Forge recirculation valve
08-02-2010, 01:59 PM
#1
Forge recirculation valve
Hi all,
I installed a Forge recirculation valve but and am not sure as how to install it correctly. I don't think I found the answers to my questions in the archives.
I currently run 15psi. I therefore use the yellow spring supplied wih the valve, recommended for this boost pressure.
1) Installed the factory way, the valve seems to perform the same way as the factory valve as I reach the wastegate spring stiffness (a shade below 15psi), however I can hear it spluttering once peak boost is reached, while the factory valve doesn't splutter. Is this normal?
2) Installed the other way around, with the same spring, the forge splutters even before reaching peak boost which by then will be no more than 14psi.
Is this normal?
Which way should I install it and should it splutter under boost before closing the throttle?
Thanks in advance.
I installed a Forge recirculation valve but and am not sure as how to install it correctly. I don't think I found the answers to my questions in the archives.
I currently run 15psi. I therefore use the yellow spring supplied wih the valve, recommended for this boost pressure.
1) Installed the factory way, the valve seems to perform the same way as the factory valve as I reach the wastegate spring stiffness (a shade below 15psi), however I can hear it spluttering once peak boost is reached, while the factory valve doesn't splutter. Is this normal?
2) Installed the other way around, with the same spring, the forge splutters even before reaching peak boost which by then will be no more than 14psi.
Is this normal?
Which way should I install it and should it splutter under boost before closing the throttle?
Thanks in advance.
08-02-2010, 02:30 PM
#3
Nordschleife Master
You want to install it so the piston is being forced down (closed) by the boost pressure from the charge pipe, so method #1 is correct. By doing it in method #2, the boost pressure is pushing on the piston making it open sooner.
It sounds like you need to use a slightly stiffer spring or add washers to effectively stiffen your spring. I am pretty sure Forge sells spacers (or you can just use washers) so you can effectively stiffen the spring, allowing you to get a 'spring rate' inbetween 2 springs..basically fine tuning it. Too light a spring and you will experience the valve opening too soon causing the 'sputtering' at full boost, too stiff and you will get compressor surge when you lift.
It sounds like you need to use a slightly stiffer spring or add washers to effectively stiffen your spring. I am pretty sure Forge sells spacers (or you can just use washers) so you can effectively stiffen the spring, allowing you to get a 'spring rate' inbetween 2 springs..basically fine tuning it. Too light a spring and you will experience the valve opening too soon causing the 'sputtering' at full boost, too stiff and you will get compressor surge when you lift.
08-02-2010, 02:40 PM
#4
Thanks Jon, I actually purchased the spring kit along with the valve and already tried method #1 with the softest spring and with one washer, by then I think I reached a bit more than 15psi, which is a bit more than what the wastegate spring allows.
Is this good or bad? I take it I shouldn't let the valve build more boost than what the wastegate spring allows?
Is this good or bad? I take it I shouldn't let the valve build more boost than what the wastegate spring allows?
08-02-2010, 11:49 PM
#5
Rennlist Member
I don't get what you mean by "sputtering"
When approaching full boost the bypass valve shouldn't open at all, regardless of what spring; the boost/vacuum line from the intake manifold cancels out the boost from the charge pipe in front of the throttle body.
The only time a weaker spring is an issue is when you're accelerating at part throttle and higher pressure from the turbo discharge is banging up against the partially closed throttle plate. You could get a jerked boost rise at that point and maybe there's a noise accompanied with that.
Also, I've got the same valve, have taken it apart, and the area where the boost pushes on forces it OPEN from the charge pipe and is pretty much the same no-matter which way you install it.
When approaching full boost the bypass valve shouldn't open at all, regardless of what spring; the boost/vacuum line from the intake manifold cancels out the boost from the charge pipe in front of the throttle body.
The only time a weaker spring is an issue is when you're accelerating at part throttle and higher pressure from the turbo discharge is banging up against the partially closed throttle plate. You could get a jerked boost rise at that point and maybe there's a noise accompanied with that.
Also, I've got the same valve, have taken it apart, and the area where the boost pushes on forces it OPEN from the charge pipe and is pretty much the same no-matter which way you install it.
