Sandy Munro talks about the teardown of the Model 3

[voip-ninja]

Based on everything I've seen and read, I think it's a little bit of both. Like you pointed out, Tesla was able to remove a bunch of welds with no appreciable impact on production that anyone is aware of, and like Sandy pointed out, certain parts of the car like the trunk have been a little bit of a mess in terms of design/assembly.

With that said, Sandy may be correct to point out that the frame alone is enough for current crash testing requirements/ratings, and that Tesla could save $600/car by optimizing their design, but may still be missing how much Tesla wants to protect the battery pack because of consumer sentiment. Because of the amount of FUD out there, it may be financially worthwhile for Tesla to spend an extra $600 and build a body that is an order of magnitude better at protecting the pack even if the difference is practically speaking very small.

The problem is;

1. We don't know that treating the battery pack as a structural member in crash testing necessarily impacts battery survivability in a crash.
2. Tesla have never said that above and beyond protection of the battery pack was a design goal, that has merely been speculated.

 

[wsucougz]

What strikes me most about this video is that Sandy is sounding more and more like a Tesla "fanboy" every day. The fit/finish and frame will get sorted out where necessary. In basically every other area, he confirms they are mopping the floors with the competition and breaking further away from the pack. He is clearly astonished by what they are doing. Sometimes I wonder if we are missing something -- he is confirming a lot of what folks on TMC have known/speculated on for some time. The competition is screeeewed.

"Tesla has zero competitive advantage" -MB Spiegel

 

[voip-ninja]

What strikes me most about this video is that Sandy is sounding more and more like a Tesla "fanboy" every day. The fit/finish and frame will get sorted out where necessary. In basically every other area, he confirms they are mopping the floors with the competition and breaking further away from the pack. He is clearly astonished by what they are doing. Sometimes I wonder if we are missing something -- he is confirming a lot of what folks on TMC have known/speculated on for some time. The competition is screeeewed.

"Tesla has zero competitive advantage" -MB Spiegel

People are upset when there is any criticism of Tesla.

You must be new here.

 

[moridin2002]

Not sure if anyone else has mentioned it already, but Sandy keep complaining that the Model 3 unibody is poorly engineered because it's heavier than it needs to be. TBH he seems confused by Tesla's largely novel use of high strength steels in the body to create a sort of steel composite that has varying stiffness and strength properties in different places in order to more effectively dissipate crash energy, particularly from the sides of the car.

High strength steel has been used in relatively limited ways in cars before, particularly in a few places in front crash structures, but the side crash structures that Tesla uses may be new in the way they make a composite of various different high strength and mild steels in different locations. For example the A, B, and C pillars have prominent vertical pieces of high strength steel, and door tie beams made of HSS tying the pillars together through the door panels. The HSS pillars blend into lower strength, but more deformable steel pieces progressively (e.g., through spot welds). This probably creates a progressive crash structure that can dissipate much energy in a very short distance by distributing the force from the stiff and strong HSS beams to the softer more ductile and malleable mild steel. If so, this is a brilliant design.

(Mild steel has an advantage over HSS in being able to absorb energy by deforming and stretching more. Stiffer steels on their own will break before they bend. Mild steel will bend before it breaks. In engineering language mild steels ultimate tensile strength is significantly higher in relative terms than its yield strength. Combining HSS and mild steels may result in a composite that improves crash performance synergistically. The HSS is like a backbone that transfers crash energy to the mild steel (where it's absorbed by deforming) while keeping the general structure mostly intact.)

And Sandy doesn't seem to understand it, based on his repeated ignorant/confused/derogatory comments about it.

For example, he claims in the video above that existing CAD software marks many parts of Tesla's metal body to be unnecessary. Most likely the CAD software was not designed to use a composite of different steels in this way. It too may be ignorant.


The result for Model 3 is superb crash performance from pretty much any direction. In fact, it's world best in most testing. Some of that could be due to novel engineering of steel composites. And that novel use of steel in turn could be due to novel use of CAD technology.

