Walbro 255 Fuel Pump Doable?

[moroza]

Quad-post FTL.

Firefox claims that BFc tries to reach some Yahoo API server. Whatever it is, posts are taking me 5 minutes to upload and not reliably at that. Deleting takes just as long so you know what, I'm going to let this spiffy "Automerge" "feature" do its thing. If it's smart enough to consolidate posts made hours apart with different content, it should handle this. Without using a Yahoo API FFS...

[janders211]

Summary:

Walbros are proven pumps.
Walbros are cheaper than OEM.
A Walbro will work in your car.

BTW- anyone know offhand what the stock 540i pump is rated at in lph @ voltage?.

[moroza]

Hm...apparently I'm not the only one having problems with doubleposts. Stutterposting anyone?

[5mall5nail5]

Summary:

Walbros are proven pumps.
Walbros are cheaper than OEM.
A Walbro will work in your car.

BTW- anyone know offhand what the stock 540i pump is rated at in lph @ voltage?.

Less than a walbro

... and more reliably - oops did I say that?

[acet]

We got the point, Moroza

acet, he is right about some of these pumps being really loud.



Understood. I think you're confusing flaming with something else. It's not a bad thing to seek a cheaper alternative. It's just that you can't arbitrarily throw in a fuel pump that doesn't match the specs of the standard pump.

Then talking about turbos...okay now. Turbo M60? Go for it, but it gets annoying when there is so much dreaming and promising but little ever gets done.

You'll get flamed if you post your ideas without any research on your end...

It's not about mods that people would do...it's about mods that won't work.

I know you are pretty cool...believe me, I see that and it's a good characteristic on your end. The thing is that if somebody doesn't agree with you they aren't a "hater". They just simply don't agree, and they may have their reasons.

If you are actually going through with your turbo plans (and I wish you the best if you do), then sure, it makes sense as a "while you're in there" sort of thing. But if you're just spouting out BS about some turbo setup that you dreamed up in class and have a $800 budget for and little understanding of the subject, then, well, you're a moron.

Not saying you're either of the two.

You're completely right. I should look at my ways too. They are far from always being right. I apologize if I posted somethere here that would offend anyone.

I threw together some numbers with a friend of mine. He is way more knowledgeable than I am. He said I'm looking at around 8 -10K all together. Because I don't just have 8 -10K to blow on a build right now, it does remain my dream...

His, however, came to life....1400ph supra..built by Batlground. Call if you don't believe. www.batlground.com

I, however, am planning to start sometime closer to the winter...

Anyways to sum it all up, I got the pump and I will be the one to face consequenses if it fails. I will keep you guys posted. Thanks Denton.

[Shuasha]

I just installed a Walbro in my SC 532 and I'll say that it's not simple. You pretty much have to force it into the mount and cut the bottom of the mount off. Also, if your tune isn't for that pump, the FPR usually can't dump enough fuel at idle so you'll be rich. Just find a used stock pump or find a deal on a similar one.

[cssari]

Shop around you can get the OEM cheaper BavAuto has higher prices than many others. Try Pelican, BMA, Autohauz, GermanAutoParts, eBay, Craigslist, etc, etc.

+1
195$ from bma!

[russiankid]

I hope you guys know that the FPR operates off of vacuum. So if you have increased pressure in the fuel system, it will still dump the same amount of fuel back into the tank as it were with the stock pump. There is no way the FPR can detect that there is more pressure in the system and that it needs to maintain 43psi.

[janders211]

I hope you guys know that the FPR operates off of vacuum. So if you have increased pressure in the fuel system, it will still dump the same amount of fuel back into the tank as it were with the stock pump. There is no way the FPR can detect that there is more pressure in the system and that it needs to maintain 43psi.

This is incorrect.
The fuel pressure regulator does not let a set 'volume' of fuel return to the tank (well, at least not until you reach the limits of the return piping). The diaphragm begins to open at close to a set pressure, not at a set volume...i.e. at a ratio of pressure between the fuel on one side, and the signal port(vaccuum port) on the other...increased vaccuum decreases pressure from the initial pressure opening point, as boost(for most FPR's) increases it.

So, no-swapping from a 125lph pump to a 250lph(arbitrary numbers) pump will not double your fuel pressure.

People have shown this swapping from one pump, to dual pumps(parallelll) before...i.e. roughly the same line pressure.

[kell13y]

I have seen a generic walbro installed in a 525i E34 using all the stock mounts, sock, wiring, etc, and function perfectly down to the last gallon in the tank. If anyone local would like to install one I would be glad to help you out with it.

