93FD3S

FD running large street port with to4s turbo with 850cc primary and 1300cc sec. Using Walbro 255lph pump and plan on running 18#s max. Should I upgrade to 1600cc sec with fuel rail and adjustable fuel regulator? thanks...Tony

pp13bnos

iTrader: (1)

I'm making 400+rwhp on the stock regulator. I'm running a Groundzero fuel pump, 850/1300 setup. At 16lbs of boost, the regulator was still doing its job well. CJ

Icemastr

iTrader: (2)

I believe you need an adjustable FPR with different injectors, i.e. 1600cc injectors. The 1300CC injectors are just stock injectors bored to 1300.

Ranzo

I don't think it is a matter of need it is just a choice. Some fuel rails, if you ever change yours, don't have the regulator built in. That would require a FPR being purchased.

If you are at max duty cylce on your injectors and need some more fuel to keep the required AFR then an adjustable FPR might be a good option, if you pump can handle the increased pressure.

Outside of that I really don't see a need to buy a aftermarket regulator.

93FD3S

Thanks for the input guys. Guess I'll run the stock fuel rail with the 1300cc injectors for now and see what A/F I get. Hopefully I won't have any problems using the stock fuel pressure regulator as well. Any other help would be great. thanks..Tony

93FD3S

Anyone else have any input? thanks..Tony

Snook

iTrader: (12)

Im very interested as well. I now have 850s and 1300s. I was getting 84% duty cycle at around 390rwhp with just 1200s and stock fpr. I wasnt planning on buying a fpr and thats the reason I didnt get 1600s. I dont want to deal with new lines, regulator, rail, and wiring of injectors. Im planning for 450-500rwhp. Whatever the injectors can pump out. Has anyone gone that high with this setup? Any other forseable problems?

maxcooper

If you want to stay with 5/16" rubber fuel lines, I found some 5/16" hose barb to AN6 adapters from PegasusAutoRacing.com that work pretty well. They are available as straight and 90 degree fittings, and are useful for connecting the stock return lines to an aftermarket FPR. That is what I am using on my car.

I have been running the stock FPR for a while with no problems up in the high 300 RWHP (maybe low 400s since I bumped my boost up) range. It seems to work fine. I have heard rumors that it is unreliable at high levels of fuel flow, but I am not sure if I believe it. I haven't read about any failures. Still, an aftermarket regulator is nice for changing your base pressure. I have been running both the stock FPR and the aftermarket one for a little while (whichever wants higher pressure "wins"), but I am removing the stock one now. I have been meaning to remove the stock one for a while, but just finally got around to it now.

-Max

fc1jz

Are you going to remove the secondary regulator?? Or are you going to remove the one on the primary rail as well.
I just put in an aeromotive fpr with my secondary rail and 1680cc injectors. I didn't remove the regulator on my primary rail though.
I need to take some damn pictures and post them up.

Snook

iTrader: (12)

there is no primary regulator is there? I think you might be talking about the fuel pulsation dampner. I could be wrong

93FD3S

Yeah my target rwhp is 425 so I'm hoping by using the stock FPR will be ok. So has anyone removed the fuel pulsation damper or just left it on when using 850 primary and 1300 secondary?

maxcooper

The thing that looks like an FPR on the primary rail is a fuel pulsation dampener (FPD), not a pressure regulator. I am going to remove the stock FPR from the secondary rail, and I have a new FPD for the primary rail.

-Max

Snook

iTrader: (12)

Max very helpful as usual!! Can you please tell me the material that the stock fuel rail is made of if you know? I want to polish mine but it appears to have the same coating as a few other parts in the engine bay which I know are mild steal because they have rusted after polishing.

And also since im pushing the stock fpr to crazy hp #s is there any way that ill know if something is failing while tuning? im going to have a tuner do it maybe kan how can we tell if something is going wrong? fuel pressure guage the only way?

maxcooper

The fuel rails are both aluminum. I am not sure if there is any kind of coating on them or not. I am looking at one right now, and they are kind of nasty looking -- very dirty or perhaps they do have some kind of coating. Perhaps a wire brush followed by some paint would be an easier way to make them pretty.

