This Bourne HPP valve spring set is designed for N/A builds and will handle between 200-350 bhp (N/A). The spring set is designed for standard fitment using original platform shims and retainer setups. The valve spring diameter is the same as original Honda Type-r valve springs so you can upgrade the valve springs without changing the spring bases or retainers. A fantastic upgrade used to run most aftermarket camshafts with max lift 14mm or less. We also recommend this spring kit as a refresh option for customers with Type-r valve springs already but the engine has alot of mileage and/or the springs are getting soft. 

What is required to run the valve spring set? 

If you have a Type-r cylinder head you require no extra parts 

If you have a bare cylinder head or non Type-r cylinder head you will require-
* Valve spring set 
* Valve spring base set 
* Valve spring retainer set 

What is in our complete kit? 
* Bourne HPP valve spring set 
* Honda OEM NEW spring bases 
* Honda OEM NEW steel retainers 

Why do we use steel retainers in our kit and not titanium? 
Titanium retainers are much lighter than steel and in the valvetrain world there really isn’t a penalty for reducing the overall amount of weight in the system. In fact, less weight increases efficiency and allows the engine to rev higher without losing control of the valvetrain. Steel retainers are typically 40 percent heavier than their titanium counterparts, but that doesn’t mean they should be avoided for all engine builds.For endurance and strength, we stay with a steel retainer. we definitely prefer using a steel retainer when available for a street car and for track engines not exceeding 9,000 rpm.

What is a spring base? 
A spring base is the term used to describe the platform that the valve spring sits on. When you change from the non Type-r valve spring, the bases need to be changed as the new spring diameter is wider then the non Type-r spring.