Considering a Walbro 255
 

So my fuel pump died this past week. I have a S4 N/A, with exhaust and intake, but over the winter I want to boost my engine cause I won't be driving the car. So that brings me to a dilemma, do I replace the stock pump, with another stock pump (then have to replace it when I turbo the car) or do I get a Walbro, which is about $70 cheaper. The problem with the Walbro is I need to wait a week for the install kit, and I could have a stock pump in the car tomorrow, and running. If I do install a Walbro, it's going to make the install more complicated, so that's why I'm asking those who have done the install. Is the Walbro a direct install; the stock pump has a sock, a ground, and a 12v connection, plus the hose to the pressure line, is the Walbro different, do I need to fabricate or change anything? And with the increased flow, can I run the stock vacuum fed FPR, or do I need an adjustable one like an Aeromotive?

Anyone?

I don't recommend walbros, too hit or miss on quality. Have personally had one fail.

I would get a used stock pump to hold you over, then go for an uprated pump when you do the turbo swap. I will recommend the aeromotive stealth 340.

Consider a better pump. Denso supra pump,Bosch 044. Get a oem pump they are way more reliable and built with better quality.

Denso, walbro, etc install same as stock. But aftermarkets usually need a regulator in addition.

Turns out a friend of mine had a spare Walbro, I slapped it in tonight, and I gotta say I'm fairly happy with it, I don't notice my 3800 rpm hesitation anymore, I guess the old pump wasn't putting out enough fuel when the secondary injectors kicked in, and caused the car to lean out. Runs pretty good now, I'm just happy to have my 7 back on the road, and I've got a pump that can handle the extra demands when I go turbo. Thanks for the input, I think I'll be getting a regulator in the next couple of months just to be on the safe side.

You shouldnt be running a walbro on a n/a car. Get a stock pump off the forum when you can. They go for dirt cheap anyways.

If you're already running the walbro, you should be getting a regulator in the next couple of DAYS to be on the safe side.

I have a stock TII pump for sale with a new filter if you're interested.

On an NA, the appropriate replacement is a stock NA pump. Anything else without some way of adjusting fuel pressure is going to make the car run too rich. It will do nothing but cost power and fuel.

+1 Exactly.

buy a used stocker for the interim.

as for everyone else... i have had my best luck with walbros despite all the horror stories. a brand new denso supraTT pump lasted half a dozen passes on the dyno where the previous 255 Walbro took 450whp abuse daily for about 3 years with a kenne belle boost a pump bumping voltage so that it could actually make that power. that same pump is now in my car and has been fine for the past year.

that failed denso was replaced with the new walbro 400 pump to make 500whp with the kenne belle turned off to static voltage and has tons of room to grow even with the stock S5 TII fuel hard lines.

so my latest experience was

cliff notes: walbro 255 still working was replaced with Denso supraTT pump which failed as soon as a hint of power was being made, replaced with a walbro 400 which has made just shy of 500whp for about a year now. old walbro that pushed 450whp for years still kicking it in my personal TII and has been fine for even long road trips for the past year(pump being 4 years old now and has seen no less than 300whp regularly).

i'd imagine it could support 600whp even with stock fuel hard lines with a single pump, more with a slightly larger main supply hard line. never did a volume test as the pump was installed on the dyno when the denso took a big shit.

to this day i have never seen a walbro personally fail.

I know this is a few months old but no point in making a new thread. I also have a 255 Walbro (previous owner) in my S4 N/A.
Would this (aeromotive 30-70psi):
Aeromotive 13155 - Aeromotive Compact EFI Fuel Regulators - Overview - SummitRacing.com
With Sard Adaptors:
SARD Fuel Pressure Regulator Adapter for Nissan, Subaru, Mazda - More Japan :: Since 2003
&
Fuel Pressure Regulator Adapters - More Japan :: Since 2003 (Page 2)

Help regulate my fuel system enough to keep the Walbro in there? I'm thinking long term with turbo, so I will buy an FPR at some point most likely anyways. Less money waste in the long term maybe?

used a supra fuel pump

Yes that SARD adapter should be the correct adapter for an S4 N/A. You can use an adapter for a Toyota M12x1.25 SARD #69016 or like Tomei #185107 at this link Tomei FPR ADJUSTABLE to delete banjo bolts on the other parts of the rails as well. Or you can get a M12x1.25 to -6AN adapter for a Solex carb and run all -AN since the FPR you're looking at includes them. But I take you want to use regular hose since you're looking at those hose barb fittings?

Mine (S4 TII) is like this with the banjo deleting M12x1.25 Tomei adapter and another $1.50 male-male 1/8" NPT union fitting. Does clear TII UIM but can't speak for an N/A with the bolt on flange adapter. Would probably work similar since it sticks out the front on an N/A anyways...
Attachment 694642

Cool setup :)

There is a set screw on top to adjust base fuel pressure right? Did you use a fuel pressure guage to calibrate your FPR? I was thinking about buying a dry one just to calibrate the regulator itself, and make sure its doin its job. I just wanna make sure its ~30 PSI where it should be. Maybe I shouldn't be so cheap and buy a liquid filled one. Hmmm...

