2gNT fuel pressure regulator - trying to tune down

[siueclipse]

I need to change my fuel pressure regulator. However, Ive been reading a lot about the ratio that comes with them. Could someone please in lamens terms explain what ratio I should go with? I want to run 15psi of boost which is going to call for around 85psi of fuel pressure. On the track, Im going to want to run 24lbs of boost on race gas.. Im not sure what the fuel pressure would be at that point, but im sure it would be lower.

Sorry im confused.

James

 

[Mike 99GSX]

Your FP should raise 1 psi for every psi of boost that you build. So if you have your base set at 50 PSI with the vaccuum hose disconnected, you should hit 65 psi FP when you build 15 pounds of boost.

 

[siueclipse]

ok makes sense.

thanx

 

[kpt4321]

Not necessarily.

He has a 2g NT with some sort of turbo kit, but he decided we had to figure that out on our own. I guess we're psychic.

Give us some more details about your setup. What size injectors are you running? What kind of FPR do you have now? What other tuning tools do you have?

Then we can help.

The ratio is simply how much the fuel pressure rises for each psi of boost increase in the manifold. If you have a 50 psi base pressure and a 5:1 FPR, at 1 psi in the manifold you will have 55 psi of fuel pressure. With that same base pressure, and a 12:1 FPR, at 1 psi you will have 62 psi of fuel pressure.

We turbo guys use 1:1 FPRs, that simply offest the boost pressure by increasing the fuel pressure with it. However, you might need more than that if you're using fuel pressure to compensate for smaller injectors.

....Kyle T.
93 TSi AWD "TURBO4"
14b - 12.8 @ 108