[russiankid]

This is incorrect.
The fuel pressure regulator does not let a set 'volume' of fuel return to the tank (well, at least not until you reach the limits of the return piping). The diaphragm begins to open at close to a set pressure, not at a set volume...i.e. at a ratio of pressure between the fuel on one side, and the signal port(vaccuum port) on the other...increased vaccuum decreases pressure from the initial pressure opening point, as boost(for most FPR's) increases it.

So, no-swapping from a 125lph pump to a 250lph(arbitrary numbers) pump will not double your fuel pressure.

People have shown this swapping from one pump, to dual pumps(parallelll) before...i.e. roughly the same line pressure.

The FPR runs off of vacuum. It is just a simple vacuum diaphragm with a valve. It really just depends on the engine vacuum so for example when you're at full throttle, the diaphragm is closed thus your fuel injectors have constant supply of fuel. When idling, your vacuum is around 22lbs, so the diaphragm is open because your injectors just don't need all that fuel.

At least that is how I see it.

[janders211]

The FPR runs off of vacuum. It is just a simple vacuum diaphragm with a valve. It really just depends on the engine vacuum so for example when you're at full throttle, the diaphragm is closed thus your fuel injectors have constant supply of fuel. When idling, your vacuum is around 22lbs, so the diaphragm is open because your injectors just don't need all that fuel.

At least that is how I see it.

No- Vacuum alone does not operate the fuel pressure regulator.
It is the pressure differential between the fuel side of the diaphragm, and the port side (vacuum/boost). Pressure differential opens it....not absolute vacuum vs. atmospheric.


Think of it this way:
A 43psi fpr (with no vacuum attached) fpr will keep the rail at 43 psi . If you start pumping more fuel into the rail(with no vacuum attached) it will still open at 43psi, and the only thing that will change is the fuel rate (in theory)...i.e. more volume will flow through the rail, and back to the tank- but it will still be 43psi sitting behind the injectors, thus they will not flow more per msec open into the combustion chamber. Changing the vacuum/boost will change the pressure(vs. atmospheric) at which the fpr opens, but will not change the pressure differential that it opens at (i.e. it will always be about 43psi over whatever is on the reference side of the diaphragm).

[russiankid]

I never knew that there was a spring inside that would release pressure.

[janders211]

I never knew that there was a spring inside that would release pressure.

whenever I don't understand something I take it apart, and then whatever is left I take a dremel and cut it in half..haha.

random note- but I have had my car run (suprisingly) at 'base' fuel pressures from 35 to 75...only at WOT, where fuel correction was taken out of the loop did it really go to crap.

[russiankid]

So if you're idling the car without the vacuum line it still maintains 43psi. How do you increase volume at full throttle as there is no vacuum? It would still then have the same flow rate as it would on idle no? The pump wouldn't put out more, it already puts out more than needed.

[janders211]

actually at idle (assuming 43psi at atmospheric) and you had -20psi of vacuum...your fuel pressure would be 23psi (measured against atmosheric).

[russiankid]

Unplugging the vacuum line at idle would be the same thing as having the car at full throttle....volume wise. According to what you said earlier, pressure doesn't change, only volume does.

[tonyroc14]

I'm confused with all your 150lph, 250lph, FPR, vacuum, boost, return, spring...


lol

[janders211]

I'm confused with all your 150lph, 250lph, FPR, vacuum, boost, return, spring...


lol

haha- try saying it in a thick british accent- for some reason it makes a lot more sense then.2

[acet]

Ordered that TRE pump and installed it. Here's the link to a DIY I wrote:

http://forums.bimmerforums.com/forum....php?t=1245212

[ninetyseven1]

I just installed a 255lph pump in my 540i. Is this pump going to make my mileage worse? Has anyone experienced this?

[ross1]

I just installed a 255lph pump in my 540i. Is this pump going to make my mileage worse? Has anyone experienced this?

No, thanks for dragging up this shit show.

[JThomp33]

I installed the TRE pump back into my 540i/6 in 2016 and the car has run fine since. I also replaced all fuel lines in the engine bay to and from the fuel rail, clean the rail, "rebuilt" and cleaned the injectors and installed an new fuel pressure regulator. MPG is 18-19 around town and 22-26 on the highway. For variable purposes- I have 268,XXX on the motor, custom exhaust and a 3.15 LSD.

[Sir Montalbon]

No, thanks for dragging up this shit show.

However, I did find Jander's post later in the thread amusing and informative...