Alright I just ordered a TO4R, manifold, and wastegate. I have already upgraded my whole fuel system a few months back (1680 sec. inj., nippondenso fuel pump rx7store sells, sx fpr) Now my question is will this pump be enough for my new turbo? If not can i just add my stock pump to the mix (and how would I do this) or do I need to get another pump of the same flow?
M-P

 

The turbo is not the factor. How much boost you run and your AFR levels determine your fuel requirements.
If your ND pump is like the one RP sells, than it is good for about 500hp with good wiring and hose.


When you start tunning you car and get above 12PSI,
watch you fuel pressure. As long as the pressure meets the Mazda specs, you are OK.

Under Boost Fuel Pressure = 38 + boost pressure in lbs/inch. For 12PSI, your FP should be about 50psi.
For 14psi boost, 52psi FP.

This is based on a 1to1 ratio FPR.

 

Thanks for the Fuel Pressure info. I understand that it is the boost levels to the turbo, but I also know that the boost level of a certain turbo obviously requires more fuel. I am gonna run it at 15psi.

Now can someone answer my other question: Can you run the stock fuel pump along with the upgraded one? or do they have to be equal pump?

M-P

 

I have a Nippo pump with the TO4S running 16lbs and was hitting high inj duty cycles. You should go with a dual pump setup to be safe.

 

Here's my setup

T04S
RX-7 store upgraded ND pump
36 psi fuel pressure at 0 manifold pressure
1:1 boost compensating fuel pressure reg
550/1600 injectors

At 15 PSI, I hit around 90% duty cycles max.
My fuel pressure does not drop off (I have a gauge)

To run more boost, I will need to either increase the fuel pressure or add more injectors. If either of those two actions exceeds the flow of the pump, then it's time for a new pump.

 

I had the same pump and ran out of fuel over about 15 psi. That pump is good for about 400rwhp with conservative tuning.

To answer your question, Yes you can run both pumps, however, its often recommended against because if one fails you still have fuel, but not near enough, so you have an ultra lean condition which means bye bye motor.
Whereas with one big pump if it fails you have no fuel at all, so you are much safer.
How often do pumps fail - not very often. but why not just sell the nippondenso and buy a bigger one for a few extra bucks.

my 2 cents

-Rob

EDIT: I didn't see that you had the SX FPR. I did not have a RRFPR, you should be ok with that pump and an SX FPR i think, but i don't have any experience here. Probably good for limits of pump gas and map sensor (450ish rwhp)