dual fuel pump questions

[bl3ujay07]

I accidentally came across a thread on dual fuel pumps a while back and have been wondering about the set up. I bought some power enterprise 850cc injectors for my sr20 with a gt2871. I checked out the power enterprise site and it states that 260lph fuel pumps are required.

I have been running a walbro 255lph fp since stock 370s to 550s and now, 850s. I am currently at 1.1 bar of boost on the stock fpr and want to up the boost to 1.3-1.4 bar of boost when my brothers 2jz sc300 is finished (he is shooting for 400+ hp, automatic). I have seen people say that the walbro supports up to 500+ hp (which i don't really trust) but have been searching for single fuel pump that would be more reliable, like the bosch supra tt and the hks unit. Unfortunately, both are expensive (as in out of my budget right now) and i have a spare stock 300zx fp (up to 260 lph) that my brother was going to install on his stock s13.

Can I run on a dual intank fuel pump using the walbro and the 300zx or would it be better to run two of the same fuel pump like walbro-walbro or 30zx-300zx?

If so, i want to try and make it so the second fuel pump (300zx) kicks in at wot. Anyone know of a way to do so, for instance people having nos activated only at wot.

[mattsil80wis]

your running fuel reguardless if its WOT or not its still 3 bar....just hook it up all together...what kinda power are you making anyway? probably only enough for a single pump anyone

codyace + mattsil80wis

[tt300zxFREAK]

What kind of power are you making? TT Z32 fuel pump is good for over 700whp. I'm gonna go out on a limb and say that would be more than adequate for you.

[bl3ujay07]

700+ whp on stock fuel pump? Can anyone else confirm this? Im only at aroun 300+ hp but am thinking of switching from gt2871r to a gt30. i dont want to starve the motor from the lack of the fuel because of the pump not meeting the demands of the injectors.

Edit: meaning later on in the future, trying to get the most out of 850cc without blowing my motor because of simple fuel pump.

[bl3ujay07]

your running fuel reguardless if its WOT or not its still 3 bar....just hook it up all together...what kinda power are you making anyway? probably only enough for a single pump anyone

codyace + mattsil80wis

If so then why would power enterprise recommend a 260 lph pump? What would be the need of upgrading the fuel pump from a stock 240sx to something like a walbro fuel pump then? The fpr is still regulated at 3 bars right?

[tt300zxFREAK]

700+ whp on stock fuel pump? Can anyone else confirm this? Im only at aroun 300+ hp but am thinking of switching from gt2871r to a gt30. i dont want to starve the motor from the lack of the fuel because of the pump not meeting the demands of the injectors.

Edit: meaning later on in the future, trying to get the most out of 850cc without blowing my motor because of simple fuel pump.

Fuel Pump TT (new OEM) (http://www.z1motorsports.com/product_info.php?cPath=6_17&products_id=1555) I run the stock pump and I'm over 500whp. Most Z32s with big power run dual pumps just incase. But the stock tt pump can handle a lot of power. Also, why PE850s? Seems like overkill IMO. Don't get me wrong their great injectors and I have them in my Z.

[bl3ujay07]

Why not? gt2871r user run 740 and say they are hitting 80% duty cycle easily so why not? Had 550s first and they got maxed out like nothing.

[VQMaxFan]

Im pretty sure you would need to upgrade to -6an fuel line from the tank to the rail before you max out a walbro 255hp, also you might want to invest in an AFPR (aeromotive/sard).

[fliprayzin240sx]

Single Z32 TT pump will be enough. IIRC, it has the same flow as GTR pumps if not close to it. I'm running a single R32 GTR pump on 850cc SARDs and GT3586. If I have enough fuel for this turbo, you shouldnt have any issue with a teenie GT2871R. I have yet to see my car hit 80% duty cycle

[R33E8]

Why go for the z32 pump when you can buy 2 walbro's and run them in parallel for less? It will support more power as well..

[undesiredshoe]

Ive run 18 psi on e85 with a walbro 255 and 1200cc injectors


If so then why would power enterprise recommend a 260 lph pump? What would be the need of upgrading the fuel pump from a stock 240sx to something like a walbro fuel pump then? The fpr is still regulated at 3 bars right?

They recommend it but its not necessary and its not about how much pressure a fuel pump can pump, its about the flow.

[bl3ujay07]

Single Z32 TT pump will be enough. IIRC, it has the same flow as GTR pumps if not close to it. I'm running a single R32 GTR pump on 850cc SARDs and GT3586. If I have enough fuel for this turbo, you shouldnt have any issue with a teenie GT2871R. I have yet to see my car hit 80% duty cycle


So then should i be trusting my walbro with this or should i swap the walbro for the OEM 300zx?

