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Discussion Starter #1
just out of curiousity... how much RPMs would one have to turn on their engine to be forced to upgrade their valve springs?? i often wonder how much RPMs the stock valve springs can handle... or are the RPMs arent what makes one upgrade the valve springs? ...
 

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Thats a good question, I believe I read somewhere that 7400-7500 was where most people would change them. I have run mine to 7200 (limited by FSWerks tune) or so with no problems.
Most people have to change them out do to the cams they are running, too much lift combined with high RPM that you get coil bind and valve float.
 

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I have my limiter set to 7200 just because I dont make any power higher up.


BTW you can change the limiter with the handheld tuner. I think up to like 7600 or 7800 but DO NOT DO IT!!
 

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Discussion Starter #4
haha i wouldnt dare run it up that up high on a stock valvetrain... that'd be more than valve float issues! the bottom end doesnt like anything above 7200 right? i read on a 2.3 build that guy said his stock crank didnt like north of 7200rpms.
 

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Valves will almost always float before a crank has issues. However yes once you get into those speeds (and once the valvetrain has been upgraded) a stock crank can present issues.
 

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At high rpm the stock crank is weak, but if you keep it below 7200 it will hold like 300-400 something whp.
 

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Both. It comes down to a matter of crank balancing, harmonics, and how well the crank was actually made in terms of internal structure and metallurgy.
 
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