[Fasterthanyou]

Originally Posted by JL8Jeff

From what I've read, the VRFPR will give a higher fuel pressure at max than any of the adjustable FPR so that's why it works better. Sounds like you guys it had it hooked up to the wrong vacuum source. But another restriction could be his fuel line. The factory fuel line is pretty small and can restrict the hp potential in the 450 hp + range which sounds about where he is.

It won't do that, it's actually the opposite. What it does is use the "set" fuel pressure at WOT and cranking (no manifold vacuum) and then when there's vacuum it will pull DOWN the fuel pressure. So let's say we making his AFPR vac ref. Hook up the vac line and all of a sudden instead of the 12psi he's running now he'll only have 8psi. Then when he puts pedal to floor it'll go up to 12psi. The only reason to need a VRAFPR on a TBI motor is if you're running 450+hp with 2 injectors and having trouble getting it to idle (pulse widths are too small). Other than that, whoever told you it was different needs to get his facts in order because he's not a very good edjumicator
Also, we he doesn't have a VRFPR so we can't hook it up wrong. There is no vac ref with decent TBI regulators. The ones that are were patch fixes and were crap, I'd never use one again.
Yes, the fuel line size does become a factor. We'll be pushing it's limits with this motor but I've told Matt that from the beginning. I honestly think the best route to tuning this beast is to get a carb on it and tune that first. That way you know the power potential and with TBI, just try and match it. It's a great way of finding if you're fuel limited.