Nissan GT-R Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
8,155 Posts
Discussion Starter · #1 ·
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?

Thanks,
 

·
Premium Member
Joined
·
12,530 Posts
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?

Thanks,
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.
 

·
Registered
Joined
·
8,155 Posts
Discussion Starter · #6 ·
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.
 

·
Registered
Joined
·
7,513 Posts
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.
 

·
Registered
Joined
·
8,155 Posts
Discussion Starter · #9 ·
You won't have enough fuel at 42 psi at idle on ID1000 on E85. The only reason I bump up fuel pressure is to have enough fuel for ID1000 on E85 that was a year ago. Now I have changed to 1100 cc injectors, I bump it down to 52 psi.

If when I upgrade the turbos, I will bump it to 40 psi to get a better idle and like you say, more head room due to the fuel pumps characteristics.

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.
 
1 - 9 of 9 Posts
Top