Photo: @greentheonly via Twitter
Much has been written about the possibility of retrofitting HW3 Teslas with Hardware 4 computer and sensor suite. Although Elon Musk said it would not make sense economically to do it, it appears that the Hardware 4 computer is at least partly compatible with HW3 cars.
In January, Tesla announced the upgraded Hardware 4 computer and sensors during the Q4 2022 earnings call. It also said that the Cybertruck would feature the new hardware, although the Model S, Model X, and recently Model Y also got the new Autopilot brains. With what we've learned about the new components, thanks to a teardown performed in February, many potential Tesla buyers intended to postpone the purchase to get the new hardware. This was exacerbated because the new parts would not have been economically feasible to retrofit in older cars.
Since then, people buying an HW4-enabled Tesla reported that FSD software is incompatible with the hardware, and Tesla Vision only recently started to offer basic things like park assistance. The tides turned, and people suddenly weren't keen to have a HW4 car. But then, Tesla decided to install the new computer in the Model Y, and there weren't many options left for HW3 fans. That's when the HW4 computer became cool again, thanks to the promise of much better performance in the future.
People are again interested to know if the HW4 computer can be installed in the old cars sold with HW3. Although Elon Musk previously said it wouldn't make sense as the costs would be too high, some are still willing to try. The retrofit camp might get new hopes thanks to a recent finding by Tesla hacker Green (@greentheonly). Green received a Model Y HW4 computer "for some exploration" and tore it down as usual.
The most important takeaway is that Tesla did not modify the Model Y firewall to match the new hardware's cooling hoses. As you recall from the previous teardown Green performed in February, HW4 has the hoses further apart. Tesla used an adapter on the back of the module to install it in the Model Y with existing firewall cutouts. Since HW3 also used an adapter (see it in the gallery for comparison), Tesla's job was easy. What's more important is that, at least at the cooling level, the HW4 computer will be easy to retrofit in the old cars.
This still doesn't solve the other problems, including that HW4 relies on upgraded sensors and cameras, which might not be trivial to install. The wire harness is still different, and I'm sure there'll be other issues to sort out, so I think Elon Musk was right on this one. As we've learned recently, the HW4 computer in the Model Y is not the same as the one installed in the Model S/X, although the packaging is identical. Most obviously, there are depopulated areas on the PCB, and additional camera connectors are missing.
Since then, people buying an HW4-enabled Tesla reported that FSD software is incompatible with the hardware, and Tesla Vision only recently started to offer basic things like park assistance. The tides turned, and people suddenly weren't keen to have a HW4 car. But then, Tesla decided to install the new computer in the Model Y, and there weren't many options left for HW3 fans. That's when the HW4 computer became cool again, thanks to the promise of much better performance in the future.
People are again interested to know if the HW4 computer can be installed in the old cars sold with HW3. Although Elon Musk previously said it wouldn't make sense as the costs would be too high, some are still willing to try. The retrofit camp might get new hopes thanks to a recent finding by Tesla hacker Green (@greentheonly). Green received a Model Y HW4 computer "for some exploration" and tore it down as usual.
The most important takeaway is that Tesla did not modify the Model Y firewall to match the new hardware's cooling hoses. As you recall from the previous teardown Green performed in February, HW4 has the hoses further apart. Tesla used an adapter on the back of the module to install it in the Model Y with existing firewall cutouts. Since HW3 also used an adapter (see it in the gallery for comparison), Tesla's job was easy. What's more important is that, at least at the cooling level, the HW4 computer will be easy to retrofit in the old cars.
This still doesn't solve the other problems, including that HW4 relies on upgraded sensors and cameras, which might not be trivial to install. The wire harness is still different, and I'm sure there'll be other issues to sort out, so I think Elon Musk was right on this one. As we've learned recently, the HW4 computer in the Model Y is not the same as the one installed in the Model S/X, although the packaging is identical. Most obviously, there are depopulated areas on the PCB, and additional camera connectors are missing.
Tesla does not want anybody to open these anymore so they have this annoying sticker attached now.
— green (@greentheonly) July 31, 2023
On the other hand hose connectors are much easier to remove than in hw3, yay! pic.twitter.com/HKjis01SZK
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