Difference in Valve Springs

[07TGGT]

I just purchased Comp 127300 Cams and have been looking at valve springs. They list 2 valve springs that you can use with the cams on Comp's website.
Now my question(s) is which would be better? And does O.D and I.D stand for outside diameter and inside diameter?
26125-24's
http://www.compperformancegroupstor..._Code=CC&Product_Code=26125-24&Category_Code=

26113-24's
http://www.compperformancegroupstor..._Code=CC&Product_Code=26113-24&Category_Code==

So spend the extra $30 and get the 26125's?

If someone could also explain seat load, open load and coil bind I would appriciate it.

 

[Cali HP Addict]

If it were me I would choose the lighter seat pressure springs. They will work perfectly with those cams up to and probably past 7000rpm. The higher seat pressure makes it harder on the VCT.

 

[07TGGT]

What exactly is seat pressure and how does it affect the VCT?

 

[Cali HP Addict]

It is a measurement of how "stiff" the spring is at the installed height while the valve is closed or seated. The stiffer the spring, the harder it is to turn the cam while the valve is ramping up the lobe. The more radical the cam, the more spring pressure required to keep the valve from floating. Same goes for higher rpm or lots of boost pushing against a seated valve. The idea is to have a spring that is stiff enough to follow your cam reliably in your desired operating rpm. If you go stiffer than that you won't gain anything and you will just make things harder on your VCT and valve train.

 

[ArtQ]

Good valve spring info here........


Good VCT info here.....

The 26113's worked fine with the 127300 cams, I am currently using the same spring with the 127500 cams with no issues.

 

[07TGGT]

Awesome, thanks for the info