drgoodwrench

In Norman Garrett's Performance Handbook, he states the STOCK FPR will increase fuel rail pressure when it sees boost through its manifold line. Has anyone ever measured the pressure change possible from a stock unit?

I am trying to figure out how I am able to get 150HP out of stock 1.6 injectors while keeping my AFR at 12. Either my BSFC number is too high, or there is a bump in fuel pressure....
Thanks..

18psi

iTrader: (76)

if the stock fpr, much like the stock narrow band, can only do so much

drgoodwrench

True, but how much is that? I'm trying to go back through my Dyno data to see where I can squeeze more HP or torque out of the beast while staying within the proposed rules for the racing class (stock injectors, stock pump, stock FPR, stock wiring to the Fuel Pump, stock battery). If I had some good data on the fuel pressure increase, I'd have some idea how much more boost I could safely run before running out of fuel.
Yes I will be going back to the dyno, but I'd like to have a game plan with parameters in mind.
I could put a T in line and check the fuel pressure myself, but if the data already exists, while I am "bench racing" tonight, I can at least generate some numbers.
Anyone ever do this? If not, I'll post the pressures after the next dyno session, FWIW.

18psi

iTrader: (76)

I highly doubt you'll find any good answers on here about stock fuel pressure regulators, since no one runs them on a band aid setup and never tweaks with them with a standalone. just my .02

drgoodwrench

Figure you are right about that, but thought I'd ask anyway...

olderguy

iTrader: (19)

As I remember, the stock FPR will put out a maximum of 50psi fuel at -0- and will increase fuel pressure 1 psi for each pound of boost.

Something is amiss if you are getting 150 whp with an AFR of 12 and stock injectors with everything else stock.

Could be that you have a re-adjusted or faulty AFM and a faulty thermosenser that is making your ECU run very rich, but even that is a stretch in my book.

drgoodwrench

Thanks for the info.
I guess I failed to mention that the ONLY non stock engine/fuel item is a fully programmable ecu, so the flapper box is gone and we run off a MAP sensor.
Build pics can be found here:
https://www.miataturbo.net/forum/t24504/#post294267

https://www.miataturbo.net/forum/t24491/

https://www.miataturbo.net/forum/t25259/