Most of Tesla's advances are likely due to software, not just in obvious places like Autopilot, but also in car design software, battery testing software, chemical design software, etc. As a Silicon Valley company Tesla seems well aware of the importance of software in all aspects of the products.

Companies (other than Tesla) have been using mixed high strength steels for awhile now. Front offset overlap protection essentially mandated their inclusion in designs to maintain occupant cell integrity during those impacts without adding significant weight. With that said, Sandy Munro and his team most certainly understand that as they've been benchmarking and pulling apart vehicles (specifically body in whites) for decades. They've most certainly done newer vehicles (like the BMW 3 Series he has data points for) during the discussion.

 

[Garlan Garner]

Seriously? I spent a pile of my time in the mid 80's racing early superbikes on skinny 130's. The only way we could get those bikes into the 10's was by reducing weight. And oh yeah, they were traction limited with those skinny rock hard tires which you could smoke at will. And this applies directly to 4 wheels. And yes, I have done this as well.
So yes, reducing mass changes acceleration. In racing this a proven fact.
How many race cars have you built? Or perhaps bikes?

The only problem is that quickness isn't the sole or primary objective of a Tesla.

If you remove anything from a Tesla it changes/reduces other objectives.

Teslas are less race cars than many of their other objectives.

The only reason why we are talking about the quickness of Teslas is because they are quick - without that being their primary objective.

That's amazing to me. To keep talking about the quickness of a superiorly safe - self driving family sedan. LOL

 

[Garlan Garner]

How long will a Tesla last?

10 years? 20 years? 30 years?

If you make a car to last 30 years @ maybe 500K miles in Chicago's pothole ridden streets.....how many welds are useless?

Yes - the welds might be overkill on the track.
Yes - the welds might be overkill if you only drive the car a total of 40k miles in its lifetime.
Yes - the welds might be overkill if you are never in a crash @ 70mph.
Yes - the welds might be overkill if...…..

 

[moridin2002]

You still aren't listening.

If you make all of those modifications you mentioned....then the car would be more expensive.

What modifications can you make that won't change the price?

I haven't built any cars myself, however I do cost analysis EVERY DAY on production and manufacturing.

For goodness sake..you could probably replace a lot of things on the Model 3 with carbon fiber....but can you do it with no up-charge.

Keep in mind that Tesla's don't have one purpose and the least likely purpose is being a track car.

Tesla Model 3's are safe / fast / quick / safe / family sedan / tech savy / safe / attractive / self driving / affordable ( for some ) / etc.... What modification can you make to improve the Model 3 and NOT change any of the factors that I listed?

You may do cost analysis every day, but how is your knowledge-base in engineering and the manufacturing of automobiles? A vehicle is not a single component or small subset of components, its the entire system. Sometimes, adding cost to one area by using a more expensive part in one area, can reduce complexity in another (see Super Bottle discussion by Sandy Munro). Making a lighter, less material intensive, more easily produced body in white (BIW) would reduce cost from manufacturing and material usage perspectives, actually utilize the battery pack as a stressed member, and improve efficiency of the vehicle due to less mass which could reduce battery pack size (and lots of cost) for a targeted range.

The one area you're also missing is that Munro worked with Siemens to structurally test the Model 3's chassis. There's a report with the data of those tests available for purchase. They aren't hiding it. If a vehicle has a stressed member (the battery pack in this case) that adds no stiffness to the BIW when it is installed, the BIW is overbuilt. That conclusion is even more clear when the BIW in question is much heavier than best-in-class BIWs from other manufacturers. There is also such a thing as making a structure too stiff for an intended application. Try a helmet made of steel and one made of EPS.

Your pejorative of Munro's name is quite childish and detracts from your credibility to make a well received counter argument. The man gave his opinion based on empirical data with loads of experience to back it up.

