With engine running, this seems correct. However, I usually would try for about 52psi with vaccum line disconnected. When you connect the line, the pressure should drop to about 42-43psi. Sometimes, aftermarket regulators require some preload on them before they start working so you might have to run a bit more pressure if this is the case. With the line connected, a strong blip of the throttle should result in a quick spike in pressure on the gauge. This means the regulator is working properly and your fuel pumps are installed correctly.I am a little confused. I read GTR fuel pressure is at 52 psi. Is that at idle or no vaccum? I am adjusting my FPR and I have it set 64 psi no vaccum or 52 psi with vacuum line hookup. Is this correct for HKS FPR?
I know factory is set @ 52, probably for better atomization and fuel efficiency, but why not run at a lower pressure, like 42 psi @ idle? You'll have way more headroom for boosting high.Thanks guys. I tried 52 psi with vacuum line with hks fpr and my air/fuel look just like stock. I bumped it to 60 psi idle with vacuum and it gives me about 10% head room in injector duty cycle which is what I want. I use the AAM adapter and gauge. One can put it on without removing anything which I didn't know, otherwise I would have measured stock fpr pressure.
I know factory is set @ 52, probably for better atomization and fuel efficiency, but why not run at a lower pressure, like 42 psi @ idle? You'll have way more headroom for boosting high.