- 2002-2005 WRX
- 2006-2007 WRX
- 2008-2014 WRX
- 2004-2007 STi
- 2008-2014 STi
- 2015-2021 STi
- 2004-2008 Forester XT
- 2009-2013 Forester XT
- Brand: Tomei
- Manufacturer's Part Number: TA304A-SB01A
- Manufacturer's Warranty: 1 Year Warranty
- Superseded From: 163057
- Condition: New Product
High quality designed springs is required to transfer the exact movement of the camshaft to the valves at high engine speeds on high performance engines. The TOMEI products are always engineered with precision in mind to suit the user's needs. So with this in mind careful choices in material selection is made with surface coating and other technologies. Then the pre-production products are put through an extensive testing program for checking durability, quality and performance. We spend time and money to help you save your valuable time and money.
Reliability in high RPM, and improvement in an initial response
High durability against metal fatigue
High durability against the shocks from jump and bounce
High durability against surging
High sag resistance
Multi Coil Unequal Pitch Springs
By combining several steps of spring rates into the one spring and vibration frequency becomes amazingly high. This greatly minimizes resonance and the chances of surging.
Advanced Oil Tempered Chromium-silicone Alloy Steel Core
Oil tempered chromium-silicone alloy steel wire is used which is considered to be the best material for springs for performance applications and evolved it even further. Combined with a new optimized design, not only did we make it tougher, we also succeeded in suppressing valve jumps or bounce even when raising the engines speeds RPM limit.
The surface treatment method for making nitrogen permeates the spring and gives it large surface compression repulsion. This method was chosen to raise the fatigue limit to suit the demands or running high lift camshafts. The dangers of spring failure is greatly reduced with the 1.5 times increase in the springs fatigue limit with the combined use of Oil tempered chromium-silicone alloy steel wire and Nitriding. This is how our valve springs are suitable for use on extreme engine speed conditions of super-high revs exceeding 10,000 RPM which had not been previously possible with high lift camshafts.
A process that strikes many small steel balls onto the surface of the spring at high speeds is made to enhance the surface of the spring to raise its fatigue limit. Although it has been carried out earlier during the manufacturing process.
The process that is adding higher loads beyond the actual limits to the highly heated spring. This will modify its shape and keep it permanently fixed. We succeeded in securing the highest performance over a long period of time while preventing sagging.
Using highly durable oval wire allows the valve springs to compress even further whilst still retaining sufficient force. Compatible with many high lift camshafts, these springs provide reliable performance even under load at higher RPMs.
Oval wire valve springs feature greater compression than regular valve springs, allowing them to work with a wider range of 'lift' settings. This makes them compatible with both stock AND aftermarket high lift camshafts.
Surging: The Phenomenon which material of the valve spring resonance and causes the spring itself to vibrate violently.
Jump: The Phenomenon that the valve rallies to the cam surface instead of settled back. It happens when the valve cannot follow the camshaft rotation and lifted irregularly.
Bounce: The Phenomenon that the valve is bouncing repeatedly from valve seat other than sticking to it when it is closing.
Fatigue: Breakage that occurs during the repeat operation of the spring. (The larger lift, the more possibilities to get fatigued)
Sag: The Phenomenon in which the load (free play) of a spring decreases while in use. It is related to the maximum stress under operation and use time.
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