I was expecting my Forge DVs to be in bad condition as I have not serviced them for years (not sure how many
), but full credit to Forge, they seemed to be as good as last time I serviced them. However in saying that, it made clear the difference between the R1s and the Forge piston valves: In order to seal the piston valves there are the two o-rings and the high-temperature grease. As a result you can definitely feel the friction as the piston moves. In constrast I could feel no friction in the R1s.Hardly a scientific test, but the springs in the R1s feel to have very similar tension as the blue springs (standard are green) I have in the Forge valves. Again, this gives me confidence for their use on a higher boost engine.
So what about performance on the road? Well I wasn't actually expecting much since my Forge valves seemed to be in a good state. As I think I mentioned earlier, I have been feeling that my car was experiencing some hesitancy, plus the peak boost seemed down. So I was ready to believe that this must be due to something else. But it is now clear that the DVs must have been at least partly responsible. Although I need a few more days/weeks to really experience any improvement that the R1s give, I can already report a difference. The car is definitely back to the peak boost I had before, and it also feels more torquey. I can only assume that despite appearances, but Forge valves must have been sticking.
So I have to agree with the others and recommend the APR R1s. I am not going to be negative about the Forge valves, because for years they have been a good valve to use. However it seems that APR have put the effort in to produce something better. Maybe Forge will design something new?
Of course this is all on the assumption that APR's claims about the R1's reliablility are true. Only time will tell...
P.S. I have not noticed ANY sort of noise from my R1s!