Noisy fuel pump, feeder pumps & swirl pots

[Dive!Dive!]

Right then. I have my EFI install done , it runs but not finished the map yet.
The pump I have is horridly noisy - can hear it above the exhaust!
My install is like this -8 from tank to filter to pump to filter to rail to regulator return to tank. Hardlines front to rear of the car (8mm)
Both filters are under the tank on the pan , as is the pump, mounted on the bulkhead.
The pump is a new Walbro GSL392 255LPH. I have it mounted at an angle - the inlet is at pan level, and its at about 30-45degrees with the outlet higher. Fuel pressure appears fine / steady.

Is the fact I have it at an angle causing the noise ?
Will adding a feeder pump help the noise ? Easiest would be to do this inline. Adding a swirlpot will be tight for space. I have ones of these : http://www.webcon.co.uk/shopexd.asp?id=48 already in my parts box.
Alternatively - is there a quieter pump I can get ?

Its a mild engine <150hp
Cheers
Steve

[aircooledtechguy]

How you mount the pump makes a big difference in how loud it is. I'm not talking angles, but rather to be sure to have the black foam sleeve on the pump and use the provided Adel clamps. That alone helps I also like to isolate the clamps from the body by using the same rubber isolators the factory did for EFI pumps. Once I did that it was really pretty quiet. Walbro pumps are not the quietest pumps to begin with, but you should not hear it over your exhaust system outside the car. I can *just* hear mine at an idle inside the car, but it's located near my feet just on the other side of the thin sheet metal bulkhead, so. . .

Hope this helps. . .

[Dive!Dive!]

Thanks. I have the foam sleeve(s) , proper clamp and used a few 3/4 inch rubber tap washers to isolate the clamp from the firerwall (even the mounting bolts are sleeved...)
Its a loud whine....

Steve

[miniman82]

I went against the grain on mine, I don't like the idea of a filter before the pump. I think it can cavitate the pump. I just stuck with the tank sock>pump>10 micron filter>rails>regulator>return scheme on mine. Not much noise at all, for sure not above the exhaust.

[woodsbuggy1]

If you want a quiet pump, then intank is the way to go, if this is an option for you. I run railbuggys so fuel tank fabrication is expected, I am using a Subaru fuel pump assembly that bolts to the top of my fuel tank. The only time I hear it run is when it primes the fuel system and it is less than 3 feet away from me(behind passenger seat) this may not be an option for you but it works great for me.
Good Luck
Kenric

[Dive!Dive!]

Bitten the bullet on this and made a start. Tank drained and out, existing pump and filters out.
I've decided to go with a swirl pot. HP pump will be horizontal on the frame head pan, opposite side from the brake cylinder. Small custom 0.5 litre pot on the bulkhead next to it, LP pump on the same side as the brake cylinder feeding the pot. 100micron pre filter between the tank and LP pump. 10Micron HP filter moved to the rear of the car above the trans.
So I will have a LP circuit from the tank to the pot and return from the pot to the tank, and I've added a 3psi check valve in that return, so the pot will always be at 3psi. Return from the HP regulator also comes back into the pot.
I'll report back how it goes.....
Steve

[Dive!Dive!]

Right then. Got it finished, fuel in the tank, two leaks -one fitting the other a split hose (!), now sorted.
Seems quieter, but far from silent. Pressure is rock steady.

Now, I took a look in the tank through the sender hole with the pumps running - amazed at how many bubbles come through the return. These must be vapour as I cant see how air would get in the system as I have no leaks. anyone else noticed this ?

Steve

[Piledriver]

Could be evidence the pump is cavitating, and what you are seeing are fuel vapor bubbles.

I was always under the impression gerotor pumps (like most Walbros) are not as prone to that, but it's more likely they simply don't hate them as much as a roller cell pump does.

In any case the dual pump/sump should effectively keep the bubbles out of the fuel loop, but you might want to try eliminating any prefilters unless you have garbage shedding in your tank.

Keep any filters on the feeder and high pressure parts of the loop.

[Dive!Dive!]

Keep any filters on the feeder and high pressure parts of the loop

Yep, that's what I've done. I have a 100micron between the tank outlet and my LP feeder, the feeder goes into my swirlpot and the walbro is connected to the bottom of the swirlpot, Of course I have the large capacity 30micron filter at the rear of the car before the rails. I cant believe the walbro is cavitating - its fed with -6 tube directly from the half litre swirlpot, which is at 3 psi.......

[Piledriver]

I was thinking putting the feeder filter post pump in case it was cavitating, at least as a test.

Odd thought (probably not significant, but something I noticed)

I have an E85 sensor, and it also measures fuel temperature as a side job. (correlates well to the MAT and CLT sensors in at all temps after vehicle sits awhile)
My fuel gets surprisingly hot on the way back to the tank, like ~40+F degrees over ambient after a long run.
(sensor is on return side)

Pumping fuel heats it in general, and specifically right in the pump: it also picks up heat from the heads in the rails.
The added heat could easily cause/enhance or look like cavitation if the fuel was near its boiling point anyway.
(boiling point of winter blend gasoline is probably ~100F some places, here the daily temp can have a 50+ degree swing, it was ~70F here the other day at 4PM, the sensor was reading over 100F fuel during a 40 mile run)

At least any vapor is separated and has an easy path back to the tank with the feeder/sump setup.

All of the above is why I still cannot grok some OEMS going to returnless fuel systems on late model cars...
Perhaps a case of saving money at any cost (to the car owner)

I need to stick a TC in my fuel tank and see how it correlates to the sensors readings, maybe we all need a small fuel cooler loop or such.

[Dive!Dive!]

That's an easy test to do at some point - just take out the feeder pre filter....
Always more things to test.

I don't actually think it matters as the swirl pot is indeed doing its job of letting the vapour out the top, and I'm sure there is no vapour in the rails as the engine runs fine...