ive seen the poll that was done earlier and seemed like most people agreed on atleast 20k is a good life on a valve spring. only thing is what kind of mods/cam was being run on the valve springs. for me i have a mild cam .600 lift headers,lid, and exhaust. would 20k be a fair estimate on what kind of life i could get out of some 918's?

 

A high quality springs like Patriots dual or a PAC-1518 beehive should last 50k plus easy with that set-up.

So many things can effect a springs life. RPM and how long it sees that RPM, overall valvetrain dynamics, stress range (lift and how close it's run to coil bind), etc...

 

I have the same question with 14k miles on a .600 lift cam with 918 springs. Last thing I need is to blow my motor for a few extra ponies.