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Revs, PSI and cam profile are the three biggest/ if the only factors when considering valve spring upgrade

I don't see how power makes a difference

Generally Jap and standard cams have a pussy profile so a stronger spring is less required

I realise that......but FWIW, most people intent on running 20 psi put on a turbo big enough to do 20 psi at the best flow/most response they can get. People wanting to make more power will put on a turbo able to do 30 psi at the best flow/most response they can get at that level. etc. Doesn't matter if it's a HG highflow, HG replacement, Garret GT/X, Holset, whatever. At any given power level, the most appropriate current turbos (let's ignore old tech turbos) from different sources are all approximately the same thing. If you stray off that line then you're choosing something that is either being run below its best boost for the flow or below its best flow for the boost.

Edited by GTSBoy

Next we will be dragging out compressor maps to see where our valves will float.

The point is, power itself doesn't influence where or when this issue will arise.

Boost, revs and ramp rate of the cams are it. If the engine makes 200 hp at 15 psi at 6500 rpm and it floats, why would it float earlier with 600 hp at 15 psi at 6500 rpm?

  • 6 months later...
  • 1 year later...
7 hours ago, CHRIS MW33 said:

hey any updates on this topic? how have the Performance Valve Springs held up over time for the rb25det neo? also any other spring manufactures other than ferrea trusted for the NEO?

Mine have been in for 6-7 years with the car doing around 15-20 track days a year on top of many KMs of street driving before it was made into a dedicated track car.

Never missed a beat with the Performance Valve Springs! Good gear :thumbsup:

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