The main considerations are the sodium filled valves ultimately aren't as strong as the solid stemmed counterparts, but that becomes a concern mostly with high rpm and stiff seat pressures. The aftermarket sodium filled valves will flow better than the OEM parts, which again, becomes a factor where such things are at the top of the priority list.

 

The SuperTech sodium-filled valves are only available in +1mm, which you wouldn't need unless you're making a boat-load of power.

The OEM intake valves you could go bigger on, either +.5 or +1 mm.

FYI, I have SuperTech inconel exhaust valves on my car and the nitrided intake valves.

 

Thanks a lot for the explanation, and to answr no, I am not making a lot of power, 320HP atw low boost and 382HP ath high-boost, so I will stay with OEM valves

Now (just for the learning experience), the part I think I am confused is, when they say +1mm or +5mm, that means the valve has +1/+5mm more diameter that can be machined? Or it is just a valve that will open up the ports? to whatever + mm it has?

Still trying to understand that part. Thanks for your advice, very much appreciated for everyone

 

The larger sizes refer to the diameter of the valve face. Theoretically, larger valves allow for more airflow where that becomes restrictive. In this instance, the larger size is irrelevant, as the OE ports do not flow more air when fitted with larger valves.

 

Ted, my priority is durability, so if I am learning correctly here, staying with OEM valves is better for me because, I won't see that harsh racing constant high RPM as to require solid stem valves, and I can afford as well to stay with sodium-filled because the temperature effect also impacts durability positively. I do track-day my car, but again, that is not rallying-type racing.

 

Ok, I think it is clear now, can't thank you enough for the education!