Has anyone tried the new Holley 12-150? I can not find any details on the pump other than the comments about a gerotor design. The flow curves on the holley web page show a very flat pressure that looks appealing.

 

If you could, post a link to the pump

 

http://www.holley.com/data/Catalogs/Fuel%20Pumps.pdf

page 13

 

Looks like it could be a good alternative to our stock lift pumps. It should be a lot quieter than a vane style pump too. It doesn't say that it is rebuildable like the Holley blue and Black though, and it costs $60 more than a Black and $100 more than a Blue. It also doesn't say if there is a warranty. If I ever have trouble with my Black, this is something that I would check into.

 

I talked with Holley about this pump this morning and the main concern they had was with the internal pump clearances. The clearances are very tight and without a pre pump filter they thought the pump would lock up. As usual they have not tested it on diesel and do not plan on testing it.

 

If everything Superduty claims about the Walbro 392 pump is true then there is no reason to even consider this Holley pump.

 

I was thinking about that today, but I have a concern with the Walbro set up. The life of the VP is about flow to prevent cavitation, lubricate, and to cool the electronics. The walbro setup may provide sufficient flow through the VP, but I do not have a flow meter to measure it or know how to calculate the flow through teh bypass line versus the VP. The majority of the fuel should flow through the bypass line rather than through the VP because there is less restriction down that path. The Walbro that is usally referenced is a 255 lph pump. This is 67 gph total compared to the factory lift pump at 80 gph through the VP. I think I saw on one of Superduty's postings that the flow through the VP was around 70 gph, and I don't understand this with the 255 lph pump. I don't know enough about the VP to be willing to drop the flow through the pump.

 

The VP has a feed pump built into it. All you have to do is provide pressurized fuel to the VP inlet (and thus the feed pump) and it will get all the fuel it needs. The rest will go via the bypass.

The lift pump doesn't move anywhere near 80 GPH and the VP doesn't need anywhere near 67 GPH. Probably more like 30 GPH. Your numbers are wrong.

The reality of a Walbro install is that with stock lines and a 1/4" bypass people are seeing 17 PSI at idle and 13 PSI at WOT. That is with ZERO pressure regulation, a totally open bypass. The Walbro is moving 70 GPH to the inlet of the VP44 under those conditions. Obviously most of it is going through the bypass back in the return line because the VP44 doesn't need anywhere near 70 GPH.

No. The VP won't take anywhere near 70 GPH. We were hoping it would so we wouldn't have to use a bypass, but such is NOT the case. You have to put a bypass in the fuel circuit because the Walbro pumps way, way more fuel than the VP will ever use. The Walbro is flooding the VP with fuel.

I get 70 GPH from the Walbro flow chart. At 25 PSI (15 PSI at the pump plus 10 PSI through the supply lines and filter) a Walbro pumps 70 GPH.

PS: I know some of you don't see 10 PSI of drop through your supply lines and filter. You also aren't pumping 70 GPH through them like the Walbro does. A VP takes less than 30 GPH at WOT.

 

I am not arguing that the walbrow is not a valid option, I just don't know enough about the flows to be willing to make the change. I will double check the flow ratings, but I think that Carter gave me that number for the flow. I will check and post the results in the morning.

 

Well, I know that there are several Walbros now installed on 24V engines and every one has similar pressures and ALL had to use a wide open bypass to get the pressure DOWN. The Walbro flows way, way more than the VP needs.

Riddle me this. What would the pressure at the VP be if you installed an open bypass with a Carter pump ? Ans: a few PSI at most. That tells you how much fuel the Walbro flows compared to the Carter. Hint: at idle, when the Carter makes 15 PSI, the VP is only taking a few GPH. At WOT it is only taking 30 GPH. 100% of the Carter's output goes to the VP because there is no bypass. The Carter is a very small pump compared to the Walbro.

Some people are talking about using a smaller Walbro.

 

You keep saying "Walbro" SD, but yet there are many different ones. Is everybody using the same part number that George 7941 mentioned? (392)

 

Yes, we are using the Walbro 392.

One person is using the Bosch from a Ford Superduty. I don't think he has it running as well as he would like. It pretty much requires a regulator because its flow is lower than the Walbro and thus the return line doesn't regulate it as well. It should still be a decent pump with a little fiddling.

 

According to Cummins, the stock pump is rated 90 gph and 18 psi max. When I called Carter, they claimed that the flow was proprietary. The cummins tech did not have a flow curve, so I do not know what pressure the 90 gph is at or the flow in the 15 psi range.

 

With all that extra fuel flowing back to the tank is that going to cause the fuel to foam ?And sence your flowing more does that also mean that you are going to have to chang your fuel filter more often ? Where are you checking preasure readings at ? how do you know exactly how much fuel is actually going through the ip.

 

There is now way the Carter pump is rated at 90 GPH, unless it falls off extremely fast. Look at it this way, at idle the VP takes about 5 GPH and most Carters make 10-15PSI at idle. So where is the other 85 GPH going ? There is no pressure relief or return flow line anywhere.

Does someone have a 2nd gen shop manual ? If so, what is the fuel pump flow test volume ? The 3rd gen fuel pump test for the in tank pump is for about 40 GPH and that pump is being used as a retrofit on 2nd gen trucks.

Foaming ? 70 GPH isn't that much fuel going into a 30ish gallon tank. It is only changing the volume of the tank 2+ times an hour. And if the Walbros 70 GPH is too much, what about people running 150 GPH pumps, where most (80%) of the pumps output circulates back to the fuel tank before it gets anywhere ?

Filter changing: how often you have to change filters has NOTHING to do with how fast you pump the fuel. When the tank is filled with fuel it has X amount of dirt in it and all that dirt gets caught in the filter regardless of pumping it fast or slow.

Pressures: I take mine at the filter lid, pre filter. Others take them at the injection pump.

I've never measured it and nor has anyone else that I know of. The theory is that if you supply the injection pump at a decent pressure its supply pump takes what it needs and that is how much it uses. The injection pumps will take what they need. There is no reason to measure it.

Whatever they don't take goes back to the tank via the bypass.

I think the fact the bypass is an open hose is confusing you. Just because it is open doesn't mean it doesn't have backpressure. In this case, with the Walbro pumping 70GPH, it is feeding BOTH the injection pump and the bypass line at 17-20 PSI at idle. When the injection pump takes more fuel, like at WOT, less fuel goes through the bypass and returns and then the pressure drops a bit. But only a few PSI.

To further clarify, with the Walbro we are pumping so much fuel through the system that the RETURN LINE has a bunch of backpressure. About 15 PSI to be exact. This is why the return line has to be improved if one wants to run a regulator.