Holy Grail Labs offers a retrofit kit for classic BMW E12, E23, E24, and E28 models that replaces outdated torpedo fuse holders with a direct‑fit circuit board for modern blade‑style fuses.
Funding
Funding not disclosed
Founders
Product
Problem
Classic BMW E12, E23, E24, and E28 models use outdated torpedo (bullet) fuses that develop high resistance, lose spring pressure, and can melt, leading to unreliable electrical performance and frequent fuse failures.
Solution
The Holy Grail Labs retrofit kit replaces the original torpedo fuse holders with a custom circuit board that accepts modern blade‑style fuses. The new board reduces overall circuit resistance, eliminates spring‑pressure loss, and includes LED indicators that show green when power is present and red when a fuse is missing or blown (with an optional switch to disable the LEDs). The kit also provides four spare‑fuse sockets and a full set of blade‑style fuses, all fitting beneath the stock fuse‑box cover. Installation involves removing the existing torpedo holders and dropping the board into the original slots, requiring no additional wiring.
Target Audience
Owners and restorers of classic BMW E12, E23, E24, and E28 vehicles who need a dependable, low‑maintenance electrical system.
Features
- Direct‑fit circuit board that replaces torpedo fuse holders while using existing fuse‑box slots
- Lower total resistance and stable contact pressure for more reliable power distribution
- Integrated LED status indicators (green for live, red for blown/missing) with a disable switch
- Four built‑in spare‑fuse sockets and a complete set of blade‑style fuses included
- Compatibility with a wide range of part numbers for E12, E23, E24, and E28 models
- Retains original fuse‑box cover appearance and layout