nose over at 6000 rpm not enough fuel??

[rawhawk@comcast]

I have been working on a nitrous set up when I use the 100hp jet the car noses over at 6000rpm in 2nd gear. I installed a adjustable fuel pressure regulator, when I first started the car to old fuel pressure regulator was still on the fuel rail. the new Ajustable FPR showed only 25 psi was the old regulator bad??? after I adjusted the new regulator to 50 psi the car ran like a bat out of hell. I tried the nitrous and had no problem through the full rpm run.
My question does anyone think that the old fuel pressure regulator was a bad one or was the new regulator just set at that pressure???
Thanks for the help
Rawhawk

[MidwestM3]

What was the new FPR set to? With the two regulators in series they could have been limiting the pressure more than just the stock one was. Also, if you are running a turbo and nitrous I would assume that you have a wideband O2 sensor? Did it show that you were running lean in the upper RPM band? If you don't have a WB O2, get one.