View Full Version : Boost Reference source and FPR Question...

11-29-2006, 03:34 PM
I am wondering if the output from the turbo compressor vacuum fitting would be higher than the one on the intake manifold that goes to the FPR. I am assuming it would be if there is any sort of pressure drop across the stock Turbo to Intercooler tubing as well as the intercooler itself.

This leads me to another question: Would it be beneficial to plumb the FPR vacuum line directly to the turbo compressor outlet to increase the pressure seen by the FPR, and consequently, increase the fuel pressure?

I know the FPR is a common source for boost gauge plumbing (that's where I have mine), but I am hoping that there may be someone out there that has done this or knows the relative difference between the two sources.

Also - does the compressor fitting produce vacuum at all? Obviously the intake manifold fitting has both pressure AND vacuum. Is vacuum needed by the FPR or only positive pressure?


11-29-2006, 05:01 PM
you can't run this for the fpr. it will not see manifold vacuum. it may see some sort of port vacuum if only for a second but no, you can't use that. as far as using your fpr line for your boost gauge, i don't think that's the best idea. I would give your fpr the purest signal possible. It probably doesn't make too much difference, just may have better response time if it has lower volume (fewer vacuum lines). but no, don't use your turbo for fpr.

11-30-2006, 05:55 AM
Thanks for the info. Any other opinions out there? Or is this the answer? Can anyone explain how the FPR uses vacuum AND positive pressure to regulate fuel? Any links?