 

[Garlan Garner]

You may do cost analysis every day, but how is your knowledge-base in engineering and the manufacturing of automobiles? A vehicle is not a single component or small subset of components, its the entire system. Sometimes, adding cost to one area by using a more expensive part in one area, can reduce complexity in another (see Super Bottle discussion by Sandy Munro). Making a lighter, less material intensive, more easily produced body in white (BIW) would reduce cost from manufacturing and material usage perspectives, actually utilize the battery pack as a stressed member, and improve efficiency of the vehicle due to less mass which could reduce battery pack size (and lots of cost) for a targeted range.

The one area you're also missing is that Munro worked with Siemens to structurally test the Model 3's chassis. There's a report with the data of those tests available for purchase. They aren't hiding it. If a vehicle has a stressed member (the battery pack in this case) that adds no stiffness to the body in white when it is installed, the BIW is overbuilt. That conclusion is even more clear when the BIW in question is much heavier than best-in-class BIWs from other manufacturers. There is also such a thing as making a structure too stiff for an intended application. Try a helmet made of steel and one made of EPS.

Your pejorative of Munro's name is quite childish and detracts from your credibility to make a well received counter argument. The man gave his opinion based on empirical data with loads of experience to back it up.

The man changed his mind.

His first analysis was asinine. They he did a second one and it was better and closer to actual facts than opinion.

I'm waiting for the third that is closer to reality.

Until then....you can call me as many names as you like. LOL.

 

[mongo]

The one area you're also missing is that Munro worked with Siemens to structurally test the Model 3's chassis. There's a report with the data of those tests available for purchase. They aren't hiding it. If a vehicle has a stressed member (the battery pack in this case) that adds no stiffness to the body in white when it is installed, the BIW is overbuilt. That conclusion is even more clear when the BIW in question is much heavier than best-in-class BIWs from other manufacturers. There is also such a thing as making a structure too stiff for an intended application. Try a helmet made of steel and one made of EPS.

The S is barely self supporting without the pack and we don't know what the form factor of the SR pack will be.
Being structurally pack independent may have been a deliberate design choice.

 

[moridin2002]

This isn't a court of law, proof isn't necessary. What we need is common sense, something that Munro is lacking. He was biased from the get-go with the panel gap variations. But that is primarily a manufacturing problem, not an engineering/design problem.

I know for a fact that Tesla engineers used structural design engineering software to simulate not only chassis stiffness but also crash safety and load transfer. They had certain goals in mind. I also know that Munro didn't - he is simply noting that the Tesla structure is more over-built compared to the cars he's torn down in the past. He assumes what was "good enough" for them is good enough for the Model 3. But he didn't do the calculations and I'll note the other cars didn't have 1/2 ton of battery slung underneath.

He admits the Model 3 handles exceptionally well, as if it were on rails, but cannot explain why it handles better than other cars he's tested. Common sense says Munro is out of his league here compared to the brilliant minds that engineered the chassis that handles so well. All he can see is that it's different and the panel gaps are not consistent. I also wouldn't be surprised if he's not a little butt hurt that they didn't want to hire him.

I'm not saying the Model 3 can't be improved and refined over time but I hope Tesla doesn't ruin it and make it average by bringing in the bean counters to tell them they can save $1 here and a $1 there. Because I really do think driving dynamics and safety are things people are willing to pay a few bucks for on a mass market car. But to assume, as Munro did, that different is BAD is ridiculous in the extreme because he didn't even look at the computer simulations that were used to custom design the structure to begin with.

After taking delivery of our first Model 3 I saw that it was a cut above and didn't know how long the introductory version would be available without the bean counters getting their fingers in the pie. So I ordered a second one right away.

Except Siemens actually tested the chassis for Munro and can back up the argument.

 

[ricohman]

The only problem is that quickness isn't the sole or primary objective of a Tesla.

If you remove anything from a Tesla it changes/reduces other objectives.

Teslas are less race cars than many of their other objectives.

The only reason why we are talking about the quickness of Teslas is because they are quick - without that being their primary objective.

