Power Driven 3K/4K Governor Springs — 1994–1998 5.9L 12v Cummins (P7100)Governor springs are widely considered the best bang-for-buck first mod on a 12v Cummins. The stock P7100 injection pump is...
Governor springs are widely considered the best bang-for-buck first mod on a 12v Cummins. The stock P7100 injection pump is governed to cut fuel well before the engine reaches its potential — these springs raise that RPM ceiling, unlocking more power, sharper throttle response, and a noticeably different driving experience. One kit, one afternoon, immediate results.
Kit Includes
Full set of 3K/4K governor springs
Spring bases (retainers) included
3K or 4K — Which Do You Need?
3K (remove the center spring) — Raises the fuel cutoff to ~3,000 RPM. Safe for stock and mildly built engines. The right choice for most street and tow trucks. Better throttle response and power without pushing the engine beyond its limits.
4K (leave the center spring in) — Raises the fuel cutoff to ~4,000 RPM. More aggressive, best suited for built engines with supporting mods (upgraded valve springs, head studs, turbo). Not recommended for stock motors.
⚠️ We strongly recommend installing heavy-duty 60lb valve springs if you plan on revving to 3,250 RPM or higher. Without them, stock valve springs can float at higher RPM and cause engine damage.
*May not work for all builds due to other engine/vehicle modifications.
Frequently Asked Questions
What do governor springs do on a 12-valve Cummins?
They raise the RPM limit of the mechanical P7100 injection pump, allowing the engine to rev higher and produce more power. It’s one of the most cost-effective performance modifications available for a 12-valve Cummins.
Will governor springs hurt my engine?
On a stock engine, 4K springs can accelerate wear. 3K springs are generally safe for stock or mildly built motors. We strongly recommend installing heavy-duty 60lb valve springs if you plan on revving to 3,250 RPM or higher.
Do I need any special tools?
Basic hand tools and mechanical knowledge are sufficient. Installation is straightforward — watch the install video below. Our optional Governor Spring Adjustment Tool makes the job easier if you plan to do it more than once.
