Auto engineer Sandy Munro of Munro and Associates has wrapped up his Model Y teardown and the final verdict is that Tesla’s latest electric car is, quite simply, “absolutely stunning” and a testament to the continuous improvement and innovation the EV maker is achieving.
In a wrap-up – though not quite final – video (see link below) on what he and his team have discovered about Model Y, the auto industry veteran shares his top 10 takeaways and says other car makers had “better take note”.
Munro points to Tesla’s unique approach of making incremental improvements to its electric vehicles, as opposed to other carmakers that tended to add improvements in one big batch.
“This car should be a wake-up call for anyone who’s manufacturing anything regardless of whether it’s a cell phone or a car or an aeroplane or anything else in the marketplace,” he said.
Top of the list is the Model Y’s rear casting, which CEO and co-founder Elon Musk flagged as a major step-change in manufacturing the Model Y at the company’s first-quarter earnings call.
“The mega casting represents a significant jump in innovation when it comes to body structure,” says Munro.
“We’ve seen many other OEMS use smaller cast notes throughout a vehicle, specifically in the rear quarter and front shock towers but nothing at this scale,” he says.
Significantly, the casting spans the full width of the body, says Munro.
“Tesla’s talked about combining the two existing castings into one and potential even incorporating more more than one into the forward body and that single casting will be definitely a game-changer.
“There are definite advantages to be had in pursuing this but it’s definitely unchartered territory when it comes to the tooling complexity cost in the physics associated with executing this.
“The one thing that I will tell you is that they probably are going to be successful and the reason is because they are creating their own aluminium – they’re creating new material, science that no one else has in so that’s consequently why they can make these things happen.”
This is where Tesla has made huge jumps in quality improvements, says Munro, who was extremely critical of the Model 3’s weld jobs.
“This is the body of a model Y and we were specifically looking at things on the other one like sloppy welds, unnecessary high panel counts, too many fasteners.
“We’re seeing lessons learnt on the Model Y, put into practice with notable improvements in weld consistency and spacing and we love seeing the switch to the composite tub in lieu of the hundred-plus pieces of stamped assembly,” says Munro.
We did find some splash welds on the side of the body as well as a few questionable welds on the shotgun and the shock towers but it was a substantial improvement over the Model 3.”
Fit and Finish
“Every rose has its thorn,” said Axl Rose, and for the Model Y that thorn is, unfortunately, the fit and finish.
“It exhibits some significant issues with fit and finish. The paint has evidence of orange peels and runs,” says Munro.
Asymmetrical features especially on the tail lamps and lift gate, and structural elements that defined the safety and functionality of the vehicle stood out to Munro.
“Although we did feel that the vehicle is a vast improvement over the Model 3, the fit and finish really needs to be still addressed.”
A novel way of wiring to significantly reduce labour costs, such as was hinted at in this patent, did not bear out with the Model Y unfortunately.
“This is an area that I was really really excited about,” says Munro.
“There is a tremendous amount of buzz associated with the wiring but unfortunately we didn’t get the chance to see the kinds of things that we were hoping for. We were sort of interested in how we are going to see this next gen of wiring.”
But when Munro and his team got behind the panels, they found it is “relatively efficient in terms of bundle size and packaging … it was still conventional in nature.”
While Tesla has gone down from about 1.5km wiring to just 700 metres, he says it was not as much of an improvement as had been hoped for.
“Nice job but not revolutionary,” says Munro.
The heat pump on the other hand, as we covered here, is a big improvement due to its reduction of power load from accessories – heating and cooling in particular.
“The addition of the heat pump to me was was a very efficient use of power, [a major] consideration when you’re in the world of EVs,” says Munro.
“The less power you use for accessories means more range… although many might not realise it, the HVAC system draws a significant amount of power and in pursuing a heat pump system, Tesla sought to eliminate high voltage movement,” he says.
Munro points out that Tesla is not the first OEM to use a heat pump in an EV, as Nissan has already done so with its Leaf.
But, “they definitely took the idea to new heights in their version of the system,” he says.
“We were impressed with a super bottle system we saw in the Model 3 … but the latest iteration [in the Model Y] with the octovalve in a heat pump definitely represents a step forward in terms of innovation and integration,” he says.
This is a significant inclusion in Munro’s dissertation on the Model Y, given that there will now be an even longer wait for Battery Day.