That's amazing to me. To keep talking about the quickness of a superiorly safe - self driving family sedan. LOL

You keep moving the goal posts so I no longer have any idea what you are talking about.
Just no more talk about racing please.
The 3 is a zippy car. It is what got me interested in it in the first place.
And the eCOPO Camaro will soon be here in one form or another. And that power unit will be sold as a crate motor to bolt into any TH400 project lying around. Electric drag cars are here already and they are here to stay.

 

[voip-ninja]

The man changed his mind.

His first analysis was asinine. They he did a second one and it was better and closer to actual facts than opinion.

I'm waiting for the third that is closer to reality.

Until then....you can call me as many names as you like. LOL.

He hasn't once changed his mind about the unibody of the car being seriously overbuilt.

I don't think you understand how they would have tested the Model 3 body. The body would have been 3D scanned and fed into specialized software designed to provide stress analysis. Munro's comment that "the whole thing is blue, there are no stress point" means that Tesla either intentionally made a wastefully overbuilt design or they got it wrong.

At least they erred on the "overbuilt" side of things vs underbuilding the car.

 

[moridin2002]

The man changed his mind.

His first analysis was asinine. They he did a second one and it was better and closer to actual facts than opinion.

I'm waiting for the third that is closer to reality.

Until then....you can call me as many names as you like. LOL.

Incorrect. Munro has never changed his mind on the BIW design. He has been consistent with that in every interview.

 

[Garlan Garner]

Tesla is using R1234yf to cool the cabin and the motors?


You keep moving the goal posts so I no longer have any idea what you are talking about.
Just no more talk about racing please.
The 3 is a zippy car. It is what got me interested in it in the first place.
And the eCOPO Camaro will soon be here in one form or another. And that power unit will be sold as a crate motor to bolt into any TH400 project lying around. Electric drag cars are here already and they are here to stay.

I'm not moving any goal posts.....LOL.

That's always the statement made around this time in the discussion.

I had the same debate after his first analysis with people here.


Then he "changed his mind" and adjusted his analysis...

Now the same thing is happening again.

I'm not surprised.

 

[Garlan Garner]

Incorrect. Munro has never changed his mind on the BIW design. He has been consistent with that in every interview.

I don't understand why you guys are hanging on his every word. This is amazing to me.

 

[moridin2002]

The S is barely self supporting without the pack and we don't know what the form factor of the SR pack will be.
Being structurally pack independent may have been a deliberate design choice.

If that's true, its a poor design choice with the pack being as stiff as it is and the way its mounted to the chassis. Added weight and cost for no benefit.

 

[Garlan Garner]

If that's true, its a poor design choice with the pack being as stiff as it is and the way its mounted to the chassis. Added weight and cost for no benefit.

"IF" its true?

Haven't you guys already concluded that it is true? For goodness sake...they guy said it was true.

 

[StealthP3D]

The problem is;

1. We don't know that treating the battery pack as a structural member in crash testing necessarily impacts battery survivability in a crash.

Common sense says if the battery pack absorbs some of the crash energy it has a higher chance of being damaged. To deny that is silly.

2. Tesla have never said that above and beyond protection of the battery pack was a design goal, that has merely been speculated.

Common sense says that if the battery pack is not a stressed member of the chassis that protection of the battery pack was a design goal.

I'm amazed at the lack of critical thinking that passes as analysis here.

 

[voip-ninja]

I don't understand why you guys are hanging on his every word. This is amazing to me.

We're not "hanging on his every word", we recognize that he's an industry expert and has a ton of experience building cars and now taking them apart. He and his engineers have taken apart all of the class leading cars and are in a better position to make these comparisons than anyone else... especially in the area of body assembly as that is the actual area of vehicle fabrication that Munro himself has been involved in for 30 years.

 

[Garlan Garner]

We're not "hanging on his every word", we recognize that he's an industry expert and has a ton of experience building cars and now taking them apart. He and his engineers have taken apart all of the class leading cars and are in a better position to make these comparisons than anyone else... especially in the area of body assembly as that is the actual area of vehicle fabrication that Munro himself has been involved in for 30 years.

Name something that you think he said that was wrong. I'll wait......

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