Drakk0r

Ok, so I've discovered my fuel pressure regulator has gone bad. I'm gonna start installing a turbo and a fuel system to support it as soon as my tax return check comes in. Now... Should I get a stock replacement FPR? Or is the SX adjustable a better choice considering my future plans?

RETed

Stock replacement is easier...
The SX FPR *need* AN fittings and lines, and you're looking at another $500 worth of stuff to do this correctly...

http://fc3s-pro.com/TECH/MODS/FUEL/fpr.htm



-Ted

kabooski

Ted's FPR layout is OK
But this is the BEST way for a FC
and uses the least amount of B lines therefore reducing the cost
and you *can* mount it just like that on the stock rail

RETed

"Best" is relative.
The parallel fuel rail system is superior over the series system in terms of fuel delivery.&nbsp The FPR is a two-input design, so why waste the other port?&nbsp You have much superior fuel delivery with a parallel versus series - go think about it before you respond.

The ONLY advantage of running it series like the stock fuel fuel rail system is decreased cost.&nbsp If I were to invest in this much upgrades, I would at least want to take advantage of the superior fuel delivery design of the parallel fuel rail system myself...



-Ted

Drakk0r

If I keep the stock FPR and run a more powerful fuel pump, wont that increase the fuel line pressure? Or can it regulate any amount of pressure from one side (input)to the other (output)?

Note: My thinking is that the FPR is designed to regulate a certain pressure rage from the input side, to a fixed maximum pressure on the output side. So wouldnt increasing the line pressure on the in side also increase output pressure as well? Wont that cause more fuel to flow through the injectors? Please excuse my lack of knowledge of fuel systems.

RETed

Yes, that is generally true - a significant increase in fuel capacity via an upgrade fuel pump will generally increase fuel rail pressure.


Nope, you've got is exactly right.&nbsp Running from an NA to a Turbo II stock pump does very little in increasing fuel rail pressure, but running from a stock Turbo II fuel pump to a Walbro 255lph fuel pump shows around a 5psi gain.&nbsp For reference, the stock Turbo II fuel pump runs about 185lph...



-Ted

BLUE TII

iTrader: (9)

Great luck! I was about to start a thread about this and I saw this one. I am planning on purchasing the SX dual outlet pressure reg. (you just use the pressure gauge outlet for a fuel line right?) and run parallel lines to primary and secondary. I have an 89+ primary rail w/ pulsation dampner.
Should I put a "crossover" between the two lines so the secondaries are dampned as well? Or should I put in a second PD for secondaries? I am worried huge secondaries will cause a big line fluctuation that won't be dampned...Ian.

BLUE TII

iTrader: (9)

OK, just read that the SX FPR provides pulsation dampening accordidng to its literature.

Drakk0r

Ok, sorry to keep asking dumb questions.. But since we've now established that the fuel pump I plan to purchase (255lph Walbro) will increase fuel line pressures. My next question is; Is there any harm in running that much more fuel pressure through a stock replacement FPR, through stock fuel rails to feed the 680cc/min injectors I plan to install? The only thing I can think of, will be that more fuel will flow through the injectors, so I'll have to tune the fuel down some (relatively) with my HKS AFR.

Thanks for all the good info. I really appriciate it

RETed

Running slightly rich just supresses some power - nothing dangerous...
With the HKS AFR, you can tune the fuel delivery down a bit to get back the lost power...



-Ted

Drakk0r

Damn your quick to respond.. Thats what I was thinking, but I like to have the confidence of knowing exactly what to expect.. Thanks again for the info

VT GT

Since we are on the topic. AFter installing a FD pump on my 90 T2 last weekend it now has to crank awhile before starting up like it is flooded a little bit because of the extra fuel rail pressure. IS this because my stock fpr can't regulate that pressure or is going bad? What would be a way to fix this other than a fuel cutoff switch. The car used to start perfect everytime at the first turn of the key.

-Jason

btw. I am on my friends computer

HAILERS

Note: My thinking is that the FPR is designed to regulate a certain pressure rage from the input side, to a fixed maximum pressure on the output side. So wouldnt increasing the line pressure on the in side also increase output pressure as well? Wont that cause more fuel to flow through the injectors? Please excuse my lack of knowledge of fuel systems. DRAKKOR........Its possible I'm a functional illiterate, but if you look at the attached jpg, and then read your words at the top of this post, I think you might want to readjust the way you think about the fuel pressure regulator. The way I see it, is that the pump puts out 70-90 psi but the regulator dumps anything over 37 psi(if you have the vac hose off the regulator at idle) back into the tank. I'm saying the fuel pressure regulator comes after the fuel injectors. Its regulating the pressure to 37psi on the fuel line b/t the pump and the fuel pressure regulator, its not regulating the pressure AFTER the fuel pressure regulator. Then again I could be reading you post wrong. If so, sorry 'bout that. JPG ATTACHED:

Cameljoe

Ted, can you use the stock fuel rails (retap the rails to use the new fittings) or do you need to get a custom rail made?

RETed

The Zenki stock fuel rails are good up to 500hp...
All the major AN makers offer metric to AN adapters to keep the stock Zenki fuel rails; sorry Kouki owners, but your stamped steel fuel rails need to be welded or swapped out...



-Ted

fcturbo2

Im gonna do the parallel fuel system set-up for my 87TII project. If you are using all 3 ports of the SX FPR what do you do if you are planning on installing a fuel pressure gauge???

RETed

Damn, 2 months old back from the grave!
There are 1/8"NPT adapter ports available if you're using AN hardware.
Try and get an FPR that has a built in 1/8"NPT port - this makes it a LOT easier.

-Ted