[R33E8]

So then should i be trusting my walbro with this or should i swap the walbro for the OEM 300zx?

Why would you want to go with an OEM 300zx pump instead of 2 walbro's? It will flow a lot more, and cost a lot less..

[codyace]

Why is this even this long.

Single 255HP or a single 300zx TT pump will suffice. No need for two.


Although I run two, because I'm weird that way.

[jspaeth]

Let me ask a potentially stupid question.

Is it possible to OUTFLOW the FPR?

AKA....you are supposed to have 36 psi at idle in the fuel rail, and the FPR is set to a certain point.


Now, you throw on 2 fuel pumps, and the flowrate goes up DRASTICALLY....presumably you have to looosen the FPR to get the pressure back down to 36 psi.

Is it possible you can't make the FPR loose enough....aka....the fuel pumps are flowing so much that you can't get the fuel pressure down low enough?

Just some food for thought.....my guess is that this probably isn't an issue.

[bl3ujay07]

Why would you want to go with an OEM 300zx pump instead of 2 walbro's? It will flow a lot more, and cost a lot less..

Well, if you read my original post, it says that i ALREAADY HAVE the 300zx fuel pump on hand and have ONE walbro on my car right now.

[Master Chief]

"Is it possible to OUTFLOW the FPR?"

YES. An with two pumps and stock FPR, this will surley happen.

[jspaeth]

"Is it possible to OUTFLOW the FPR?"

YES. An with two pumps and stock FPR, this will surley happen.


I guess that is kind of "intuitive"...right?

But let's say you have an adjustable one. Presumably when you put the second pump, in you would have to "loosen" (reduce pressure) the FPR to get it back to spec.

What if you can' loosen it enough, i.e. you can't get the FP BELOW say 50 psi?

Yikes!

[VQMaxFan]

Also if you have an s14 rewiring the pump is a must.

I guess that is kind of "intuitive"...right?

But let's say you have an adjustable one. Presumably when you put the second pump, in you would have to "loosen" (reduce pressure) the FPR to get it back to spec.

What if you can' loosen it enough, i.e. you can't get the FP BELOW say 50 psi?

Yikes!

Not sure but it would seem in this case like that would be the cause of a faulty fpr. Although im not positive on this.

[essforteen]

the subaru people have been doing for a while now and this is what ive found!
Buschur Racing Dual Walbro Fuel Pump Setup - NASIOC (http://forums.nasioc.com/forums/showthread.php?t=1152071)

[Master Chief]

I guess that is kind of "intuitive"...right?

But let's say you have an adjustable one. Presumably when you put the second pump, in you would have to "loosen" (reduce pressure) the FPR to get it back to spec.

What if you can' loosen it enough, i.e. you can't get the FP BELOW say 50 psi?

Yikes!

If you wont be able to use the FPR to lower the pressure back to standart, then you might be able to get away with it, if you have some kind of STAND ALONE, to allow you to reduce the injector pulse width.

Depending how far from the stock pressure you are, and what injectors you have , your iddle may suffer.

I was thinking at the time, using two pumps, but only using one, below a certain boost, and only above that, turn the other one on.
This may cause some problems during the turn on and off , of the other pump.

I am going to use just on walbro in the tank, and a surge tank with an AEROMOTIVE i think..... I feel its the safest and best way, though not the cheapest.
On the other hand, if you max out the walbro, you are probably alread invested pretty much in the engine - why cheap out now.

[txq45]

If you go to dual fuel pumps you'll also need a controller that has been modifed for the additional load or you can put the second pump on a mirco switch controlled by boost pressure..
If you change to a Areomotive type FPR the pressure is high to start but you just adjust it down to the correct one.
The 300zx fuel pump will work for your setup if it for a Twinturbo . will not work if it's from a NA... I ran the TT pump with 24psi on twin 2860rs with no problem.
I've also upgraded to the twin Walbos and modified controller along with the 6 an fuel lines to and from rail to tank along with the Areomotive FPR.

[Spring Break '92]

So what if you are running two fuel pumps, one being the stock in tank pump and the other an inline pump, do you all think that setup over runs a stock FPR?

[MavericStephenc]

Why not run dual in tank walboro 255's? just hook them up to a y hose connection, then run -6 with an inline fuel filter to the rail?

EDIT:essfourteen beat me to it

[GroundPerformance]

I'll be running this setup as well. Can anyone with this setup post pics. Also where to get a decent Y fitting for this application. THanks!

[codyace]

I've run an in tank 255HP with an inline 255HP forever.

[whitey240]

I run a single Walboro 255 with 1000cc injectors supporting 491whp and daily drive and race it. Never had an issue. I ran the same pump on the car when I had the 850cc injectors with a 406whp setup. You will be fine with the Walboro that you have in the car today. Good luck with your setup!