A fuel pressure gauge you can read from the driver's seat under boost is probably the best way to keep an eye on the FPR. You will need a gauge with an electronic sender (or a mechanical gauge with an isolator) so that you don't run a fuel line into the passenger cabin. Of course you can just run a mechanical gauge (with no isolator), but it isn't very safe and you might fail tech inspections if they notice it. Verdict: don't run fuel lines into the passenger cabin.

-Max

twokrx7

iTrader: (1)

Biggest issue I see with the stock setup is running the rails in series. I found a lot of pressure drop from the primary to the secondary rail. An adjustable FPR will allow one to crank up the base pressure to get a decent secondary fuel rail pressure without having to replumb the entire system. Probably nets better fuel spray/atomization on the primaries but its just a guess.

This will greatly increase fuel flow on the secondaries (1300s or 1680s), but, you will need a strong pump to maintain fuel flow at these higher pressures. Suggest a boost-a-pump or at least a rewire of the intank pump.

Rewiring my intank apexi pump netted me another 1.5-2 volts and it flows a river of fuel now. I believe this pump (rx7 store) could support 600 hp with a boost-a-pump upping the voltage even more.

Snook

iTrader: (12)

Max polishing the rail is easy maybe a 20 minute job. I dont remember how visible it is or how much you can see the inside of the lim hmmm?

twokrx7 can you expain how to rewire the fuel pump for max performance? Mine is a huge boshe I dont know what hp its good to but I should take it out and check.

bond007

In short:
Wire fused power directly from the battery through a relay which uses the stock wiring signal as an input.

93FD3S

twokrx7 or bond007 wouldn't happen to have any pictures to illustrate the rewiring of the fuel pump would ya? Or maybe a color key for the wires? I'm pretty sure its simple, just don't wanna get stuck when I pull everything off. I sure hope that Walbro 255lph doesn't let me down. Been using it for about a year with out any problems so far on stock twins. thanks..Tony

Snook

iTrader: (12)

Tony I don't think the walbro will be good for more than 400rw. There is a thread here that states the supra pump which flows 5lph better than the walbro cuts out at 415rw on our car. Its strange because on supras its good till 550rw!!!

bond007

I don't have anything, at least not yet. I haven't gotten around to getting the supporting stuff in place to do it. IIRC, the FC3S guys do this fairly often, they may have some documentation, it is more or less the same. All of the wiring information is in the factory manual, you just have to extract it.

All things being equal, if the same pump is only good for 415rwhp on stock FD fuel lines/system, then the Supra probably has a component with a larger capacity than the FD which limits the flow in the FD. There are more than just one variable to make such a comparison, one easy one that comes to mind is the Brake Specific Fuel Consumption of a 13B vs. the Supra motor.

twokrx7

iTrader: (1)

I don't have a diagram but it's simple.

Disconnect the fuel pump resistor.
Run a heavy gage fused power supply from the battery to the pump area.
Install a relay in the fuel pump area and use the factory power supply to trigger the relay, thus supplying full battery voltage to the pump whenever the ECU calls for the fuel pump to be on. I used a factory fuel pump relay.

It's a lot of work. Suggest you carefully disassemble the fuel pump harness connectors and use the existing crimped on conns and some high quality spade conns to simplify wiring.

93FD3S

twokrx7...thanks for the help. I also recall another way of rigging the fuel pump for constant 12 volt. It involved the little silver box located under the Brake booser. I forgot the term for it maybe fuel switch or something like that. Definitely need more sleep.

sevenin7

Guys i need a help .
A few days ago , i put a new Sard fuel pump in stock tank without modifications , everything o.k .
This pump as told me the dealer is the biggest fuel pump in tank for direct fit ( 280lt/h ) , and i beleive this is true . Outside of the Sard box writes << FD3S - FUEL PUMP - 280LT/H ) and other words in Japanese . The car runs very good , but ... no difference , about egt temperature , everythink is the same !
I would like to tell me your opinion about this !