torque sleep will be downloaded to the dual motor fleet by the end of January 2015 and will substantially improve the range of dual motor vehicles by roughly 10%."

1 - Take your "concensus P85D" empirical 65mph range, and add 10%.

"if a standard Model S 85 with 19" tires having 265 miles of range is changed to 21" tires the range would be reduced by ~3% to about 257 miles."

2 - Adjust up 3% for 21's, as most folks who've reported aren't on 19's.

Working the other end, from 285 miles, the expected range of the testers becomes (.9)(.97)(285) = 249 miles. Did they achieve more/less than this?

"It is also worth noting that all new tires have a break in period for the first ~1,000 miles where the total vehicle efficiency is reduced by up to 5%."

Really? Underinflation, maybe, but that's a huge swing for same tire, same pressure, after only a few miles. By the time the update hits, the tires will be broken in. Then, hopefully the gap will be down to a gimme.

 

[jerry33]

Really? Underinflation, maybe, but that's a huge swing for same tire, same pressure, after only a few miles. By the time the update hits, the tires will be broken in. Then, hopefully the gap will be down to a gimme.

Underinflation can reduce it far more than 5%. How much the break-in period subtracts depends a lot on the tire.

 

[jerjozwik]

not sure about regular car tires, but my track ready tires need to be broken in before i can get mega grip.

 

[JBrown4390]

Just curious, How about the top speed? Is it also going to be corrected with the software update?

 

[Muskol]

For those that read the blog post shortly after it was published, there's some new info added in response to some questions asked in the comments.

Driving Range for the Model S Family | Blog | Tesla Motors

 

[FredTMC]

Um. Wow

 

[scottf200]

For those that read the blog post shortly after it was published, there's some new info added in response to some questions asked in the comments.

Driving Range for the Model S Family | Blog | Tesla Motors

Answers to Common Questions
Q: Which drive unit is able to sleep, front or rear?
With the P85D we put the large, rear, drive unit to sleep while cruising. We choose to sleep the rear unit since the new generation small front drive unit is actually more efficient at converting battery DC electricity into mechanical shaft power. So we benefit from using the small, front drive unit more of the time when it can provide all of the torque requested. In the 85D both drive units are the same and we can sleep either unit, front or rear to best optimize efficiency.

Q: Are standard or cyclone 19" wheels more efficient?
Cyclone 19" wheels are slightly more efficient than the standard, base, 19" wheels. This efficiency gain comes from an aerodynamic improvement of the wheel itself and the 19" tire effects are separate. The aerodynamic benefits are most pronounced at higher speeds so you will see the biggest gains at 65mph or 75mph cruising. For instance, the 19" Cyclone wheel gives roughly 2% more range than the 19" standard wheel at 65mph. The difference will be less than 1% in city driving however.

Q: What are the best 19" tires?
The Michelin Primacy 19" tires give roughly 3% more range than the Goodyear 19" tires at 65 mph. The difference is greater, up to perhaps 5% difference in range, in slower city driving. We do not have any suitable production tires better than the Michelin Primacy to offer yet but are constantly evaluating and testing new options. Many tires claim larger improvements than we actually see in real world testing so beware of aftermarket label specifications. Tires are an area of increasing focus for us as a company.

Q: Do wheel mass differences contribute to range differences?
The mass differences between the various wheel and tire options are quite small. The variance in range is created from rolling and aerodynamic differences between them. (see answers above)

Q: Will we offer a dedicated Aero Wheel design again?
The customer take rate on our previous Aero Wheel design was so low that we could not justify continuing the production and supply chain complexity of it. In general we are working to simplify the complexity of options available and eliminate those where we see fewer than 1/20 people choosing an option. In addition, the newer Cyclone wheel captures much of the aerodynamic benefit of that the dedicated Aero Wheel design did over the standard, base 19" wheel.

 

[scaesare]

"It is also worth noting that all new tires have a break in period for the first ~1,000 miles where the total vehicle efficiency is reduced by up to 5%."

Really? Underinflation, maybe, but that's a huge swing for same tire, same pressure, after only a few miles. By the time the update hits, the tires will be broken in. Then, hopefully the gap will be down to a gimme.

I had to replace a pair of tires after a puncture after only ~20K miles. Even though it was only two tires out of the set of four, and the exact same brand/model tire, my energy usage immediately went up by closer to 7-8% on average. I was convinced something was wrong until it settled right back down after some miles went by...

 

[dhanson865]

I'm surprised that the cyclone 19" gives better range than the standard 19". I'd rather have the old Aero wheels but I suppose the cyclones are the next best thing.

Still $2500 for 2% range increase is pretty steep when you consider that the upgrade from 60 to 85 kwh for $10,000 gives you about a 27% increase in range.

 

[Vger]

I had to replace a pair of tires after a puncture after only ~20K miles. Even though it was only two tires out of the set of four, and the exact same brand/model tire, my energy usage immediately went up by closer to 7-8% on average. I was convinced something was wrong until it settled right back down after some miles went by...

I noticed this also for the same reason. I just did not know what it could be due to. I am so glad to know! BTW, this illustrates how sensitive we have all become to the nuances of efficiency. The instrumentation on a Tesla is so much better than any ICE that one notices things like this that would have drifted by (or have been drifting by) our whole previous motoring life.