Yes there is adjustment for pressure on the top of the Tomei regulators, read the link I posted previously or below for info on the FPR.
Tomei FPR ADJUSTABLE

You can also use that link to determine if the bolt on adapter will fit as it lists all dimensions of said adapter.

Yes you should always set your FPR using a liquid filled gauge. 30psi is too low, it should be 38-40psi I believe. Please check the FSM for actual pressure requirement when setting. I always remove the gauge from the FPR and plug the gauge port after I am happy with the pressure setting.

-----

For all the N/A guys running Walbro pumps, why the 255LPH? Are you all using the the high pressure model on top of that? I'm pretty sure Walbro does have a 190LPH that would probably suit a N/A motor much better than a 255LPH HP pump. That is if you're going to buy a Walbro.

As for the comments of Walbro being crap, I've never had one die on me, as well as a number of friends. Realistically....

Walbro = Made in China.
Aeromotive = Made in China.

The Aeromotive products don't really scream better to me. I'd run a Magnafuel FPR over an Aeromotive any day of the week. I chose to use a Tomei FPR over Aeromotive even though I have an Aeromotive sitting on the shelf. Granted I have both styles of Tomei FPR sitting on the shelf also, it was all a matter of personal preference...

A regulator and a good gauge - quickly - is a good idea. I'm not sure about the wisdom of a used pump - maybe I'm prejudiced because that's bitten me.

Most of the gauge-included FPRs seem flaky. I wish I could find better reviews. Buy a good name from a good vendor - probably will pay more. I worry about generic fuel pumps with lots of adapters.

I understand the thinking behind having way more (x component) than I need, but you have to be thorough and adjust for it, as pointed out above.

The walbro on a stock TII will push idle fuel pressure up to 55psi. I know from experience. You need an adjustable FPR to get it back down.

Walbro's application list shows GSS315 (255LPH) and GSS341 (255LPH HP) for S4 or S5. Walbro also shows GSS315/341 are for early MX6/Protege. There is a 190LPH listed for this application, so I'd assume it would fit and suit a N/A S4 or S5 a bit better. Walbro GSS278 is the MX6/Protege part number.

Straight off the Walbro applicatin list on the website, nobody's ever tried this on an N/A?

Phone app crashes when I try and edit my other post...

So both bumps are physically identical.

GSS278 (190LPH)
Attachment 694427

GSS341 (255LPH High Pressure)
Attachment 694428

GSS278 Bottom, GSS341 Top
Attachment 694429

This place typically has good prices on Walbro pumps and install kits;

Auto Performance Engineering - Walbro fuel pumps and more

I would recommend a regular 190 L/hr pump for a S4/S5 n/a and leave the 190 HP, 255 and 255 HP for the turbo folks.

It is always wise to use an aftermarket adjust FPR with the larger/higher output aftermarket fuel pumps to ensure that the pressure differential across the injectors stays constant no matter the RPM and/or load on the engine.

Also found this Blox piece that may fit a stock TII S4 rail w/ stock banjos. Looks like it might bit long. Would be a cheap solution to pop a gauge on the end of the seconday rail.
Attachment 694337

Or a cheap all in one gauge solution possibly...
Attachment 694338

Well unfortunately I ordered and recieved the Aeromotive FPR already, and that sard adaptor. I think there is a store around here called mopac that carries a reasonalbe selecetion of AN/F.JIC adaptors, paying for shipping on these already expensive parts is the real expensive part, so hopefully I can find the right stuff locally. I have a $50.00 autometer guage which I think will be good enough to initially set the FPR itself, then I'll take it off. There's a 1/8 NPT guage port on the FPR already. I'll get it going within the next few days I hope and let you guys know how it goes. Would be tomorrow for sure if I didn't work :(

The only problems I can forsee is that the guage will probably suck, and the walbro may still pump too much. But in all reality, the aeromotive should be able to handle it. If not, I have a denso stocker sitting around...which would require spicing wires (current walbro is wired to a quick disconnectable type connection).

As far as pressure goes on my N/A...which should be similar to TII (since there would be no boost at that point) the 1986 FSM suggests 35.6-37 PSI at the regulator with vaccumm hose unplugged, and only 28.4 PSI with it plugged in.

I'll make a post here again after I make some progress. The car is not being driven in the mean time. ZX2 daily driver at the moment.

Quick update, gonna have to buy a 90 degree fitting to gain some clearance for the fitting coming put of the guage port. Currently the straight fitting hits the thermostat housing. Worse comes to worse I can T the return line to install the gauge. Had to modify the sard adapter because the bolt distance was about a 1/2 inch to close together. Gonna email more-japan to let them know. I'll post some pics when I'm done.