BMW M47 and M47N engines have most weakest springs what we have measured from stock passanger car diesels.
This causes these engines to stop power production and get smokey after ~4000rpm, issue gets worse with more boost and exhaust manifold pressure.
These springs are "bolt-on" and will handle the additional boost and wont start to float untill well beyond 5000rpm.
- Seat pressure ~20kg compared to the stock ~15.5kg. (29% difference)
- Open pressure at 8mm lift is ~42kg compared to the stock pressure of ~25kg. (70% difference)
- Recommended maximum lift 11mm.
