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SVT Shelby GT500
NSR Cams VS JDM Cams
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<blockquote data-quote="JimIII@jdm" data-source="post: 15231723" data-attributes="member: 10902"><p>Replacing your factory cams for ones with more lift/duration while reusing factory valve springs is going to create more risk of valve float and effect overall efficiency of the engine. I understand everyone wants a cheap and simple alternative for any upgrade but this is not the area to skimp. The factory valve springs NEW are about half the rated seat pressure of the PAC springs we include in our cam package. When you have 15+ psi of boost pressure pushing on the back of the valve the extra spring pressure is going to allow the valve to return to the seat with out issue. With the weaker stock springs and aftermarket cams the valves are going to open further and have more difficult time returning to the seat to close with what's known floating of the valves. When this happens your bringing heat into the engine and dumping boost out of the exhaust. </p><p></p><p>Whether or not you buy our cams or someone elses I would highly recommend replacing the springs for ones with higher seat pressure. Also 4v cam installs should be performed by a professional.</p></blockquote><p></p>
[QUOTE="JimIII@jdm, post: 15231723, member: 10902"] Replacing your factory cams for ones with more lift/duration while reusing factory valve springs is going to create more risk of valve float and effect overall efficiency of the engine. I understand everyone wants a cheap and simple alternative for any upgrade but this is not the area to skimp. The factory valve springs NEW are about half the rated seat pressure of the PAC springs we include in our cam package. When you have 15+ psi of boost pressure pushing on the back of the valve the extra spring pressure is going to allow the valve to return to the seat with out issue. With the weaker stock springs and aftermarket cams the valves are going to open further and have more difficult time returning to the seat to close with what's known floating of the valves. When this happens your bringing heat into the engine and dumping boost out of the exhaust. Whether or not you buy our cams or someone elses I would highly recommend replacing the springs for ones with higher seat pressure. Also 4v cam installs should be performed by a professional. [/QUOTE]
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NSR Cams VS JDM Cams
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