“In the [previous] video before I said that we figured they were the same,” he says.
But, having taken a closer look at the battery cells, Munro noted some minor differences from the cells in the Model 3, and so has asked his engineering team to dive deeper.
“We think that the chemistry here is a little different which makes the cell little bit cheaper and that that’ll be information it’ll come down the pipe later on.”
Munro notes that Tesla has already made several improvements in its battery packs from eliminating fasteners to simplifying covers, to eliminating more than half of the temperature sensors.
“These changes might seem trivial to the casual observer but they are indicative of a mentality and engineering culture that serious about reducing costs wherever possible. They still maintained all of the functionality however – the deal with Tesla is that they’re serious about it.”
The Model Y headliner – the molded material that is stuck to the inside of the roof in a car – is also an improvement.
Unlike the Model 3, which like other vehicles has a headliner made with glass fibre and compression-molded, Tesla has taken a different tack with the Model Y.
“One of the most striking features of the Model Y is its panoramic glass roof with no body-cross members,” says Munro.
“But this more obvious feature coupled with the pretty unique headliner solution …. was basically unlike anything we’ve ever seen.”
“They opted to utilise injection-molded plastic construction rather than conventional thermoset cardboard or fibre construction like it was on the 3.
“They realises some major benefits in terms of improved manufacturability …. they made the assembly that’s going to be much easier for the technicians to install without having to worry about creasing or folding the substrate.
“They also made the entire assembly a two-piece component which will involve some massive and expensive moulding tools but which is probably justified considering it affects 100% of their volume and offers the afore-mentioned savings and time and assembly.
“Not only that, it looks nice,” says Munro.
By this, Munro refers to the fact that Musk said the Model Y would basically be three-quarters the same as the Model 3. This allows Tesla to reduce retooling costs, and capitalise on production experience from the Model 3.
“Tesla was vocal about their intention to keep as much of the Model Y components common with a 3 and we have seen some serious commitment to this,” Munro says.
“Volkswagen has long been the front runner in terms of commitment to savings through commonisation …. Kia, Hyundai and Toyota also share that same mindset but even for them something 75% to be an incredible to share between a sedan or SUV,” he says.
At the end of the day what we did see a lot of common components – we’re not sure whether it’s actually hit 75% in terms of literal parts, but maybe we believe that it might have been achieved with respect to the cost of their components.”
According to Munro, Tesla has cleverly changed out the interior components of the Model Y motor – in particular the expensive copper rotor – and kept certain external features to ensure no need to change other related assembly parts.
“Even though the front induction motor featured the same external housing in geometry that we saw in the Model 3, we realised once we got a look at the rotor they had made some changes inside,” he says.
“Tesla substituted the vacuum brazed copper rotor …. for a cast-in-place aluminum assembly. This reduced cost while maintaining the functionality and critically maintain the same envelope which is basically re-enabling the use of the surrounding components,” he says.
They also managed to eliminate a lock nut further reducing weight and thereby improve efficiency.
The Major Takeway
Munro’s major takeaway – and which he cannot even fully comment on yet – is the computer board for the Model Y. As we know, Tesla is now using Hardware V3x in new Model 3s and Model Ys, and the new hardware is so complex Munro’s engineers are still working out how to take it apart.
“This is what I would classify as my major takeaway,” he says, with a v2.5 board (pre-Tesla AI chip) in his hand.
“This board here is for Autopilot, this would be rated at about a 2.5, the other one is rated as a 3.
“If you think this is densely populated …. remember that Tesla has decided to invent their own chip, and that is giving our guys fits trying to figure out how this thing works, and how they going to take it apart, and how we decap, and how we x-ray and on and on and on.
“So it’s going to take us a while before we can show you the board from the Model Y,” says Munro.
“We’re going to probably have to wait for a while before my guys can get that done. But this is my major take away – everything electronic for Tesla is absolutely stunning.”
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Bridie Schmidt is lead reporter for The Driven, sister site of Renew Economy. She has been writing about electric vehicles since 2018, and has a keen interest in the role that zero-emissions transport has to play in sustainability. She has participated in podcasts such as Download This Show with Marc Fennell and Shirtloads of Science with Karl Kruszelnicki and is co-organiser of the Northern Rivers Electric Vehicle Forum. Bridie also owns a Tesla Model 3 and has it available for hire on evee.com.au.