It is good to hear that JB's team is putting a lot more attention on tires going forward. This is probably one of the benefits of hiring Chris Porritt from Aston Martin!

- - - Updated - - -

And now I just remembered that the EPA range, while commonly quoted as a single combo number, includes city and highway numbers - and the P85D highway numbers ARE better than those of the P85. So...it seems likely that P85D performance will improve? But how did they get that rating if it doesn't meet it now? It's all so confuzzling. Like everybody else, I'm looking forward to a blog post explaining it all.

Ask and you shall receive! You must have posted this moments before the blog came out! :smile:

I think your explanation is reasonable, and I would add an additional nuance. Like the sleep feature, I think they probably had torque sleep working in prototype form and thought they would have it for first ship. Then they may have discovered some subtle problems with it (we know Elon is a perfectionist) and held it back for more work. Hence the floodgates of doubt and dismay, and an evolving communication response.

In my imagination, I can hear Ricardo Reyes saying at an exec staff meeting, "We need to get a full blog out on this. We should have JB do it, like he used to do more of, when I was here before. His credibility is impeccable."

 

[dennis]

In my imagination, I can hear Ricardo Reyes saying at an exec staff meeting, "We need to get a full blog out on this. We should have JB do it, like he used to do more of, when I was here before. His credibility is impeccable."

If that's the way it happened it would bode well for the future.

 

[jerry33]

I'm surprised that the cyclone 19" gives better range than the standard 19".

The blog post was a bit disingenuous about the Areo wheels. 20-1 is great ratio considering how little time they were available as an option. I would have ordered them if I had been able to. And then when they were in the Accessories tab, they were tied to the Pirelli tires which I didn't want.

 

[Todd Burch]

The blog post was a bit disingenuous about the Areo wheels. 20-1 is great ratio considering how little time they were available as an option. I would have ordered them if I had been able to. And then when they were in the Accessories tab, they were tied to the Pirelli tires which I didn't want.

What was disingenuous about it? Tesla said they didn't want to offer an option that 5% or less of people opted for, so they canned aero wheels. I believe the demand for the aero wheels was quite a bit less than 5%...and understand why it was canned.

 

[jerry33]

What was disingenuous about it? Tesla said they didn't want to offer an option that 5% or less of people opted for, so they canned aero wheels. I believe the demand for the aero wheels was quite a bit less than 5%...and understand why it was canned.

The Areo wheel was almost never available as an option in the Design Studio. Kind of hard for it to be a hit when you couldn't place an order.

 

[dhanson865]

The Areo wheel was almost never available as an option in the Design Studio. Kind of hard for it to be a hit when you couldn't place an order.

Kind of like the S60D that wasn't on the store for more than a month or two? Nice to have the extra options but they are very quick to drop the option entirely instead of just adjusting the price to increase demand.

Do we really believe they couldn't drop the price any on Aero wheels to spur demand. Couldn't they leave the option on the table for a few more months to give more people time to order? The normal company response to low demand is to put the item on sale (clearance or otherwise) and let lower prices move the product.

I sure hope they aren't so quick to kill options in the first year of the Model 3. It'll take a while for people that don't want to be first to take it seriously and if you gauge demand based on early adopters you'll have skewed demand data not representative of the general market.

 

[Krugerrand]

Kind of like the S60D that wasn't on the store for more than a month or two? Nice to have the extra options but they are very quick to drop the option entirely instead of just adjusting the price to increase demand.

Do we really believe they couldn't drop the price any on Aero wheels to spur demand. Couldn't they leave the option on the table for a few more months to give more people time to order? The normal company response to low demand is to put the item on sale (clearance or otherwise) and let lower prices move the product.

I sure hope they aren't so quick to kill options in the first year of the Model 3. It'll take a while for people that don't want to be first to take it seriously and if you gauge demand based on early adopters you'll have skewed demand data not representative of the general market.

And there we go again, assuming the worse for why a decision was made.

 

[Beavis]

Kind of like the S60D that wasn't on the store for more than a month or two? Nice to have the extra options but they are very quick to drop the option entirely instead of just adjusting the price to increase demand.

Do we really believe they couldn't drop the price any on Aero wheels to spur demand. Couldn't they leave the option on the table for a few more months to give more people time to order? The normal company response to low demand is to put the item on sale (clearance or otherwise) and let lower prices move the product.

That only works if you have slow moving inventory that you need to get rid of to make room for the new stuff. That was not Tesla's problem. The logistics and start up manufacturing cost spread over a small number of parts made continuing to offer the aeros a bad business decision.

 

[dhanson865]

And there we go again, assuming the worse for why a decision was made.

You think that was the worse explanation or the worst? I could imagine much worse, I didn't go into Tesla is a bad company territory or conspiracy theories. I was just explaining consumer expectations. You apparently see something bad about average behavior.

I'm still pro Tesla to be sure. I just want them to not focus on the rich tech centric early adopter when they try to make a mass market car in a couple of years.

 

[jerjozwik]

Kind of like the S60D that wasn't on the store for more than a month or two?

i thought they killed the S60D to streamline the production process, same with the brown and green paints.