Originally Posted by rosspf (Post 1562009)

Neat. Did you decide to do that due to the data in this thread?

Originally Posted by Wingman703 (Post 1562018)

Yes. I needed 2-300 extra RPM to avoid bouncing off the limiter for 3 seconds, or doing a split second awkward 3-4, 4-2 shift at a local track.
Saving $300 on valve stem seals that I wouldn't be able to take full advantage of allowed me to put that money to a damper, which will be protection through my entire rev range.

Originally Posted by RedRevolver (Post 1595965)

Not to bring back a thread from the dead, but I ended up buying the VS437 / 418737 springs from ITM engine components. These springs seem to be pretty readily available for the time being.
Ebay Listing I bought from: https://www.ebay.com/itm/Volvo-122-1...kAAOSwpuBZ2Wkf

They installed just fine and everything fits up good. Quite obviously stiffer than stock. My feeling is these are the same as the VS855 based on fitments listed for them. If the specs listed here for the VS855 springs are accurate I can take measurements and compare to this page here: https://www.thewrenchmonkey.com/prod...d-power/vs855/

Good news for some of you is that I'm a dumbass and lost two so I had to order an extra set and now have some extras if anyone wants them for testing with just let me know.

Originally Posted by TNTUBA (Post 1546007)

Valve spring pressure will not contribute to "parasitic loss" in a way which will cost you power. Equal and opposite reactions are taking place. For every valve working against spring pressure to open, one is working with spring pressure to close. Furthermore I have NEVER seen an engine (bossted or NA) make less power with stiffer springs(sure it would happen at ridiculous seat pressure...but in 20+ years of experience, I've never seen it happen), quite the opposite has happened. Controlling valve movement is paramount to making valves live, guides live and making the most power you can. As long as your lifter surface area, valve keepers and retainers can withstand the pressure (and ours can hold well over 100lbs of seat pressure and more than 300 over the nose) there is absolutely no downside (other than cost) to running the stiffest springs you can afford.

Springs are also a wear item. Like any other spring, they will lose pressure with use and the alloy used in the cheap Volvo springs will lose pressure at a more rapid rate than even the stock Miata parts.

I ran these springs for half a season in a Autocross motor, killed a set of valves and tested about 15% lower on the seat when they were puled out of the motor.

With Valve springs being such a highly important component for reliability and power, I would be using the absolute highest quality and highest pressure springs I could afford.