wondering why no one is doing just a simple inline fuel pump with return system instead of swapping for the walbro and doing the mods for that. i feel the inline pump would also eliminate the need to do the stock fpr mod as line pressure after the factory pump due to the draw from the inline pump would be dropped letting the stock fpr stay open most all the time.
seems this a far easier and less expensive way to go. please only replies that are valid and make sence.

 

But would the stock fuel pump allow enough flow through it when the in-line pump is trying to draw enough fuel to keep the rising rate regulator happy under boost?? I think the stock pump would not allow enough fuel through to supply the inline...even if it was wide open.

 

It should. The Vortech S/C kit uses an inline pump. At some point though the OEM pump would just become a restriction but, by that point the injectors would also be a problem. If you are going much beyond the power levels that the Vortech kit supports (~400 WHP) I would say do it right with a return style system with larger injectors. I would think the best plan is to have a plan. Determine what your HP goals are and build a fuel system to support that.

 

well looking at the fact nobody has had to upgrade or up size the factory fuel line size or output lines coming from the pump, i feel it would flow enough. the stock pump is insufficient to flow at those pressures, but with an inline pump creating most or the pressure, the factory pump would be close to just free flowing which would be enough volume to feed the inline. need to find out the free flow capabilities of the stock pump then the flow of the inline pump at 50-55 psi.

 

I have seen higher pressures with the Vortech inline pump so, the OEM can flow at a higher PSI.

 

as i have seen up to 85psi (when i was looking once) with the ati inline pump too. more could definately be had for sure.

 

keep in mind my reason for inquiring is looking to get approx 550rwhp and using the greddy emanage where injector pulse can be manipulated also with 750cc injectors.

 

With the Vortech inline pump and the FMU . It raises 8psi for every 1psi of boost . So with 9 psi of boost , I was seeing over 120psi of fuel preasure

 

We (Skidazzle and I) saw over 100psi on the injectors when using the Aeromotive Tsunami pump. Too much fuel pressure for my tastes. With the return system, I will never see more than 70psi. Bottom line, the inline pump works well, but only by raising the fuel pressure to ridiculously high levels. For the extra cash, the return system is worth it.

 

the issue is not fuel pressure, it is fuel delivery. will an inline fuel pump deliver the required fuel to reach the horse power #'s which i am trying to achieve. after more research, and running equations set by rc and other sites, an inline fuel pump will work just as good as an aftermarket or in tank fuel pump as far as fuel delivery.
i am very surprised when i found out the fuel system on the Z was laid out the way it was. i have never run into a fuel injected car that did not have a return fuel line. unfortunatly i think nissan tried to save a few bucks by having the return (or bypass) happen still within the fuel tank. 10' of fuel line to try to keep at a constant pressure with a mechanical fpr is insane. but nissan never tried to engineer for people trying to get 500-600-700rwhp out of their fuel system. it may have saved them a few bucks to manufacture not having a return line, but dam, even stock the fuel pressure could not be consistent to what the motor needs then hurting fuel economy.
if anyone has a good answer why nissan did not do a return fuel system from the factory for manufacturing costs, let me know.
fortunately the cars i have worked on and built had return fuel systems and the fuel pressure stayed consistent no matter what you did. a vacuum source to the diaphrahm would raise pressure as needed. the market that the Z came out in was tight to say the least. so they tried cutting costs everywhere they could, (hence no power passenger seat and other goodies) to make the car more affordable, but dam, this is a very simple performance issue and fuel economy issue that a few bucks they saved in manufacturing seems irrelevent.
i can't wait to see opinions on this one, but i come from building other fuel injected cars (vettes) and have built the fuel systems and intakes on those. just surprised to see that an import car would be inferior in this area when every domestic i have worked on had a return fuel system.
please, if you are going to post, make sense and have a valid point.

 

FWIW the decision was made for Emmissions Regulations reasons...got to love the government

 

Bump.

Actually wondering for those looking for high rwhp. Do you think the Walbro + inline fuel pump would support 650+rwhp?

 

But with the inline vortech fuel pump , you build preasure with [out] lots of flow . And more flow would be needed to have return system . With the extra flow needed for a return system , the stock fuel pump may cause a restriction

 

i will be finding out for sure very soon as motor is going in tomorrow with testing following suit. i feel very confident it will supply more than enough fuel for my combo. looking for 600rwhp.

 

Also I believe it's used to reduce the fuel temp by reducing the amount of "tank to engine" trips. Something about reducing fuel evaporation due to heat. Bottom line like you said, it's ultimately Emissions Regulations.

Mustang Cobra's have a returnless as well and those guys are petty limited by how much power they can run before switching to return style. So were not the only ones..

 

Has any one tried an inline pump + Walbro with return system to achieve 650+rwhp?




I know this is an old thread but didn't want to start a new one.

 

yes it works. stock pump to a surge tank to an inline. Thats how SP rigs up some cars.

 

What happens if you use the intank walbro to feed a bosch 044 inline without a surge tank? Basically Walbro to Bosch to fuel rails?

 

what are you looking to do, bump fuel pressure or volume?

If pressure, then ya walbro to bosch would do it.

If volume, 2 pumps inline would be limited by the smaller pump, so it wouldnt push much more than the walbro. Thats why you use a surge tank to give you a large volume to feed from.

 

Gotcha, volume is the goal here for me. Im using a -6an feed line off of the oem pump assembly and was going to run the Bosch 044 inline and then continue the -6an to the fuel rails. By adding a surge tank would I just need one inlet for fuel and one outlet to the Bosch or should I being searching lol?