EVFan3939's avatar
4d

Telsa HW3 to HW4 Upgrade is hard

A facebook post discussing the HW3 to HW4 upgrade and how painful it is explaining why Tesla will never do it officially.  No link or background so take it for what its worth.

For you HW3 guys,  would you try the upgrade or just trade up to a HW4 car?

The first successful conversion of a Hardware 3 Tesla to Hardware 4 is complete, with a 2022 Model 3 now running FSD Supervised v14 on upgraded hardware. The work was carried out independently by enthusiasts rather than Tesla, and it required considerably more than swapping a computer. Alongside the HW4 unit itself, the project involved ECU modifications, camera adapters, different camera mounts, headliner modifications, and a full windshield replacement. The builder described the process as a nightmare after the early optimism that followed the initial attempt, when it appeared the camera cabling could be reused and the job might prove straightforward. Some refinement work remains outstanding. The achievement is genuine, demonstrating that HW3 vehicles can technically run the newest software stack given enough effort. What it also demonstrates is why Tesla is unlikely to offer this as a paid upgrade. A retrofit requiring windshield replacement and interior disassembly across roughly four million vehicles presents a service burden that would be difficult to justify commercially.

https://www.facebook.com/search/top?q=tesla%20hw3%20to%20hw4

Sep 13, 2026
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alsancle avatar
· 4d

There is a 10k premium right now apples to apples on HW3 vs HW4.  Year older but same mileage.   There was not cost or hours associated with this post so it is hard to tell how real it is.

My guess is that people that want HW4 buy new and trade up.   I'm on the fence as I want an S.  The used inventory for the S has dried up since they stopped building them in June.

TeslaFan01 avatar
· 4d

If they could do the upgrade for under 3k I would sign up.   But after that I'm thinking of upgrading the entire car.  I have buddies not buying new because they think HW5 is imminent.  That is a treadmill that will never end.

tbrow avatar
· 3d

I recently traded my HW3 Model 3 for a HW4 Model Y.   There was a 20k different which I financed.   The HW3 FSD  works ok.  The HW4 FSD works fantastic.   My advice it to trade up.    The Model Y feels different than a 3 being bigger and I'm getting used to that.  But the FSD is game changing.

alsancle avatar
· 3d

Maybe you can do a first person review of the HW4 FSD?