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-   -   Fuel pressure regulator 2001 FPR question (https://www.miataturbo.net/general-miata-chat-9/fuel-pressure-regulator-2001-fpr-question-103119/)

Icedawg 06-06-2020 10:30 AM

Fuel pressure regulator 2001 FPR question
 
I have not dealt with a non-vacuum referenced FPR before. I am curious how the system is made to work on the NB2, and why such a simple method to compensate for pressure rise in the intake manifold would be abandoned.
I will be putting a turbo on a 2001 Miata, and I am curious how the rising pressure is compensated for. I assume the MS3PNP ECU must do the job instead, taking MAP and calculating how that will affect flow through the injectors? But since the stock ecu uses MAF, I don't see how the stock system would do it.
My brief search attempt gained a few tidbits, but not enough to satisfy my curiosity. Hopefully someone will be willing to fill me in.


DNMakinson 06-06-2020 11:16 AM

Yes. Read the Set-up Manual and the Lite TS Manual for your ECU. It will have the fueling equation. Choose "Include AFR". Not that that makes things work, it is just the best choice and should be made before tuning the VE table.

DNM

Icedawg 06-07-2020 11:03 AM

Thanks DNM.
The related topics list came up with more informative threads than I managed with my search.
In this one, dated around 2012
adjustable fpr vs oem
both Sixshooter and Leafy say a vacuum referenced fpr is the way to go, especially for boosted applications.

Just yesterday I was given a JDM 1999 fuel rail, which uses a return fuel line, and a vacuum referenced FPR.
Would it be a good idea to swap over to this as I get the build underway on the 2001? Obviously there would be some work to do on the fuel system back near the tank, and a return line would be needed.

DNMakinson 06-07-2020 12:51 PM

I did convert to referenced. Not at all sure if worth the effort, especially if you buy Flow Force matched Injectors, but also unless you are going more than 15 psi.

I used a fuel supply line from another NB as the return line.

See my build thread. My car is an NB1, I understand some things are different at the tank for NB2.
DNM


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