Walbro 255

[trunk-rattlin]

Just a bit of a hijack.

Ive got an rb30det in a 180sx. Its got a 500Hp walbro intank fuel pump in it. Its just at a workshop at the moment getting bigger injectors and a link g3 installed. ( i think they are evo injectors they have sorced). Before it gets put on the dyno, do i tell them i dont want it to run anymore then 14psi? The fuel line pressures that have been mentioned, are these the same through all turbo nissan motors? I wasnt aware how boost affected fuel line pressure.

[GeeTR]

...What they do is wire relays to bring the second pump online in times of high demand . The downside is what if the wiring/relay failed and the secondaryt didn't start ? Bang ?

More info/pics would be interesting!

Though... just as the factory ECU's on R32's trigger a soft earth for the f.pump; lower flow at idle, the dual "trigger extra pump when needed" Iv seen before. Tru, full load and the pump (for what ever reason) doesnt kick in... boom (ok ok, a cheap closed loop fail safe could be made)

The wider picture though, contains the fact that your using two fuel pumps to provide the vital injector head pressure. In reality if the second pump in a "both always on" situation EVER fails, you could lean out and det a motor, where a single pump should drop pressure more rappidly.

Correct, there are many items in even a stock car, could fail could kill a motor, partially stuck injector, manufacturing dag falls off an oil filter and goes through motor etc etc, but it still plays on my mind.

A single unit that does the job becomes tempting...

Just a bit of a hijack.

Ive got an rb30det in a 180sx. Its got a 500Hp walbro intank fuel pump in it. Its just at a workshop at the moment getting bigger injectors and a link g3 installed. ( i think they are evo injectors they have sorced). Before it gets put on the dyno, do i tell them i don't want it to run anymore then 14psi? The fuel line pressures that have been mentioned, are these the same through all turbo nissan motors? I wasnt aware how boost affected fuel line pressure.

Really, even if your pump does drop pressure past 14psi, your tuner could most likely, beef up the cells that are hit in those more loaded conditions.

If you weren't aware that boost pressure effects fuel pressure, i would strongly recommend talking over with your tuner about pumps and what you know about Walbro's.

My opinions only.

[discopotato03]

Also sort off ..... related .

I think I did read somewhere that the GTR's multi voltage fuel pump powering device works at different voltages (lower in low ?) than a GTST . I fitted an R33 GTR pump to my S2 R33 GTST and it is a little louder though nothing to cry about .

I'd like to now how many voltage steps the GTR switched resistor thing does and how they differ to other Nissans , I just wonder if the GTR's gadget may help people with big pumps in street GTST's .

I was told about a mod to the Walbro that some used to do to get more out of them , its dangerous and illegal and I don't want blood on my hands .

I think the bottom line pump wise is use an adequately sized one for your power goal and not go over the top because it just creates avoidable problems .

Edited February 17, 2008 by discopotato03

[Sydneykid]

Also sort off ..... related .

I think I did read somewhere that the GTR's multi voltage fuel pump powering device works at different voltages (lower in low ?) than a GTST . I fitted an R33 GTR pump to my S2 R33 GTST and it is a little louder though nothing to cry about .

I'd like to now how many voltage steps the GTR switched resistor thing does and how they differ to other Nissans , I just wonder if the GTR's gadget may help people with big pumps in street GTST's .

I was told about a mod to the Walbro that some used to do to get more out of them , its dangerous and illegal and I don't want blood on my hands .

I think the bottom line pump wise is use an adequately sized one for your power goal and not go over the top because it just creates avoidable problems .

All of the R32/33/34's I have tested have 2 voltages for the fuel pump, one around 9 volts and the other 13.8 volts. I haven't spent a lot of time on it but what I have observed is 9 volts at idle, although it seems to be anytime the ECU is running closed loop via the standard (slow and narrow) lambda sensor. Which is logical when you think about it.

Cheers

Gary

[GeeTR]

I just wonder if the GTR's gadget may help people with big pumps in street GTST's .

Theres a person or two on SAU who's used a Jaycar kit off the AFM signal in his GTST. He's set up the unit to switch the larger pumps earth, through a resister when at low AFM signal output. I think he said it had strong effects on the fuel temperature.

Something like this i would assume, Jaycar kit KC5377

Edited February 18, 2008 by GeeTR

[mark_sudakov]

It's a matter of cutting the bottom plate off the stock bracket (normal wire cutters will do it), putting 2 clamps on to hold the walbro and using 2 crimp connectors to connect the wires. I'm not exaggerating how easy it was.

So the Walbro pump does require modifying. I was under the impression nothing needs to be cut, just electrical side of things. And i hve also recently found that the stock R32 pump is almost twice the size of the Walbro, so it wont drop straight in. Is there any tuts to show how it actually fits?

[The Mafia]

All of the R32/33/34's I have tested have 2 voltages for the fuel pump, one around 9 volts and the other 13.8 volts. I haven't spent a lot of time on it but what I have observed is 9 volts at idle, although it seems to be anytime the ECU is running closed loop via the standard (slow and narrow) lambda sensor. Which is logical when you think about it.

Cheers

Gary

Gary, I tested my Powerfc a while ago and I am 90% sure they do away with the stepped voltage setup and run 14 volts full time.

Can you confirm this?

[mark_sudakov]

It's a matter of cutting the bottom plate off the stock bracket (normal wire cutters will do it)

Why does the bottom plate need to be removed?

[discopotato03]

Hi Mafia , I bought a late R33 GTST PFC just before they dried up and mine does the two stage thing . Basically as soon as I breath on the accelerator the second squadron of wasps start pedalling , at idle they take a rest .

A .

[The Mafia]

mine on idle reads 14 volts. Strange.

Nismo 275lph pump is so quiet I can't hear it.

[Fastrotor]

Mafia,

Whats your nismo part number for your intank ? 17042-RRS41 ? Nismo website lists this pump for R33 GTST, so does slide on this site.

Now i went looking for info as i prefer to check all claims myself as a due diligence thing, and going by the nismo website themselves, there pump chart lists the GTST pump as 4.1 Lpm @ 3Kg/Cm ( 246Lph @ 42.7Psi)

There GTR pumps are still only rated at 42.7psi , abeilt at your mentioned 276 Lph.

So my questions to you are, what part number did you use, where did you get the high pressure rating you mention ( 70Psi) at there 276 lph flow ? Have you seen a flow curve for these pumps you can point me to ?

Gary

For reference :- http://www.nismo.co.jp/en/products/competi...df/hf_fpump.pdf